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Biodiesel produciton from algae

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  1. A biodiesel production process catalyzed by the leaching of alkaline metal earths in methanol: from a model oil to microalgae lipids
    Abstract

    Veillette, M.; Giroir-Fendler, A.; Faucheux, N.; Heitz, M. 2017. A biodiesel production process catalyzed by the leaching of alkaline metal earths in methanol: from a model oil to microalgae lipids. Journal of Chemical Technology and Biotechnology. 92(5) 1094-1103

    BACKGROUND: A response surface methodology was used to study the reaction mechanism of strontium oxide (SrO) as a catalyst for a biodiesel production process using a model oil (composed of fatty acid methyl esters (FAME), free fatty acids (FFAs) and triglycerides). The influence of several factors (initial FAME content (0-30 wt%), initial FFAs content (oleic acid 0.20-2.7 wt%), temperature (40-60 degrees C), methanol to model oil ratio (11-43 wt%), catalyst to model oil ratio (0.5-2.5 wt%) and reaction time (5-30 min)) on the FAME yield, the FAME content, the pH of polar phase and the biodiesel alkalinity was studied.
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  2. A hybrid approach integrating arsenic detoxification with biodiesel production using oleaginous microalgae
    Abstract

    Arora, N.; Gulati, K.; Patel, A.; Pruthi, P. A.; Poluri, K. M.; Pruthi, V. 2017. A hybrid approach integrating arsenic detoxification with biodiesel production using oleaginous microalgae. Algal Research-Biomass Biofuels and Bioproducts. 2429-39

    A novel combinatorial approach integrating toxic and carcinogenic heavy metal arsenic (III, V) mitigation coupled to biodiesel production using oleaginous microalgae grown in synthetic soft water (SSW) was undertaken in this investigation. Among the four prospective microalgal species tested, Chorella minutissima and Scenedesmus sp. IITRIND2 were able to tolerate 500 mg L-1 of both the forms of As (III) and As (V) with a high metal bioconcentration factor (BCF) indicating that these strains can be categorized as hyper bioaccumulators of arsenic. These arsenic spiked microalgae showed a significant enhancement in the lipid production by accumulating large lipid droplets with minimal morphological changes. The biochemical composition analysis of these microalgal cells showed apparent decline in the protein, carbohydrate and photosynthetic pigments suggesting that the arsenic intake by the cells has remodeled its cellular composition in order to cope up with the heavy metal induced stress. The biodiesel derived from the microalgae was amenable and comparable to plant oil methyl esters with a high cetane number, oxidative stability and low cold flow plugging properties. This salient approach exhibits two fold advantages, which include safe removal of carcinogenic metal arsenic from potable water sources as well as high yield of lipid production. This novel integrative innovative technology has a strong prospective path for verdurous environment and renewable fuels resulting in socioeconomic welfare. (C) 2017 Elsevier B.V. All rights reserved.
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  3. A novel microalgal lipid extraction method using biodiesel (fatty acid methyl esters) as an extractant
    Abstract

    Huang, W. C.; Park, C. W.; Kim, J. D. 2017. A novel microalgal lipid extraction method using biodiesel (fatty acid methyl esters) as an extractant. Bioresource Technology. 22694-98

    Although microalgae are considered promising renewable sources of biodiesel, the high cost of the downstream process is a significant obstacle in large-scale biodiesel production. In this study, a novel approach for microalgal biodiesel production was developed by using the biodiesel as an extractant. First, wet microalgae with 70% water content were incubated with a mixture of biodiesel/methanol and penetration of the mixture through the cell membrane and swelling of the lipids contained in microalgae was confirmed. Significant increases of lipid droplets were observed by confocal microscopy. Second, the swelled lipid droplets in microalgae were squeezed out using mechanical stress across the cell membrane and washed with methanol. The lipid extraction efficiency reached 68%. This process does not require drying of microalgae or solvent recovery, which the most energy-intensive step in solvent-based biodiesel production. (C) 2016 Elsevier Ltd. All rights reserved.
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  4. A review of biodiesel production from microalgae
    Abstract

    Dickinson, S.; Mientus, M.; Frey, D.; Amini-Hajibashi, A.; Ozturk, S.; Shaikh, F.; Sengupta, D.; El-Halwagi, M. M. 2017. A review of biodiesel production from microalgae. Clean Technologies and Environmental Policy. 19(3) 637-668

    As the search for alternatives to fossil fuels continues, microalgae have emerged as a promising renewable feedstock for biodiesel. Many species contain high lipid concentrations and require simple cultivation-including reduced freshwater and land area needs-compared to traditional crops used for biofuels. Recently, technological advancements have brought microalgae biodiesel closer to becoming economically feasible through increased efficiency of the cultivation, harvesting, pretreatment, lipid extraction, and transesterification subsystems. The metabolism of microalgae can be favorably manipulated to increase lipid productivity through environmental stressors, and "green" techniques such as using flue gas as a carbon source and wastewater as a media replacement can lower the environmental impact of biodiesel production. Through life cycle assessment and the creation of process models, valuable insights have been made into the energy and material sinks of the manufacturing process, helping to identify methods to successfully scale up microalgae biodiesel production. Several companies are already exploring the microalgae industry, offsetting operating costs through isolation of co-products and careful unit operation selection. With numerous examples drawn from industry and the literature, this review provides a practical approach for creating a microalgae biodiesel facility.
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  5. An in vitro study on enzymatic transesterification of microalgal oil from chlorella vulgaris for biodiesel synthesis using immobilized steptomyces sp. Lipase
    Abstract

    Xavier, I. J.; Sridhar, S. 2017. An in vitro study on enzymatic transesterification of microalgal oil from chlorella vulgaris for biodiesel synthesis using immobilized steptomyces sp. Lipase. Indo American Journal of Pharmaceutical Sciences. 4(3) 538-549

    Biodiesel is advised for use as an alternative fuel for conventional petroleum-based diesel because it is a renewable, with an environmentally friendly emission profile and is readily biodegradable. The effect of various growing conditions on biodiesel properties produced from Chlorella vulgaris has been investigated. The Chlorella vulgaris grown at different initial pH (4.0, 5.0, 6.0, 7.0 and 8.0) and Ammonia sources namely ammonium nitrate, ammonium sulphate, ammonium chlorite, ammonium tartrate and urea in laboratory condition. Chlorella vulgaris showed a gradual increase in cell number from pH 5.0 to 7.0. Maximum growth biomass of 6.6 mg/mL and Protein content 68.51 mg/mL was recorded at pH 7.0 on 7th day. Among the ammonia sources the maximum growth biomass of 7.8 mg/mL and maximum total protein content of 70 mg/mL was recorded in the presence of urea on 7th day. For lipase production, Streptomyces was inoculated in to the modified large production medium at different pH (3.0, 4.0, 5.0, 6.0, 7.0 and 8.0), carbon source (glucose, sucrose, lactose and maltose) and nitrogen sources (ammonium sulphate, ammonium nitrate yeast extract and peptone). The Streptomyces Sp. was able to release a maximum protein content of 67mg/ml at pH 8.0 after 66 h and lipase of 77 U/ml at pH 8.0 after 36 h. The maximum extra cellular protein content of 71 mg/ml in the existence of Sucrose at 36 h and maximum enzyme activity of 91 U/ml at 96 h compared to the rest of sugars. Whereas, the occurrence of nitrogen sources the yeast extract supported a maximum extracellular protein content of 74 mg/ml at 36 h and lipase production of 94U/ml at 36 h.
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  6. Biodiesel fuel production by enzymatic microalgae oil transesterification with ethanol
    Abstract

    Makareviciene, V.; Gumbyte, M.; Skorupskaite, V.; Sendzikiene, E. 2017. Biodiesel fuel production by enzymatic microalgae oil transesterification with ethanol. Journal of Renewable and Sustainable Energy. 9(2)

    This paper discusses the application of the enzymatic transesterification of algae oil with ethanol for the production of biodiesel fuel. Seven commercial lipases were tested, and the most effective lipase preparation-Lipolase 100L-was selected. The transesterification process was optimised by applying response surface methodology. The interaction of the molar ratio of ethanol to oil, the process duration, the lipase concentration, and the temperature was evaluated. Transesterification experiments were performed under different conditions, and the transesterification yield was measured. On the basis of the transesterification yield, a quadratic model was built, and the optimal conditions were determined: a temperature of 30 degrees C, a lipase amount of 10%, and an ethanol to oil molar ratio of 3:1. After 26 h, the transesterification yield was increased to 96.9%, and the requirements of the European standard for biodiesel fuel (EN 14214) were met. Published by AIP Publishing.
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  7. Biodiesel fuel production from algal lipids using supercritical methyl acetate (glycerin-free) technology
    Abstract

    Patil, P. D.; Reddy, H.; Muppaneni, T.; Deng, S. G. 2017. Biodiesel fuel production from algal lipids using supercritical methyl acetate (glycerin-free) technology. Fuel. 195201-207

    Supercritical methyl acetate (SCMA) technology was demonstrated for converting total lipids from Nannochloropsis salina into fatty acid methyl esters (FAMEs) and triacetin (TA). In this non-catalytic process, triacetin is produced instead of glycerin as a side-product during transesterification which is miscible with FAME and can be readily used as biodiesel fuel (BDF). Supercritical carbon-dioxide (SC-CO2), clean and green technology was employed to extract total lipids from algal biomass. The process parameters such as lipid to methyl acetate molar ratio, reaction temperature and reaction time were studied to evaluate their effects on the FAME yield and algal biodiesel fuel yield. Algal lipid characterization and algal biodiesel fuel analysis were carried out using analytical instruments such as FTIR and GC-MS. Thermogravimetric analysis under nitrogen and oxygen environments was performed to examine the thermal and oxidative stability of the algal biodiesel fuel. A micro-elemental analysis (CHNOS) of total algal lipid and biodiesel fuel was performed according to ASTM methods. The fuel properties of algal biodiesel fuel produced were compared with those of the regular diesel and biodiesel American Society for Testing and Materials (ASTM) standards. (C) 2017 Elsevier Ltd. All rights reserved.
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  8. Biodiesel production from microalgae oil through conventional and ultrasonic methods
    Abstract

    Singh, A.; Pal, A.; Maji, S. 2017. Biodiesel production from microalgae oil through conventional and ultrasonic methods. Energy Sources Part a-Recovery Utilization and Environmental Effects. 39(8) 806-810

    In the present study, the oil extracted from the microalga Neochloris oleoabundans was used for producing biodiesel. The viscosity of microalgal oil was very high so transesterification was done by an ultrasonic method and a simple basic method. Free fatty acid content in oil was found high so a two-step transesterification reaction was used. Maximum yield of algal oil methyl ester was acquired by the ultrasonic method (98%) with improved physicochemical characteristics, whereas the biodiesel yield obtained by simple transesterification process was low (91%). The maximum oil content in N. oleoabundans was found to be 42% and major fatty acids include palmitic acid, oleic acid, and linoleic acid. Finally, it was conferred that the ultrasonic-assisted transesterification method is the best technique for biodiesel production from microalgal oil.
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  9. Biodiesel production from microalgae Spirulina maxima by two step process: Optimization of process variable
    Abstract

    Rahman, M. A.; Aziz, M. A.; Al-khulaidi, R. A.; Sakib, N.; Islam, M. 2017. Biodiesel production from microalgae Spirulina maxima by two step process: Optimization of process variable. Journal of Radiation Research and Applied Sciences. 10(2) 140-147

    Biodiesel from green energy source is gaining tremendous attention for ecofriendly and economically aspect. In this investigation, a two-step process was developed for the production of biodiesel from microalgae Spirulina maxima and determined best operating conditions for the steps. In the first stage, acid esterification was conducted to lessen acid value (AV) from 10.66 to 0.51 mgKOH/g of the feedstock and optimal conditions for maximum esterified oil yielding were found at molar ratio 12: 1, temperature 60 degrees C, 1% (wt%) H2SO4, and mixing intensity 400 rpm for a reaction time of 90 min. The second stage alkali transesterification was carried out for maximum biodiesel yielding (86.1%) and optimal conditions were found at molar ratio 9: 1, temperature 65 degrees C, mixing intensity 600 rpm, catalyst concentration 0.75% (wt%) KOH for a reaction time of 20 min. Biodiesel were analyzed according to ASTM standards and results were within standards limit. Results will helpful to produce third generation algal biodiesel from microalgae Spirulina maxima in an efficient manner. (C) 2017 The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.
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  10. Biodiesel production from Spirulina microalgae feedstock using direct transesterification near supercritical methanol condition
    Abstract

    Shirazi, H. M.; Karimi-Sabet, J.; Ghotbi, C. 2017. Biodiesel production from Spirulina microalgae feedstock using direct transesterification near supercritical methanol condition. Bioresource Technology. 239378-386

    Microalgae as a candidate for production of biodiesel, possesses a hard cell wall that prevents intracellular lipids leaving out from the cells. Direct or in situ supercritical transesterification has the potential for destruction of microalgae hard cell wall and conversion of extracted lipids to biodiesel that consequently reduces the total energy consumption. Response surface methodology combined with central composite design was applied to investigate process parameters including: Temperature, Time, Methanol-to-dry algae, Hexane-to-dry algae, and Moisture content. Thirty-two experiments were designed and performed in a batch reactor, and biodiesel efficiency between 0.44% and 99.32% was obtained. According to fatty acid methyl ester yields, a quadratic experimental model was adjusted and the significance of parameters was evaluated using analysis of variance (ANOVA). Effects of single and interaction parameters were also interpreted. In addition, the effect of supercritical process on the ultrastructure of microalgae cell wall using scanning electron spectrometry (SEM) was surveyed. (C) 2017 Elsevier Ltd. All rights reserved.
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  11. Biodiesel synthesis from microalgal lipids using tungstated zirconia as a heterogeneous acid catalyst and its comparison with homogeneous acid and enzyme catalysts
    Abstract

    Guldhe, A.; Singh, P.; Ansari, F. A.; Singh, B.; Bux, F. 2017. Biodiesel synthesis from microalgal lipids using tungstated zirconia as a heterogeneous acid catalyst and its comparison with homogeneous acid and enzyme catalysts. Fuel. 187180-188

    Downstream step of catalytic conversion is scarcely investigated area in microalgal biodiesel production process. In this study a heterogeneous acid catalyst, tungstated zirconia (WO3/ZrO2) is evaluated for conversion of S. obliquus lipids. Catalytic efficiency of tungstated zirconia catalyst was compared to the homogeneous acid catalyst and enzyme catalyst in terms of conversion efficiency, reaction parameters, energy consumption and reusability. Tungstated zirconia catalyst showed maximum biodiesel conversion of 94.58% at 100 degrees C temperature, 12:1 methanol to oil molar ratio and 15% of catalyst amount based on oil weight in 3, h. Tungstated zirconia showed comparable biodiesel conversion to homogeneous catalyst and higher conversion than the enzyme catalyst. The time requirement for heterogeneous catalyst was lowest, while, the energy consumption was highest among the selected catalysts. Most of the fuel properties of biodiesel synthesized by tungstated zirconia catalyzed conversion of S. obliquus lipids comply with the specifications set by ASTM and EN standards. (C) 2016 Elsevier Ltd. All rights reserved.
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  12. Continuous production of biodiesel from microalgae by extraction coupling with transesterification under supercritical conditions
    Abstract

    Zhou, D.; Qiao, B. Q.; Li, G.; Xue, S.; Yin, J. Z. 2017. Continuous production of biodiesel from microalgae by extraction coupling with transesterification under supercritical conditions. Bioresource Technology. 238609-615

    Raw material for biodiesel has been expanded from edible oil to non-edible oil. In this study, biodiesel continuous production for two kinds of microalgae Chrysophyta and Chlorella sp. was conducted. Coupling with the supercritical carbon dioxide extraction, the oil of microalgae was extracted firstly, and then sent to the downstream production of biodiesel. The residue after decompression can be reused as the material for pharmaceuticals and nutraceuticals. Results showed that the particle size of microalgae, temperature, pressure, molar ration of methanol to oil, flow of CO2 and n-hexane all have effects on the yield of biodiesel. With the optimal operation conditions: 40 mesh algae, extraction temperature 60 degrees C, flow of n-hexane 0.4 ml/min, reaction temperature: 340 degrees C, pressure: 18-20 MPa, CO2 flow of 0.5 L/min, molar ration of methanol to oil 84: 1, a yield of 56.31% was obtained for Chrysophyta, and 63.78% for Chlorella sp. due to the higher lipid content. (C) 2017 Published by Elsevier Ltd.
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  13. Conversion of microalgal lipids to biodiesel using chromium-aluminum mixed oxide as a heterogeneous solid acid catalyst
    Abstract

    Guldhe, A.; Moura, C. V. R.; Singh, P.; Rawat, I.; Moura, E. M.; Sharma, Y.; Bux, F. 2017. Conversion of microalgal lipids to biodiesel using chromium-aluminum mixed oxide as a heterogeneous solid acid catalyst. Renewable Energy. 105175-182

    Heterogeneous solid acid catalyzed conversion of microalgal lipids to biodiesel is a scarcely studied area. In this study chromium-aluminum mixed oxide catalyst was investigated for catalytic conversion of microalgal lipids to biodiesel. Lipids from Scenedesmus obliquus grown in an open raceway pond (3000L) was used as feedstock. Reaction variables such as temperature, methanol to oil molar ratio and catalyst amount were optimized using response surface methodology. FAME conversion of 98.28% was achieved using chromium-aluminum catalyst at 80 degrees C, with methanol to oil molar ratio of 20:1 and catalyst amount of 15%. Catalytic efficiency of this heterogeneous solid acid catalyst was compared to a homogeneous acid catalyst (sulfuric acid). Chromium-aluminum mixed oxide catalyst can be effectively used for 4 batches of conversion reactions without significant loss in its activity. (C) 2016 Elsevier Ltd. All rights reserved.
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  14. Cultivation of Chlorella vulgaris with swine wastewater and potential for algal biodiesel production
    Abstract

    Nam, K.; Lee, H.; Heo, S. W.; Chang, Y. K.; Han, J. I. 2017. Cultivation of Chlorella vulgaris with swine wastewater and potential for algal biodiesel production. Journal of Applied Phycology. 29(3) 1171-1178

    In this study, an alga-based simultaneous process of treating swine wastewater (SWW) and producing biodiesel was explored. Chlorella vulgaris (UTEX-265) was employed as a model species, and a SWW-based medium was prepared by dilution with tap water. Chlorella vulgaris grew well in the SWW-based medium, and at optimum dilution ratios, it exceeded the conventional culture medium in terms of biomass concentration and productivity. In eightfold diluted SWW, which supported the maximum growth, biomass productivity was 0.247 g L-1 day(-1), while the productivity was merely 0.165 g L-1 day(-1) in standard tris-acetate-phosphorous (TAP) algal medium. In addition, fatty acid methyl ester (FAME) productivity was greater in the SWW-based medium (0.067 versus 0.058 g L-1 day(-1)). This enhanced productivity resulted in more than 95 % removal of both nitrogen and phosphorous. All these show that C. vulgaris cultivation is indeed possible in a nutrient-rich wastewater with appropriate dilution, and in so doing, the wastewater can effectively be treated.
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  15. Cultivation of four microalgae species in the effluent of anaerobic digester for biodiesel production
    Abstract

    Kim, G. Y.; Yun, Y. M.; Shin, H. S.; Han, J. I. 2017. Cultivation of four microalgae species in the effluent of anaerobic digester for biodiesel production. Bioresource Technology. 224738-742

    This study investigated if an effluent from anaerobic digestion (AD) system can be used as a nutrients source for the microalgae cultivation, and in so doing, if the effluent can be properly treated. Nitrogen and phosphorus in the AD effluent well supported microalgal growth, and their removal efficiency reached > 97.9% and 99.2%, respectively. Among four different algal species tested, Micractinium inermum particularly stood out, showing the highest biomass and FAME productivity: 0.16 g (1) d(1) with 3.23 g L-1 of dry cell weight, and 0.04 g L-1 d(1) with 27.54% (w/w) of FAME contents, respectively. As the concentrations of the nutrients decreased over time, the FAME contents were increased and its quality as well, satisfying several biodiesel quality standards. This study supports that the AD effluent can indeed serve as a cheap and nutrient-rich medium for microalgae cultivation, and equally importantly, microalgae can be a workable treatment option for it. (C) 2016 Elsevier Ltd. All rights reserved.
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  16. Cultivation, extraction and optimization of biodiesel production from potential microalgae Euglena sanguinea using eco-friendly natural catalyst
    Abstract

    Kings, A. J.; Raj, R. E.; Miriam, L. R. M.; Visvanathan, M. A. 2017. Cultivation, extraction and optimization of biodiesel production from potential microalgae Euglena sanguinea using eco-friendly natural catalyst. Energy Conversion and Management. 141224-235

    Algal biofuels have caught worldwide attention, due to the success of first and second generation biofuels on combing environmental concerns in spite of many challenges. Microalgae are the potential and sustainable fuel source with carbon neutrality, where selection of promising strain is crucial for effective biofuel generation. Euglena sanguinea one such robust freshwater species with high lipid productivity was explored on laboratory scale as well as in mass scale in raceway pond. The extracted oil's fatty acid value was only 3.8 mg KOH g(-1) and had 93% triglycerides. Acid value was reduced to similar to 0.3 mg KOH g(-1) by esterification and the optimized parameters obtained were: methanol/oil ratio: 036, H2SO4: 10 vol.%, time: 42 min. In the subsequent transesterification process natural, recoverable and eco-friendly white mussel shell was used. Maximum yield of similar to 98% was obtained at 6 wt.% of calcinated CaO for the reaction time of 80 min at 0.35 methanol/oil ratio. The GC-MS analysis of the algal biodiesel showed the presence of saturated fatty acids: C16:0, C18:0, C22:0, C24:0 and monounsaturated fatty acids C18:1 at appropriate level to provide better oxidation stability and combustion properties to use it for automotive application without any major engine modifications.(C) 2016 Elsevier Ltd. All rights reserved.
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  17. Development of a harvesting technique for large-scale microalgal harvesting for biodiesel production
    Abstract

    Koley, S.; Prasad, S.; Bagchi, S. K.; Mallick, N. 2017. Development of a harvesting technique for large-scale microalgal harvesting for biodiesel production. Rsc Advances. 7(12) 7227-7237

    Harvesting imposes a major constraint in microalgal downstream processes and cost-effective production of various high value products. In this study, different harvesting techniques were assessed under a single domain to identify the most suitable one for large-scale harvesting of green microalgae for biodiesel purpose. In the laboratory, Scenedesmus obliquus showed a flocculation efficiency of 83.2% at pH 12 after 1 h. Maximum flocculation efficiencies of 80.2, 95 and 91%, respectively were observed for FeCl3 at 200 mg L-1, alum at 250 mg L-1 and chitosan at 20 mg L-1 after 1 h. Electro-flotation at 24 V and dissolved air flotation with 1 mg L-1 of alum also revealed flocculation efficiencies of 99 and 91% respectively, after 1 h. For Chlorella vulgaris, similar trends were also observed. Under field trials with 1000 L algal suspension, electro-flotation required a voltage of 60 V to achieve a flocculation efficiency of similar to 90% after 24 h. Dissolved air flotation also showed a flocculation efficiency of same magnitude after 7 h, but with 10 mg L-1 of alum. Thus electro-flotation required a profoundly higher voltage with increasing culture volume, whereas for dissolved air flotation a much higher concentration of alum was entailed. Both the processes also depicted a significantly longer time period to achieve the required flocculation efficiency. On the other hand, pH-induced flocculation was found to be the most pertinent one for large-scale set-ups, and emerged to be efficient, cost-effective and eco-friendly as the supernatant can be reused as growth medium by re-supplementing the nutrients and adjusting the pH.
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  18. Development of a single phase nitrate feeding strategy for enhanced lipid productivity from green microalgae for biodiesel production
    Abstract

    Sonkar, S.; Mallick, N. 2017. Development of a single phase nitrate feeding strategy for enhanced lipid productivity from green microalgae for biodiesel production. Environmental Progress & Sustainable Energy. 36(1) 222-231

    Biomass productivity and cellular lipid content are two major components that influence the ultimate lipid productivity from algal biomass. In this report, a nitrate feeding strategy was developed taking three green microalgae, Scenedesmus obliquus, Chlorella vulgaris, and C. minutissima, to achieve higher lipid productivity under single phase cultivation. Four different strategies, i.e. nitrate-sufficient, nitrate-deficient, biphasic nitrate-deficient and low-dose sequential nitrate feeding, were examined. The biphasic nitrate-deficient approach depicted the maximum lipid productivity. To bring this biphasic approach to a single phase, sequential limited nitrate feeding strategy was examined. This showed nitrate supplementation with a 1/100th dose of standard N 11 medium at an interval of 3 days resulted in a significant rise in lipid productivity. The biodiesel samples also demonstrated the predominance of saturated and monounsaturated fatty acid methyl esters. This study, therefore, suggests that with appropriate standardization, the usual biphasic approach can be brought down to a single phase, thereby reducing the overall cost of microalgal biomass production for biodiesel purpose. Moreover, this strategy is user-friendly, and would reduce the nitrate requirements for large-scale cultivation, thus, would result in cost-effective and eco-friendly biodiesel production from microalgae. (c) 2016 American Institute of Chemical Engineers Environ Prog, 36: 222-231, 2017
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  19. Development of an X-Shape airlift photobioreactor for increasing algal biomass and biodiesel production
    Abstract

    Pham, H. M.; Kwak, H. S.; Hong, M. E.; Lee, J.; Chang, W. S.; Sim, S. J. 2017. Development of an X-Shape airlift photobioreactor for increasing algal biomass and biodiesel production. Bioresource Technology. 239211-218

    The aim of this work was to develop a high efficient photobioreactor for increasing biomass and lipid production in microalgae by assessment of the hydrodynamic properties and k(L)a which are important parameters for improving the algal cultivation efficiency. We designed three different photobioreactors (H-Shape, X-Shape and serial-column). Among them, X-Shape showed the highest hydrodynamic properties and kLa for algal cultivation. Thus, we evaluated the biomass and the lipid production in a 20 L scale-up X-Shape photobioreactor. The biomass and lipid production from X-Shape photobioreactor are 1.359 +/- 0.007 g L-1 and 117.624 +/- 3.522 mg L-1, respectively; which are 30.05% and 23.49% higher than those from the control photobioreactor. Finally, we observed the lipid from X-Shape had high MUFAs, CN and low IV, which is suitable for high quality of biodiesel, suggesting that it can be practicably utilized for mass production of algal biofuel. (C) 2017 Elsevier Ltd. All rights reserved.
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  20. Effect of the storage condition of microalgae on hydrochar lipids and direct esterification-transesterification of hydrochar lipids for biodiesel production
    Abstract

    Phuoc, V. T.; Yoshikawa, K. 2017. Effect of the storage condition of microalgae on hydrochar lipids and direct esterification-transesterification of hydrochar lipids for biodiesel production. Aims Energy. 5(1) 39-53

    The hydrochar product from the hydrothermal carbonization (HTC) of microalgae contains most of fatty acids (FAs) in the original microalgae. In the hydrochar, FAs exist in both types of bound fatty acids (BFAs) and free fatty acids (FFAs). Besides, when the microalgae paste is stored at the room temperature (25 degrees C) for one day, there is an increase of total fatty acids (TFAs) and free fatty acids (FFAs) in microalgae. The hydrochar from this microalgae paste was proved to have a higher amount of TFAs and a higher percentage of FFAs/TFAs compared to the ordinary hydrochar (without the additional storage step) in this research. Both of these factors favor for the subsequent acid catalyzed esterification-transesterification reaction of hydrochar lipids. In summary, a process based on a combination of the storage of fresh microalgae, the HTC of microalgae paste, and the direct esterification-transesterification of the hydrochar has been developed for biodiesel production. With the additional storage step of fresh microalgae, the total biodiesel yield has been improved of 19.3% in the optimum condition.
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  21. Efficiency of lipid accumulating Actinomycetes isolated from soil for biodiesel production: Comparative study with microalgae
    Abstract

    El-Sheekh, M. M.; Allam, N. G.; Shabana, S. A.; Azab, M. M. 2017. Efficiency of lipid accumulating Actinomycetes isolated from soil for biodiesel production: Comparative study with microalgae. Energy Sources Part a-Recovery Utilization and Environmental Effects. 39(9) 883-892

    Due to the global warming and the increase of toxic gases emitted from the fossil fuels and the increase of energy demand, it is necessary to look for alternative sources for biodiesel. In this work, fifty bacterial species were isolated from soil samples and the isolated bacteria were tested for their ability of lipid production. The most potent lipid producer was identified as Streptomyces coelicolor A3-NC:003888.3 using the 16S rDNA partial sequencing technique. The lipid production process was performed in a bench scale for pure S. coelicolor, Chlorella vulgaris (as a standard biodiesel producer) and mixed algal bacterial culture as a comparative study. The results indicated that 93% wt of fatty acids of Streptomyces was converted to the corresponding fatty acid methyl esters (biodiesel). After transesterification of the produced lipids, the obtained oil was characterized according to American Society for Testing and Materials (ASTM) standards. The density of bacterial biodiesel was 0.866 and that of algal biodiesel was 0.797; also the specific gravity was 0.866 and 0.784 for bacterial and algal biodiesel, respectively, giving more lubricant characters for bacterial biodiesel. The gross heating value of bacterial biodiesel (43426 Kj/Kg) was higher than that of algal biodiesel (41896 Kj/Kg), dependently, the cetane number of bacterial biodiesel (38) was little lower than that of algal biodiesel (43).
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  22. Enhanced extraction of lipids from microalgae with eco-friendly mixture of methanol and ethyl acetate for biodiesel production
    Abstract

    Wu, J. C.; Alam, M. A.; Pan, Y.; Huang, D. L.; Wang, Z. M.; Wang, T. J. 2017. Enhanced extraction of lipids from microalgae with eco-friendly mixture of methanol and ethyl acetate for biodiesel production. Journal of the Taiwan Institute of Chemical Engineers. 71323-329

    Developing technologies for the production of biofuel from renewable resources is a field of interest for many researchers. Lipid extraction could be an important step in the microalgae biodiesel production process. Factors affecting intracellular lipid extraction from Chlorella sp. cultivated in outdoor raceway ponds were investigated; an optimized procedure for extraction of total and non-polar lipids using ecofriendly solvent combination of ethyl acetate and methanol was proposed. The effects of solvent, and extraction variables (temperature, time, ratio of solvent and biomass, ratio of ethyl acetate and methanol) on total lipid content, and lipid class were examined via single-factor experiments coupled with response surface methodology (RSM) using Box Behnlcen design (BBD). The results revealed that the maximum lipid extraction yield was 18.1% obtained after extraction 120 min, extraction temperature 60 degrees C and M/EA ratio was 2:1. Fatty acid profiles of lipid were determined; palmitic acid (C16:0), palmitoleic (C16:1) oleic acid (C18:1), linoleic acid (08:2) and linolenic acid (C18:3) are the most abundant fatty acids, indicating the great capacity of lipid extraction from microalgae for biodiesel production. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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  23. Enhanced lipid extraction from microalgae in biodiesel production
    Abstract

    Kim, M. G.; Hwang, H. W.; Nzioka, A. M.; Kim, Y. J. 2017. Enhanced lipid extraction from microalgae in biodiesel production. Hemijska Industrija. 71(2) 167-174

    In order to secure more effective lipid extraction method, this research investigated new lipid extraction method using laser with absorbent and sought its optimum operation control. In addition, this study compared lipid extraction efficiency and FAME conversion rate between laser extraction method at optimum condition and existing extraction method. Results from experiments for optimizing lipid extraction method using laser showed that the maximum extraction efficiency (81.8%) was attained when using laser with an output capacity of 75Wh/L. Extraction efficiency increased up to 90.8% when microwave treatment as pretreatment process was conducted. Addition of absorbents during lipid extraction process with laser showed higher extraction efficiency than laser and chemical method. It was also found that laser extraction method with absorbent had higher total fatty acid content (853.7 mg/g oil) in extracted lipid than chemical extraction method (825.4 mg/g oil). Furthermore, it had the highest FAME conversion rate (94.2%).
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  24. Enzymatic biodiesel production from microalgae biomass using propane as pressurized fluid
    Abstract

    Marcon, N. S.; Colet, R.; Balen, D. S.; de Pereira, C. M. P.; Bibilio, D.; Priamo, W.; Bender, J. P.; Steffens, C.; Dalla Rosa, C. 2017. Enzymatic biodiesel production from microalgae biomass using propane as pressurized fluid. Canadian Journal of Chemical Engineering. 95(7) 1340-1344

    The search for renewable and sustainable fuels is becoming increasingly more important. As a result, the use of biomass as an energy source is one of the most promising methods in the reduction of energy dependence on non-renewable fossil fuels. In order to reduce the amount of solvent used during direct transesterification, this study has aimed at producing biodiesel from microalgae (Chlorella vulgaris) biomass using enzymatic catalysis (Novozym 435) and pressurized fluid (propane). The effects of pressure (3000 to 8000 kPa), temperature (323.15 to 353.15K), and exposure time (1 to 8h) have been studied through the experimental design for esters conversion. The newly investigated system showed consistency through the experimental design technique, evaluating the effect of significant variables such as time, temperature, and pressure in the process. The good conversions yielded have been achieved using mild temperature and higher pressure conditions, demonstrating that this process has great potential for obtaining biodiesel from microalgae biomass.
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  25. Evaluation of effective nutritional parameters for Scenedesmus sp microalgae culturing in a photobioreactor for biodiesel production
    Abstract

    Samkhaniyani, F.; Najafpour, G. D.; Ardestani, F. 2017. Evaluation of effective nutritional parameters for Scenedesmus sp microalgae culturing in a photobioreactor for biodiesel production. International Journal of Environmental Science and Technology. 14(5) 1037-1046

    Recently, microalgae are considered as lipid sources for biodiesel production. A photobioreactor was designed and fabricated for Scenedesmus sp. microalgae cultivation. The effect of several nitrogen sources, light intensity, iron ions, silicon, magnesium sulfate and ethanol concentrations on Scenedesmus sp. microalgae growth were investigated. For incubation period of 8 days, sodium nitrate and ammonium carbonate were the best nitrogen sources with biomass concentrations of 2.373 and 2.254 g L-1, respectively. Microalgae growth was reduced using nitrogen concentrations above 0.7 g L-1. In the first 10 days of incubation, maximum cell dry weight (0.7 g L-1) was obtained with light intensity of 10,000 lx, whiles after that, the results were desired (1 g L-1) using interior lighting at 7500 lx. Magnesium sulfate had a positive effect on cell growth. The biomass concentration of 1.65 g L-1 was obtained using 0.06 g L-1 magnesium sulfate. Maximum obtained biomass with silicon (0.7 Mm), ethanol (1.8 mL L-1) and ferric ammonium citrate (0.02 g L-1) was 1.7 and 1.3 and 2.16 g L-1, respectively. Logistic model was found to be a suitable model for cell growth forecast. Fatty acid analysis showed that composition of the most dominant synthesized fatty acids, palmitic and oleic acids, was 21.16 and 33.58%, respectively. Oil produced by Scenedesmus sp. microalgae composed of 49.08% saturated and 43.53% unsaturated fatty acids has a suitable composition for a desired biodiesel.
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  26. Isolation and Characterization of Native Microalgae from the Peruvian Amazon with Potential for Biodiesel Production
    Abstract

    Cobos, M.; Paredes, J. D.; Maddox, J. D.; Vargas-Arana, G.; Flores, L.; Aguilar, C. P.; Marapara, J. L.; Castro, J. C. 2017. Isolation and Characterization of Native Microalgae from the Peruvian Amazon with Potential for Biodiesel Production. Energies. 10(2)

    Biodiesel production from microalgae triacylglycerols is growing, because this feedstock is a more sustainable and advantageous alternative. In this study, we isolated and identified fourteen strains of native microalgae from the Peruvian Amazon. These strains showed great heterogeneity in biomass productivity, lipid productivity and lipid content, and thus, three of them (Acutodesmus obliquus, Ankistrodesmus sp. and Chlorella lewinii) were selected for further evaluation under culture of nitrogen-sufficient (+N) and nitrogen-deficient (-N) Chu medium No. 10. These microalgae species showed modifications in biomolecule content (protein, lipid and carbohydrate) with a pronounced increase of lipids and carbohydrate and a decrease of protein content under stress culture. Furthermore, the fatty acid profile was peculiar for each species, and these patterns showed evident changes, particularly in the proportion of saturated and monounsaturated fatty acids. The results of this research suggest that the isolated native microalgae, from the Peruvian Amazon, could be suitable candidates for biodiesel production.
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  27. Life cycle assessment of microalgae based biodiesel production to evaluate the impact of biomass productivity and energy source
    Abstract

    Togarcheti, S. C.; Mediboyina, M. K.; Chauhan, V. S.; Mukherji, S.; Ravi, S.; Mudliar, S. N. 2017. Life cycle assessment of microalgae based biodiesel production to evaluate the impact of biomass productivity and energy source. Resources Conservation and Recycling. 122286-294

    In the present study the life cycle assessment (LCA) of three scenarios for biodiesel production from Scenedesmus dimorphus, a freshwater microalgae, cultivated in open raceway ponds using primary and secondary data was investigated. The main differences in the scenarios were related to biomass productivity, mode of culture mixing and type of energy source. The process steps included algal cultivation in open raceway ponds, harvesting by chemical flocculation, dewatering by mechanical drying option (MDO)/Spray Drying (SD) followed by extraction, reaction, and purification. Supplementation of the cultivation process with electricity derived from defatted algal biomass waste was also analyzed. The scenarios were evaluated for energy demand and environmental impacts amongst the boundary conditions based on a "cradle-to-gate" inventory. The results revealed that among all the scenarios, cultivation in raceway pond was ascertained to be the most energy intensive process with the mode of culture mixing and biomass productivity being the principal determinants. The impacts were found to be directly linked to energy demand and had an inverse relationship with biomass productivity. The geographic location of the energy sources affected the environmental implications of a given process. The integration of defatted algal biomass waste derived electricity with the cultivation system showed a minor reduction in the overall energy demand. (C) 2017 Elsevier B.V. All rights reserved.
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  28. Microalgae as a potential source for biodiesel production: techniques, methods, and other challenges
    Abstract

    Arenas, E. G.; Palacio, M. C. R.; Juantorena, A. U.; Fernando, S. E. L.; Sebastian, P. J. 2017. Microalgae as a potential source for biodiesel production: techniques, methods, and other challenges. International Journal of Energy Research. 41(6) 761-789

    This paper reviews some of the most important aspects of microalgae as a potential source for biodiesel production. Microalgae are photosynthetic microorganisms that can grow rapidly in a variety of environments because of their unicellular or multicellular structure depending on the species. They have the advantage of self-reproduction using solar energy and converting it into chemical energy via photosynthesis. This process concludes a full cycle in a few days, obtaining higher lipid yields than terrestrial crops. This review shows several techniques and some methodologies used in the biodiesel production process from microalgae as well as the challenges that must be overcome for large-scale process and in bio-refineries. Copyright (C) 2016 John Wiley & Sons, Ltd.
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  29. Microalgae biofuels: Induction of lipid synthesis for biodiesel production and biomass residues into hydrogen conversion
    Abstract

    Chernova, N. I.; Kiseleua, S. V. 2017. Microalgae biofuels: Induction of lipid synthesis for biodiesel production and biomass residues into hydrogen conversion. International Journal of Hydrogen Energy. 42(5) 2861-2867

    The paper is dedicated to new unconventional sources of non-food renewable feedstock for third generation biofuel - microalgae biomass. Methods of lipid induction in microalgae have been considered. It represents the results of advanced microalgae strains state-ofthe-art investigations lipid producers. The paper discusses selection of stressors at two-stage culturing, where 1st stage includes culturing under most optimal conditions to produce maximum amount of biomass, and at 2nd stage biosynthesis and accumulation of lipids in biomass occurs. Types of stressors used for lipid induction have been briefly reviewed on the basis of foreign studies. Proper experimental results on isolation of new candidate microalgae strains from natural sources, as well as on selection of stressors for lipid induction have been shown and discussed. Nitrogen and phosphoric starvation, high and low illuminance, along with temperature conditions have been studied as stressors. Effectiveness of lipid-containing microalgae screening technique by fluorescent dye Nile red staining has been determined. Processible fast-growing Arhtrospira platensis microalgae/cyanobacteria use perspectiveness as a model for selection of stressors and overall lipid-containing microalgae culturing mode have been verified. Method of various micro algae heat-treated biomass conversion into biohydrogen by anaerobic acetone-butanol fermentation using cellular immobilized catalysts based on Clostridium acetobutylicum has been considered. Ultimate hydrogen efficiency has been found for Chlorococcum sp. rsemsu Ccc-7/11 strain biomass (8.4 6.1 mmol/1 of medium/day); while hydrogen production is 23.7% and 18.6% of notionally possible level, A. platensis strains cultivated under the influence of stressors (rsemsu 1/02-P - 5.6 mmol/l of medium/day, 32.3%; rsemsu 1/02-T - 3.3 mmol/of medium/day, 28.8%) rank slightly below them in efficiency, outperforming in hydrogen production. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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  30. Microalgal biodiesel: A possible solution for India's energy security
    Abstract

    Sharma, Y. C.; Singh, V. 2017. Microalgal biodiesel: A possible solution for India's energy security. Renewable & Sustainable Energy Reviews. 6772-88

    Extreme accession in industrialization and urbanization is responsible for huge demand of fossil fuels which are depleting day by day. Hence, search for renewable energy resource has become a considerable challenge in recent years. Biodiesel has been recognized as an alternative fuel, non-toxic and biodegradable which is capable to replace the diesel fuel. In developing countries such as India, there is crisis of edible oil and the edible oil is imported to accomplish the-demand. Based on the outline presented, it is observed that search for biodiesel sources should consider the feedstocks that do not require fertile land, do not compete with food crop, help in reduction of greenhouse gas emission as well as decrease the dependency on other nations. So, recently microalgae have emerged to be very auspicious feedstock for production of biodiesel. The present study deals with the systematic analyses of energy demand and GHG emission statistics of various nations as well as all the steps involved in overall process from algal strain selection to biodiesel production. With these challenges, the solutions in biodiesel production from microalgae were also shown. Though, biodiesel is economically viable, more inquisition as well as technological evolvement is required in this direction. To overcome these problems, policies based on usage of bio fuels derived by various nations which encourage biodiesel production, making them rival of conventional energy sources are needed. (C) 2016 Elsevier Ltd. All rights reserved.
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  31. Molecular challenges in microalgae towards cost-effective production of quality biodiesel
    Abstract

    Chung, Y. S.; Lee, J. W.; Chung, C. H. 2017. Molecular challenges in microalgae towards cost-effective production of quality biodiesel. Renewable & Sustainable Energy Reviews. 74139-144

    Based on their environmental benefits, microalgae are currently the most favorable renewable biofeedstock materials for biodiesel production. However, the possibility of an economically viable production system using microalgae is still technology-driven, not yet market-driven due to its higher production cost. Accordingly, to establish industrial manufacturing systems for microalgal biodiesel, it is critical to develop technology for its cost-effective production. Here, we propose some novel molecular strategies, which have not been attempted for microalgal biodiesel production and are conducive to cost-effective production of biodiesel from microalgae. These include genetic manipulation strategies for higher biomass yield and extracellular production of free fatty acids, triacylglycerol, and fatty acid ethyl ester (biodiesel) with high quality, which could be exploited as a breakthrough technology for the cost-efficient production of microalgal biodiesel.
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  32. Molecular Identification and Comparative Evaluation of Tropical Marine Microalgae for Biodiesel Production
    Abstract

    Sabu, S.; Bright Singh, I. S.; Joseph, V. 2017. Molecular Identification and Comparative Evaluation of Tropical Marine Microalgae for Biodiesel Production. Mar Biotechnol (NY). 19(4) 328-344

    Marine microalgae have emerged as important feedstock for liquid biofuel production. The identification of lipid-rich native microalgal species with high growth rate and optimal fatty acid profile and biodiesel properties is the most challenging step in microalgae-based biodiesel production. In this study, attempts have been made to bio-prospect the biodiesel production potential of marine and brackish water microalgal isolates from the west coast of India. A total of 14 microalgal species were isolated, identified using specific molecular markers and based on the lipid content; seven species with total lipid content above 20% of dry cell weight were selected for assessing biodiesel production potential in terms of lipid and biomass productivities, nile red fluorescence, fatty acid profile and biodiesel properties. On comparative analysis, the diatoms were proven to be promising based on the overall desirable properties for biodiesel production. The most potential strain Navicula phyllepta MACC8 with a total lipid content of 26.54 % of dry weight of biomass, the highest growth rate (0.58 day-1) and lipid and biomass productivities of 114 and 431 mgL-1 day-1, respectively, was rich in fatty acids mainly of C16:0, C16:1 and C18:0 in the neutral lipid fraction, the most favoured fatty acids for ideal biodiesel properties. The biodiesel properties met the requirements of fuel quality standards based on empirical estimation. The marine diatoms hold a great promise as feedstock for large-scale biodiesel production along with valuable by-products in a biorefinery perspective, after augmenting lipid and biomass production through biochemical and genetic engineering approaches.
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  33. Oleaginous Microalgae from Dairy Farm Wastewater for Biodiesel Production: Isolation, Characterization and Mass Cultivation
    Abstract

    Sun, Z.; Fang, X. P.; Li, X. Y.; Zhou, Z. G. 2017. Oleaginous Microalgae from Dairy Farm Wastewater for Biodiesel Production: Isolation, Characterization and Mass Cultivation. Appl Biochem Biotechnol.

    Producing biodiesel from microalgae grown in wastewater is environment-friendly and cost-effective. The present study investigated the algae found in wastewater of a local dairy farm for their potential as biodiesel feedstocks. Thirteen native algal strains were isolated. On the basis of morphology and 16S/18S rRNA gene sequences, one strain was identified to be a member of cyanobacteria, while other 12 strains belong to green algae. After screening, two Scenedesmus strains out of the 13 microalgae isolates demonstrated superiority in growth rate, lipid productivity, and sedimentation properties, and therefore were selected for further scale-up outdoor cultivation. Both Scenedesmus strains quickly adapted to the outdoor conditions, exhibiting reasonably good growth and strong anti-contamination capabilities. In flat-plate photobioreactors (PBRs), algal cells accumulated predominantly neutral lipids that accounted for over 60% of total lipids with almost 70% being triacylglycerol. In addition, Scenedesmus obliquus had a high content of monounsaturated fatty acids, of which the amount of oleic acid (C18:1) was up to 27.11%. Based on these findings, the dairy farm wastewater-isolated Scenedesmus strains represent promising sources of low-cost, high-quality oil for biofuel production.
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  34. One-step production of biodiesel from wet and unbroken microalgae biomass using deep eutectic solvent
    Abstract

    Pan, Y.; Alam, M. A.; Wang, Z. M.; Huang, D. L.; Hu, K. Q.; Chen, H. X.; Yuan, Z. H. 2017. One-step production of biodiesel from wet and unbroken microalgae biomass using deep eutectic solvent. Bioresource Technology. 238157-163

    One-step and Two-step methods were studied for lipid extraction from wet and unbroken (water content is 65-67%) Chlorella sp. and Chlorococcum sp. (GN38) using deep eutectic solvent (DES) treated microalgae cells. Further we optimized the extraction process and studied on its underlying mechanism. Among all DES, Choline chloride-Acetic acid (Ch-Aa) DES treatment showed optimal conditions at the mass ratio of DES: methanol-H2SO4 (2.00%) mixture: algae biomass was 60: 40: 3 with reaction time was 60 min, and the optimum temperature was 110 degrees C (Chlorococcum sp.) and 130 degrees C (Chlorella sp.) respectively. The total content of FAME by One-step method with DES treatment was improved by 30% compared with Two-step method. This process is effective on wet and unbroken paste of microalgae biomass, so the FAME extracted using one-step with DES process is feasible for microalgae based biodiesel production. (C) 2017 Elsevier Ltd. All rights reserved.
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  35. Optimization of an effective method for the conversion of crude algal lipids into biodiesel
    Abstract

    Wu, S.; Song, L. R.; Sommerfeld, M.; Hu, Q.; Chen, W. 2017. Optimization of an effective method for the conversion of crude algal lipids into biodiesel. Fuel. 197467-473

    Although microalgae represent a promising alternative feedstock for biofuels, the current solvent-based lipid conversion systems and processes are neither cost-effective nor energy-efficient due to the bad quality of algal crude lipids. In the present study, a novel lipase-catalyzed transesterification method with crude Chlorella lipids was systematically investigated and optimized. A highly efficient conversion protocol with 97% of fatty acid methyl esters (FAME) yield was obtained after the introduction of co-solvent. Then several crucial parameters including the reaction time, molar ratio of algae oils to methanol, ratio of algae oils to co-solvent, ratio of algae oils to lipase and reaction temperature and intensively studied and selected at 12 h, 1: 12, 1: 1 (m/v), 20: 1 (m/m) and 40 degrees C, respectively. In addition, the reusability of the immobilized lipase was also investigated with crude algal lipids. The immobilized lipase could maintain 84% of its original activities even after five recycles. Polar lipid standards along with the polar lipids isolated from crude algal lipids were also tested and results indicated that they could also be converted into biodiesel very efficiently. This study provides an important insight into further decreasing the downstream processing costs in algae-based biofuel production. (C) 2017 Elsevier Ltd. All rights reserved.
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  36. Potential of macroalgae Ulva lactuca as a source feedstock for biodiesel production
    Abstract

    Abd El Baky, H. H.; El Baroty, G. S. 2017. Potential of macroalgae Ulva lactuca as a source feedstock for biodiesel production. Recent Pat Food Nutr Agric.

    BACKGROUND: The aim of this study was to investigate the possibility of growing of algae Ulva lactuca L under different salinity levels coupled with varied KNO3 concentrations (source of N) as a potential source of oil for biodiesel production. METHODS: U. lactuta was cultured in 10.0% NaCl coupled with either 2.5 g/L (S1+ 1N) or 1.0 g/L KNO3 (S1+ 2N) and in 30.0% NaCl coupled with 2.5 g/L (S2+ 1N) or 1.0 g/L KNO3 (S2+ 2N) nutrient medium. Among all algae cultures, biomass (dry weight) and lipid accumulation (total lipid content, TL) were significantly different (P>0.5%), with various degrees. The TL was increased (8.21% to 15.95%, g/100g) by increasing the NaCl % (from 10% to 30%) coupled with the depletion of KNO3 level (from 2.5% to 1%) in culture medium. High lipid content (15.95%) were obtained in S2+ 2N culture, this lipid showed physical (density, viscosity and average molecular weight) and chemical (iodine, acid, saponification and peroxide values) properties suitable for biodiesel production. RESULTS: The fatty acid methyl esters (FAME, biodiesel) prepared by trans-esterifiction reaction under acidic condition were mainly composed of saturated (50.33%), monounsaturated (MUFA, 36.12%) and polyunsaturated (13.55%) esters. C-18:1 was found to be the main MUFA, representing 25.76 % of total FAME. On the other hand, the values of some critical of physiochemical parameter (density, kinematic viscosity, iodine value, acid value and oxidation stability) of biodiesel were found to meet the standards for a high quality biodiesel. CONCLUSION: Hence, U. lactuta could be serving as a valuable renewable biomass of oil for biodiesel production.
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  37. Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities
    Abstract

    Muto, M.; Nojima, D.; Yue, L.; Kanehara, H.; Naruse, H.; Ujiro, A.; Yoshino, T.; Matsunaga, T.; Tanaka, T. 2017. Potential of water surface-floating microalgae for biodiesel production: Floating-biomass and lipid productivities. Journal of Bioscience and Bioengineering. 123(3) 314-318

    Microalgae have been accepted as a promising feedstock for biodiesel production owing to their capability of converting solar energy into lipids through photosynthesis. However, the high capital and operating costs, and high energy consumption, are hampering commercialization of microalgal biodiesel. In this study, the surface-floating microalga, strain AVFF007 (tentatively identified as Botryosphaerella sudetica), which naturally forms a biofilm on surfaces, was characterized for use in biodiesel production. The biofilm could be conveniently harvested from the surface of the water by adsorbing onto a polyethylene film. The lipid productivity of strain AVFF007 was 46.3 ma/L/day, allowing direct comparison to lipid productivities of other microalgal species. The moisture content of the surface-floating biomass was 86.0 +/- 1.2%, which was much lower than that of the biomass harvested using centrifugation. These results reveal the potential of this surface-floating microalgal species as a biodiesel producer, employing a novel biomass harvesting and dewatering strategy. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.
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  38. Pretreated algal bloom as a substantial nutrient source for microalgae cultivation for biodiesel production
    Abstract

    Jain, P.; Arora, N.; Mehtani, J.; Pruthi, V.; Majumder, C. B. 2017. Pretreated algal bloom as a substantial nutrient source for microalgae cultivation for biodiesel production. Bioresource Technology. 242152-160

    In the present investigation, toxic algal bloom, a copious and low-cost nutrient source was deployed for cultivating Chlorella pyrenoidosa. Various pre-treatment methods using combinations of acid/alkali and autoclave/microwave were tested for preparing hydrolysates and compared with minimal media (BG-11). Acid autoclave treatment resulted in maximum carbon, nitrogen and phosphorous content which substantially boosted the growth of the microalgal cells (4.36 g/L) as compared to rest of the media. The microalga grown in this media also showed enhanced lipid content (43.2%) and lipid productivity (188 mg/L/d) as compared to BG-11 (19.42 mg/L/d). The biochemical composition showed 1.6-fold declines in protein while 1.27 folds in carbohydrate content as compared to BG-11. The fatty acid profile revealed the presence of C14-C22 with increased amount of monounsaturated fatty acids as compared to BG-11. The results obtained showed that algal bloom can be used as a potential nutrient source for microalgae. (C) 2017 Elsevier Ltd. All rights reserved.
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  39. Production of biodiesel from microalgae through biological carbon capture: a review
    Abstract

    Mondal, M.; Goswami, S.; Ghosh, A.; Oinam, G.; Tiwari, O. N.; Das, P.; Gayen, K.; Mandal, M. K.; Halder, G. N. 2017. Production of biodiesel from microalgae through biological carbon capture: a review. 3 Biotech. 7

    Gradual increase in concentration of carbon dioxide (CO2) in the atmosphere due to the various anthropogenic interventions leading to significant alteration in the global carbon cycle has been a subject of worldwide attention and matter of potential research over the last few decades. In these alarming scenario microalgae seems to be an attractive medium for capturing the excess CO2 present in the atmosphere generated from different sources such as power plants, automobiles, volcanic eruption, decomposition of organic matters and forest fires. This captured CO2 through microalgae could be used as potential carbon source to produce lipids for the generation of biofuel for replacing petroleum-derived transport fuel without affecting the supply of food and crops. This comprehensive review strives to provide a systematic account of recent developments in the field of biological carbon capture through microalgae for its utilization towards the generation of biodiesel highlighting the significance of certain key parameters such as selection of efficient strain, microalgal metabolism, cultivation systems (open and closed) and biomass production along with the national and international biodiesel specifications and properties. The potential use of photobioreactors for biodiesel production under the influence of various factors viz., light intensity, pH, time, temperature, CO2 concentration and flow rate has been discussed. The review also provides an economic overview and future outlook on biodiesel production from microalgae.
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  40. Production of liquid biofuels (biodiesel and bioethanol) from brown marine macroalgae Padina tetrastromatica
    Abstract

    Ashokkumar, V.; Salim, M. R.; Salam, Z.; Sivakumar, P.; Chong, C. T.; Elumalai, S.; Suresh, V.; Ani, F. N. 2017. Production of liquid biofuels (biodiesel and bioethanol) from brown marine macroalgae Padina tetrastromatica. Energy Conversion and Management. 135351-361

    In this study, an integrated biomass conversion concept of producing liquid biofuels from brown marine macroalga Padina tetrastromatica was investigated. The algal biomass was collected from the Mandapam coastal region and processed under laboratory. Various parameters were studied to extract crude lipids from the biomass. A kinetic study was conducted for extracting the lipids from the biomass, which follows the first order kinetics and the lipid yield was 8.15 wt.%. The activation energy; Ea = 34.314 kJ mol(-1) and their thermodynamic parameters were determined. Since the crude algal lipids contain high amount of free fatty acids, a sequential transesterification technique was examined and 7.8% of biodiesel (78 mg/g algal biomass) yield was obtained. The biodiesel was analyzed by H-1 and C-13-NMR spectroscopy and the conversion yield was estimated. Further, the biodiesel fuel properties were investigated and found that all the features fit the required ASTM D6751 specification limits. The residual biomass after lipid extraction was further explored for bioethanol production through the anaerobic fermentation process. The ethanol yield obtained after saccharification and fermentation were estimated and 161 mg/g residue biomass was reported. The theoretical yield of conversion of hydrolysate to bioethanol was estimated and found to be 83.4%. Therefore, this study demonstrates that macroalga P. tetrastromatica biomass has great potential to produce liquid biofuels such as biodiesel and bioethanol. (C) 2017 Elsevier Ltd. All rights reserved.
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  41. Production of methyl ester from two microalgae by two-step transesterification and direct transesterification
    Abstract

    Sivaramakrishnan, R.; Incharoensakdi, A. 2017. Production of methyl ester from two microalgae by two-step transesterification and direct transesterification. Environmental Science and Pollution Research. 24(5) 4950-4963

    The efficiency of oil extraction from Chlorella sp. and Scenedesmus sp. using different cell disruption and solvent system was investigated. The ultrasound cell disruption method showed the maximum oil extraction in both algae. Oil extraction with hexane resulted in maximum oil yield for both algae. The kinetic parameters were studied and the extraction followed the first-order kinetics. The activation energy and thermodynamic activation parameters were calculated for both microalgae and the results suggested that the extraction was endothermic, irreversible and spontaneous. The methyl ester yields by two-step transesterification and direct transesterification were 95 and 96% for Scenedesmus sp. and 89 and 92% for Chlorella sp. respectively. Both methods had similar net energy consumption suitable for industrial application. The methyl ester properties were analysed in comparison with those of American Society for Testing and Materials (ASTM) D6751 standards.
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  42. Prospects of Applying Microalgal Lipids to Biodiesel Fuel Production
    Abstract

    Sister, V. G.; Ivannikova, E. M.; Nagornov, S. A. 2017. Prospects of Applying Microalgal Lipids to Biodiesel Fuel Production. Chemical and Petroleum Engineering. 53(1-2) 94-100

    Promising biological objects containing the maximum amounts of lipids were selected for further study based on an analysis of published studies on the quantitative and qualitative composition of lipids accumulating in microalgae. The genera Navicula and Isochrysis were found to be most optimal for liquid biofuel production because they contained the maximum percentage of triacylglycerides in the total lipids. Freshwater species of these microalgae genera can be considered most suitable for cultivation in CFD bioreactors as a primary product of biofuel production. Innovative methods using vortex devices are proposed for removing the algal oil.
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  43. Review on algae for biodiesel fuel production, its characteristics comparison with other and their impact on performance, combustion and emissions of diesel engine
    Abstract

    Katam, G. B.; Babu, A. V.; Murthy, K. M.; Warkhade, G. S. 2017. Review on algae for biodiesel fuel production, its characteristics comparison with other and their impact on performance, combustion and emissions of diesel engine. World Journal of Engineering. 14(2) 127-138

    Purpose - This study aims to find a new alternate source for biodiesel conversion. The alternate source must be easily available, and it should give more oil yield than available edible, inedible sources. To meet the fuel demand in the transportation sector with edible oil-based biodiesel causes food versus fuel crisis. In addition to this, it increases NOx and CO2 in the environment.
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  44. The growth characteristics and biodiesel production of ten algae strains cultivated in anaerobically digested effluent from kitchen waste
    Abstract

    Yu, Z.; Song, M. M.; Pei, H. Y.; Han, F.; Jiang, L. Q.; Hou, Q. J. 2017. The growth characteristics and biodiesel production of ten algae strains cultivated in anaerobically digested effluent from kitchen waste. Algal Research-Biomass Biofuels and Bioproducts. 24265-275

    The growth characteristics and biodiesel production of ten algae strains cultivated in diluted anaerobically digested effluent kitchen waste (KWADE) were studied in this paper. Four microalgae species could tolerate the high NH3-N concentration in KWADE. Based on the results of PROMETHEE-GAIA, all strains cultivated with KWADE attained better biodiesel properties compared to cultivation in BG11. The most suitable strain was Scenedesmus SDEC-8, followed by Chlorella SDEC-18 and Scenedesmus SDEC-13. The best strain, Scenedesmus SDEC-8, achieved an extraordinary lipid content of 33.85% and lipid productivity of 20.27 mg L-1 d(-1), a desirable fatty acid methyl ester profile of 94.03% and satisfactory biodiesel properties in cetane number (59.39), iodine value (51.58 gI(2)/100 g fat) and lower cloud point (13.01 degrees C) too. In addition, SDEC-8 also exhibited the highest nitrogen average yield coefficient of 53.1 mg g(-1), and had an average yield coefficient of 1.8 mg g(-1) for phosphorous.
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  45. The prospect of microalgal biodiesel using agro-industrial and industrial wastes in Malaysia
    Abstract

    Jayakumar, S.; Yusoff, M. M.; Ab Rahim, M. H.; Maniam, G. P.; Govindan, N. 2017. The prospect of microalgal biodiesel using agro-industrial and industrial wastes in Malaysia. Renewable & Sustainable Energy Reviews. 7233-47

    The world's biodiesel demand is rising from day to day due to the urgency to tackle fuel crisis, greenhouse gases (GHG) emissions and climatic changes in the near future. This alternative energy will minimize the dependency on fossil fuels while guarantees a continuous energy supply and upholds the ecosystem sustainability. Malaysia, as a developing country is still finding a suitable green energy source to support the national daily energy consumption without affecting the political stability and socio-economic background. In this article, a realistic effort made by applying microalgal biotechnology for biodiesel production and concurrently mitigating CO2 and other flue gases in the presence of tertiary wastewater. Microalgae produce high amount of biomass feedstock in a short time with less amount of land capacity by using wastewater as the medium to grow. Malaysia is producing variable wastes from both agro-industrial and industrial sectors that can be recycled as a nutrient supply for microalgae. Wastewater that is available in Malaysia comprises high nutrient value compounds that have high amount of nitrogen and phosphorus. The current trend in Malaysia in the biodiesel industry as well as the application of microalgae as a superlative feedstock to replace conventional methods and boost future biodiesel industries are well elaborated in this article. This also includes the opportunities and challenges of Malaysia in cultivating microalgae with stronger technical feasibility and higher turnout in the economy by using the high rate algal pond (HRAP). Apart from that, this review paper illustrates the process of converting waste from five different sources in biofuel production by using microalgae as the intermediate tool.
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  46. Ultrasonic Assisted Biodiesel Production of Microalgae by Direct Transesterification
    Abstract

    Kalsum, U.; Mahfud, M.; Roesyadi, A. 2017. Ultrasonic Assisted Biodiesel Production of Microalgae by Direct Transesterification. International Conference on Chemistry, Chemical Process and Engineering (Ic3pe) 2017. 1823

    Microalgae are considered as the third generation source of biofuel and an excellent candidate for biofuel production to replace the fossil energy. The use of ultrasonic in producing biodiesel by direct transesterification of Nannochloropsis occulata using KOH as catalyst and methanol as a solvent was investigated. The following condition were determined as an optimum by experimental evaluates:: 1: 15 microalga to methanol (molar ratio); 3% catalyst concentration at temperature 40 C after 30 minute of ultrasonication. The highest yield of biodiesel produced was 30.3%. The main components of methyl ester from Nannochloropsis occulata were palmitic (C16 :0),, oleic (C18:1); stearic (C18;0); arahidic (C20:0) and myristic (C14:0). This stated that the application of ultrasounic for direct transesterificaiton of microalgae effectively reduced the reaction time compared to the reported values of conventional heating systems.
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  47. Waste-free technology of wastewater treatment to obtain microalgal biomass for biodiesel production
    Abstract

    Zayadan, B. K.; Sadvakasova, A. K.; Usserbayeva, A. A.; Bolatkhan, K.; Baizhigitova, A. M.; Akmukhanova, N. R.; Sidorov, R. A.; Sinetova, M. A.; Los, D. A. 2017. Waste-free technology of wastewater treatment to obtain microalgal biomass for biodiesel production. International Journal of Hydrogen Energy. 42(12) 8586-8591

    Five axenic cultures of microalgae were isolated from the wastewater of Almaty city and identified as Chlorella vulgaris strain No1, Chlorella sp. strain.No3, Scenedesmus obliquus, Phorrnidium foveolarum and Lyngbya limnetica. Among these strains, C. vulgaris strain No1 was characterized by the maximum growth rate and the highest productivity. Mass cultivation of this strain in wastewater resulted in accumulation of 5 x 10(7) cells per ml in 16 days, and in the removal of similar to 95% of pollutants from water. Cells of C. vulgaris consisted of similar to 35% proteins, 29% carbohydrates, 30% lipids, and 6% ash, as calculated on a dry weight basis. The major fatty -acids of C. vulgaris were represented by palmitic, cis-7,10hexadecenoic acid, linoleic, and a-linolenic acids. Culturing in wastewater decreased the unsaturation index of FAs. Thus, C. vulgaris cells are suitable for both waste water purification and accumulation of biomass for further biodiesel production. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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  48. A new approach of microalgal biomass pretreatment using deep eutectic solvents for enhanced lipid recovery for biodiesel production
    Abstract

    Lu, W. D.; Alam, M. A.; Pan, Y.; Wu, J. C.; Wang, Z. M.; Yuan, Z. H. 2016. A new approach of microalgal biomass pretreatment using deep eutectic solvents for enhanced lipid recovery for biodiesel production. Bioresource Technology. 218123-128

    The biomass of Chlorella sp. was pretreated with three different aqueous deep eutectic solvents (aDESs), i.e. aqueous choline chloride-oxalic acid (aCh-O), aqueous choline chloride-ethylene glycol (aCh-EG) and aqueous urea-acetamide (aU-A). The effect of aDESs pretreatment of microalgae biomass was evaluated in terms of lipid recovery rate, total carbohydrate content, fatty acid composition, and thermal chemical behavior of biomass. Results indicated that, lipid recovery rate was increased from 52.03% of untreated biomass to 80.90%, 66.92%, and 75.26% of the biomass treated by aCh-O, aCh-EG and aU-A, respectively. However, there were no major changes observed in fatty acid profiles of both untreated and treated biomass, specifically palmitic acid, palmitoleic acid and stearic acid under various pretreatments. Furthermore, characterizations of untreated and treated biomass were carried out using Fourier transform infrared (FTIR), thermogravimetry analysis (TGA) and scanning electron microscope (SEM) to understand the enhanced lipids recovery. (C) 2016 Published by Elsevier Ltd.
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  49. A novel process on lipid extraction from microalgae for biodiesel production
    Abstract

    Wang, S. M.; Zhu, J.; Dai, L. M.; Zhao, X. B.; Liu, D. H.; Du, W. 2016. A novel process on lipid extraction from microalgae for biodiesel production. Energy. 115963-968

    To promote microbial oils as the feedstock for biodiesel preparation, developing an advanced cell treatment technology, especially suitable for treating water-containing microbial feedstock is very important. A novel method based on using formic acid assisted with small amounts of hydrochloric acid, to treat water-containing microalgae and extract lipid subsequently, is proposed in this paper. Effect of several factors on mixed acid treatment of Chlorella protothecoides was investigated systematically. It was found that the dosage of formic acid and hydrochloric acid, liquid/solid (l/s) ratio and temperature had a significant influence on lipid extraction from water-containing microalgae. Under the optimum condition of formic acid dosage 5.57 g/g (based on the weight of dried microalgae cell, the same below), hydrochloric acid dosage 0.1 g/g, liquid/solid (Vs) ratio10:1 and temperature 100 degrees C, the total lipid yield and FAME (Fatty Acid Methyl Ester) yield reached 45.6% and 85.8% respectively. This process allowed water content of wet biomass reaching 82.1%. Further study revealed that the process was suitable for the treatment of different microalgae materials. The results indicate that this mixed acid treatment is very promising for using wet microalgae as the feedstocks for biodiesel production. (C) 2016 Elsevier Ltd. All rights reserved.
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  50. A robust process for lipase-mediated biodiesel production from microalgae lipid
    Abstract

    Chen, J. Z.; Wang, S. M.; Zhou, B. Y.; Dai, L. M.; Liu, D. H.; Du, W. 2016. A robust process for lipase-mediated biodiesel production from microalgae lipid. Rsc Advances. 6(54) 48515-48522

    Microalgae lipid has been considered a good feedstock for biodiesel production because of its wellrecognized advantages. To promote microalgae as a feedstock for biodiesel production, developing an appropriate method to convert the lipid into biodiesel is significant. A novel process with the combination of free lipase and immobilized lipase used for the conversion of microalgae lipid for biodiesel production is proposed in this paper. The combination of the two lipases was demonstrated to be effective in converting free fatty acids into biodiesel (FAME). The effect of different factors influencing immobilized lipase-catalyzed methanolysis was investigated systematically. It was demonstrated that the strategy of adding methanol, molecular sieve dosage, lipase dosage and temperature had significant influence on the FAME yield. Under the optimized conditions (10% 3 angstrom molecular sieve dosage (w/w), molar ratio of methanol to lipid 5 : 1, lipase dosage 5% (w/w), temperature 45 degrees C and agitation rate 300 rpm), a biodiesel yield of 97% could be obtained. Further, a 5-level-4-factor central composite design was employed to optimize immobilized lipase-mediated alcoholysis and the relationships between the variables and their co-influence on biodiesel yield were further analyzed systematically.
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  51. A sustainable integrated in situ transesterification of microalgae for biodiesel production and associated co-product-a review
    Abstract

    Salam, K. A.; Velasquez-Orta, S. B.; Harvey, A. P. 2016. A sustainable integrated in situ transesterification of microalgae for biodiesel production and associated co-product-a review. Renewable & Sustainable Energy Reviews. 651179-1198

    Microalgae has large scale cultivation history particularly in aquaculture, pigments and nutraceutical production. Despite the advantages of microalgal oil as feedstock for biodiesel production, algal biodiesel is still at laboratory scale due to technical challenges required to be overcome to make it economical and sustainable. Indeed, complete drying of microalgae is energy intensive and significantly increases the cost of algae pre-treatment. In situ transesterification is more water tolerant due to excess methanol to oil molar ratio required by such production route. However, the need to remove unreacted methanol (> 94% of it) from the product streams certainly requires distillation heat load which increases the operating cost. This article reviews the key process variables affecting efficiency of in situ transesterification. These include alcohol to oil molar ratio, moisture, stirring rate, reaction time, temperature, microalgal cell wall and catalyst type. Potential solutions of improving the efficiency/economy are discussed. Overall, an integrated approach of in situ dimethyl ether (DME) production along with the desired biodiesel synthesis during in situ transesterification would substantially reduce the volume of unreacted methanol thereby reduces operating cost. Use of resulting microalgal residue for biogas (methane) production can provide energy for biomass production/separation from the dilute algae-water mixture. Use of bio-digestate as nutrients for supporting microalgal growth is among the probable solutions suggested for reducing the production cost of in situ transesterification. (C) 2016 Elsevier Ltd. All rights reserved.
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  52. Algal Biodiesel in Lithuania: from Promise to Reality
    Abstract

    Felneris, M.; Raslavicius, L. 2016. Algal Biodiesel in Lithuania: from Promise to Reality. Proceedings of the 9th International Scientific Conference (Transbaltica 2015). 134109-113

    The search for alternative fuel sources of organic origin, their adaptation and promotion emerged as one of the key focus areas worldwide, which could bring positive effect on lowering down the fossil fuel prices and solving the environmental problems. Algal biodiesel intended for use in the vehicles is among the solutions for the transport sector. In this article, we made an overview of biodiesel investigation in Lithuania over 11 years. Algae are the third generation biofuel form with high production perspective. This microorganism can be found almost everywhere even in Arctic. Algae can be counted as 55 000 species organism with great number of growth and quantities of biomass per unit. Possibilities and challenges of biodiesel from algae in Lithuania have been analysed. Application and compatibility of algae biodiesel in internal combustion engine has been investigated. Many advantages of biodiesel have been presented as well as some disadvantages were found. (C) 2016 The Authors. Published by Elsevier Ltd.
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  53. Algal Biodiesel Production: Comparison, Characterization and Optimization of Various Extraction Processes
    Abstract

    Verma, B.; Balomajumder, C. 2016. Algal Biodiesel Production: Comparison, Characterization and Optimization of Various Extraction Processes. International Journal of Renewable Energy Research. 6(3) 1071-1075

    The paper presents the production of Algal biodiesel from three processes namely Flask-magnetic Stirrer set up, Soxhlet apparatus and Ultrasonication Technique. The algal sample is identified to be Rhizoclonium heiroglyphicum (C.A.Ag.). The extraction time in case of extraction using ultrasonication technique is minimum which is 50 min followed by 6 hrs in case of flask-magnetic stirrer set up and 12 hrs in case of extraction through soxhlet apparatus. Also the percentage recovery in case extraction through ultrasonication is maximum which is 56.2% followed by 51.43% (Flask magnetic stirrer set up) and 49.52% (soxhlet apparatus). Ultrasonication at 70% amplitude and at 0.7 cycle per sec for extraction time of 50 min proves to be superior among three processes in terms of reduction in time and percentage recovery. Also, FESEM of algae before and after extraction of algal oil has been analyzed.
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  54. Assessment and comparison of the properties of biodiesel synthesized from three different types of wet microalgal biomass
    Abstract

    Gangadhar, K. N.; Pereira, H.; Diogo, H. P.; dos Santos, R. M. B.; Devi, B. L. A. P.; Prasad, R. B. N.; Custodio, L.; Malcata, F. X.; Varela, J.; Barreira, L. 2016. Assessment and comparison of the properties of biodiesel synthesized from three different types of wet microalgal biomass. Journal of Applied Phycology. 28(3) 1571-1578

    In recent years, microalgae-based carbon-neutral biofuels (i.e., biodiesel) have gained considerable interest due to high growth rate and higher lipid productivity of microalgae during the whole year, delivering continuous biomass production as compared to vegetable-based feedstocks. Therefore, biodiesel was synthesized from three different microalgal species, namely Tetraselmis sp. (Chlorophyta) and Nannochloropsis oculata and Phaeodactylum tricornutum (Heterokontophyta), and the fuel properties of the biodiesel were analytically determined, unlike most studies which rely on estimates based on the lipid profile of the microalgae. These include density, kinematic viscosity, total and free glycerol, and high heating value (HHV), while cetane number (CN) and cold filter plugging point (CFPP) were estimated based on the fatty acid methyl ester profile of the biodiesel samples instead of the lipid profile of the microalgae. Most biodiesel properties abide by the ASTM D6751 and the EN 14214 specifications, although none of the biodiesel samples met the minimum CN or the maximum content of polyunsaturated fatty acids with a parts per thousand yen4 double bonds as required by the EN 14214 reference value. On the other hand, bomb calorimetric experiments revealed that the heat of combustion of all samples was on the upper limit expected for biodiesel fuels, actually being close to that of petrodiesel. Post-production processing may overcome the aforementioned limitations, enabling the production of biodiesel with high HHV obtained from lipids present in these microalgae.
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  55. Biodiesel and poly-unsaturated fatty acids production from algae and crop plants - a rapid and comprehensive workflow for lipid analysis
    Abstract

    Furuhashi, T.; Nakamura, T.; Fragner, L.; Roustan, V.; Schon, V.; Weckwerth, W. 2016. Biodiesel and poly-unsaturated fatty acids production from algae and crop plants - a rapid and comprehensive workflow for lipid analysis. Biotechnology Journal. 11(10) 1262-1267

    Fatty acid methyl ester analysis (FAME) by gas chromatography coupled to mass spectrometry (GC-MS) is a widely used technique in biodiesel/bioproduct (e.g. poly-unsaturated fatty acids, PUFA) research but typically does not allow distinguishing between bound and free fatty acids. To understand and optimize biosynthetic pathways, however, the origin of the fatty acid is an important information. Furthermore the annotation of PUFAs is compromised in classical GC-EI-MS because the precursor molecular ion is missing. In the present protocol an alkaline methyl esterification step with TMS derivatization enabling the simultaneous analysis of bound and free fatty acids but also further lipids such as sterols in one GC-MS chromatogram is combined. This protocol is applied to different lipid extracts from single cell algae to higher plants: Chlorella vulgaris, Chlamydomonas reinhardtii, Coffea arabica, Pisum sativum and Cuscuta japonica. Further, field ionization (GC-FI-MS) is introduced for a better annotation of fatty acids and exact determination of the number of double bonds in PUFAs. The proposed workflow provides a convenient strategy to analyze algae and other plant crop systems with respect to their capacity for third generation biodiesel and high-quality bioproducts for nutrition such as PUFAs.
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  56. Biodiesel production from different algal oil using immobilized pure lipase and tailor made rPichia pastoris with Cal A and Cal B genes
    Abstract

    Bharathiraja, B.; Kumar, R. R.; PraveenKumar, R.; Chakravarthy, M.; Yogendran, D.; Jayamuthunagai, J. 2016. Biodiesel production from different algal oil using immobilized pure lipase and tailor made rPichia pastoris with Cal A and Cal B genes. Bioresource Technology. 21369-78

    In this investigation, oil extraction was performed in marine macroalgae Gracilaria edulis, Enteromorpha compressa and Ulva lactuca. The algal biomass was characterized by Scanning Electron Microscopy and Fourier Transform-Infra Red Spectroscopy. Six different pre-treatment methods were carried out to evaluate the best method for maximum oil extraction. Optimization of extraction parameters were performed and high oil yield was obtained at temperature 55 degrees C, time 150 min, particle size 0.10 mm, solvent-to-solid ratio 6: 1 and agitation rate 500 rpm. After optimization, 9.5%, 12.18% and 10.50 (g/g) of oil extraction yield was achieved from the respective algal biomass. The rate constant for extraction was obtained as first order kinetics, by differential method. Stable intracellular Cal A and Cal B lipase producing recombinant Pichia pastoris was constructed and used as biocatalyst for biodiesel production. Comparative analysis of lipase activity and biodiesel yield was made with immobilized Candida antarctica lipase. (C) 2016 Elsevier Ltd. All rights reserved.
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  57. Biodiesel production from microalgae: ionic liquid process simulation
    Abstract

    Piemonte, V.; Di Paola, L.; Iaquaniello, G.; Prisciandaro, M. 2016. Biodiesel production from microalgae: ionic liquid process simulation. Journal of Cleaner Production. 11162-68

    The industrial scale production of biodiesel, the most common biofuel, requires innovative solutions to become more and more competitive with a reduced environmental impact. Microalgae are the most promising feedstock for biodiesel production since they are grown on non-arable areas and reduce the greenhouse gas emissions as well. The oil extraction is the competitiveness bottleneck, largely impacting the overall process cost. Oil extraction using ionic liquids is considered a promising technique, which has the chance to become a benchmark for large scale applications. In this paper a novel process simulation of ionic liquid operation is developed, implemented by Aspen Hysys V7.3. The chosen ionic liquid is Butyl-3-methylimidazolium chloride, a green solvent; since it is a non-conventional compound, a method to compute its properties through a thermodynamic model is provided. Moreover, a process scheme has been set up and simulated, composed of a lysis reactor, in which the ionic liquid is added for oil extraction, and a three phase separator, with recycle lines and several heat exchangers for heat recovery. Mass and energy balances have been carried out. The main results allowed to calculate the recovered oil as a function of the ionic liquid to dry biomass weight ratio (with assuming a bio-oil extraction yield of 100) and as expected, the bio-oil recovery yield increased at decreasing temperature. However, a complete recovery is not feasible, due to the physical constraints in the thermodynamic model hypotheses. Albeit some simplifying hypotheses for the thermodynamic properties, the novelty of this work is that it reports results of a process simulation, providing indication for industrial technological implementation coming from a professional tool for process simulation and control. (C) 2015 Elsevier Ltd. All rights reserved.
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  58. Biodiesel Production from Wastewater Using Oleaginous Yeast and Microalgae
    Abstract

    Ling, J.; de Toledo, R. A.; Shim, H. 2016. Biodiesel Production from Wastewater Using Oleaginous Yeast and Microalgae. Environmental Materials and Waste: Resource Recovery and Pollution Prevention. 179-212

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  59. Biodiesel production from wet microalgae by using graphene oxide as solid acid catalyst
    Abstract

    Cheng, J.; Qiu, Y.; Huang, R.; Yang, W. J.; Zhou, J. H.; Cen, K. F. 2016. Biodiesel production from wet microalgae by using graphene oxide as solid acid catalyst. Bioresource Technology. 221344-349

    In order to produce biodiesel from lipids in wet microalgae with graphene oxide (GO) as solid acid catalyst, the effects on lipids conversion efficiencies of catalyst dosage, transesterification temperature, reaction time, methanol dosage and chloroform dosage were investigated. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis revealed that GO contained 0.997 mmol SO3H groups per gram and high amounts of OH groups. Scanning electron microscopy showed that wet microalgae cells were adsorbed on hydrophilic GO surfaces covered with many OH groups. Lipids extracted by chloroform from microalgal cells were transformed into fatty acids methyl esters (FAMEs) through transesterification catalyzed by the acid centers (SO3H groups) in GO catalysts. The lipids conversion efficiency into FAMEs was 95.1% in microwave-assisted transesterification reactions of 5 wt.% GO catalyst at 90 degrees C for 40 min. (C) 2016 Elsevier Ltd. All rights reserved.
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  60. Biodiesel production potential of mixed microalgal culture grown in domestic wastewater
    Abstract

    Soydemir, G.; Keris-Sen, U. D.; Sen, U.; Gurol, M. D. 2016. Biodiesel production potential of mixed microalgal culture grown in domestic wastewater. Bioprocess and Biosystems Engineering. 39(1) 45-51

    In this study, a mixed microalgal culture grown in secondarily treated domestic wastewater effluent was investigated for biodiesel production using in situ transesterification method with conventional heating. The total lipid content of the mixed culture was found as 26.2 % +/- A 0.6 by weight of dry biomass, and 74 % of the lipids were contributed by total glycerides. In situ transesterification with conventional heating process under acidic conditions produced higher biodiesel yield with chloroform as the co-solvent (82.1 % +/- A 3.9) compared to hexane (55.3 % +/- A 3.9) under the same reaction conditions. The gas chromatography analysis showed that FAME composition was mainly composed of palmitic, palmitoleic, stearic, oleic, linoleic and linolenic acid methyl esters., and thus the mixed microalgal culture fed by domestic wastewaters has had comparable biodiesel conversion yields and FAME composition to mono-culture and pure cultures fed by synthetic culture media. Hence, this study showed that secondarily treated domestic wastewater could potentially be a suitable and sustainable medium for microalgae grown to be used as biodiesel feedstock.
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  61. Biodiesel production potential of wastewater treatment high rate algal pond biomass
    Abstract

    Mehrabadi, A.; Craggs, R.; Farid, M. M. 2016. Biodiesel production potential of wastewater treatment high rate algal pond biomass. Bioresource Technology. 221222-233

    This study investigates the year-round production potential and quality of biodiesel from wastewater treatment high rate algal pond (WWT HRAP) biomass and how it is affected by CO2 addition to the culture. The mean monthly pond biomass and lipid productivities varied between 2.0 +/- 0.3 and 11.1 +/- 2.5 g VSS/m(2)/d, and between 0.5 +/- 0.1 and 2.6 +/- 1.1 g/m(2)/d, respectively. The biomass fatty acid methyl esters were highly complex which led to produce low-quality biodiesel so that it cannot be used directly as a transportation fuel. Overall, 0.9 +/- 0.1 g/m(2)/d (3.2 +/- 0.5 ton/ha/year) low-quality biodiesel could be produced from WWT HRAP biomass which could be further increased to 1.1 +/- 0.1 g/m(2)/d (4.0 ton/ha/year) by lowering culture pH to 6-7 during warm summer months. CO2 addition, had little effect on both the biomass lipid content and profile and consequently did not change the quality of biodiesel. (C) 2016 Published by Elsevier Ltd.
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  62. Bioremediation of domestic and industrial wastewaters integrated with enhanced biodiesel production using novel oleaginous microalgae
    Abstract

    Arora, N.; Patel, A.; Sartaj, K.; Pruthi, P. A.; Pruthi, V. 2016. Bioremediation of domestic and industrial wastewaters integrated with enhanced biodiesel production using novel oleaginous microalgae. Environmental Science and Pollution Research. 23(20) 20997-21007

    The study illustrates the synergistic potential of novel microalgal, Chlamydomonas debaryana IITRIND3, for phycoremediation of domestic, sewage, paper mill and dairy wastewaters and then subsequent utilisation of its biomass for biodiesel production. Among these wastewaters, maximum lipid productivity (87.5 +/- 2.3 mg L-1 day(-1)) was obtained in dairy wastewater with removal efficiency of total nitrogen, total phosphorous, chemical oxygen demand and total organic carbon to be 87.56, 82.17, 78.57 and 85.97 %, respectively. Metal ions such as sodium, calcium, potassium and magnesium were also removed efficiently from the wastewaters tested. Pigment analysis revealed loss of chlorophyll a while increase in carotenoid content in algal cells cultivated in different wastewaters. Biochemical data of microalgae grown in different wastewaters showed reduction in protein content with an increase in carbohydrate and lipid contents. The major fatty acids in algal cells grown in dairy wastewater were C14:0, C16:0, C16:1, C18:0, C18:2 and C18:3. The physical properties of biodiesel derived from microalgae grown in dairy wastewater were in compliance with the ASTM D6751 and EN 14214 fuel standards and were comparable to plant oil methyl esters.
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  63. Boosting TAG Accumulation with Improved Biodiesel Production from Novel Oleaginous Microalgae Scenedesmus sp IITRIND2 Utilizing Waste Sugarcane Bagasse Aqueous Extract (SBAE)
    Abstract

    Arora, N.; Patel, A.; Pruthi, P. A.; Pruthi, V. 2016. Boosting TAG Accumulation with Improved Biodiesel Production from Novel Oleaginous Microalgae Scenedesmus sp IITRIND2 Utilizing Waste Sugarcane Bagasse Aqueous Extract (SBAE). Applied Biochemistry and Biotechnology. 180(1) 109-121

    This investigation utilized sugarcane bagasse aqueous extract (SBAE), a nontoxic, cost-effective medium to boost triacylglycerol (TAG) accumulation in novel fresh water microalgal isolate Scenedesmus sp. IITRIND2. Maximum lipid productivity of 112 +/- 5.2 mg/L/day was recorded in microalgae grown in SBAE compared to modified BBM (26 +/- 3 %). Carotenoid to chlorophyll ratio was 12.5 +/- 2 % higher than in photoautotrophic control, indicating an increase in photosystem II activity, thereby increasing growth rate. Fatty acid methyl ester (FAME) profile revealed presence of C14:0 (2.29 %), C16:0 (15.99 %), C16:2 (4.05 %), C18:0 (3.41 %), C18:1 (41.55 %), C18:2 (12.41), and C20:0 (1.21 %) as the major fatty acids. Cetane number (64.03), cold filter plugging property (-1.05 A degrees C), and oxidative stability (12.03 h) indicated quality biodiesel abiding by ASTM D6751 and EN 14214 fuel standards. Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp. IITRIND2 cultivated in SBAE, aqueous extract made from copious, agricultural waste sugarcane bagasse to increase the lipid productivity, and could further be utilized for cost-effective biodiesel production.
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  64. Comparative analysis of top-lit bubble column and gas-lift bioreactors for microalgae-sourced biodiesel production
    Abstract

    Hosseini, N. S.; Shang, H.; Ross, G. M.; Scott, J. A. 2016. Comparative analysis of top-lit bubble column and gas-lift bioreactors for microalgae-sourced biodiesel production. Energy Conversion and Management. 130230-239

    The development of top-lit one-meter deep bioreactors operated as either a gas-lift or bubble column system using air and carbon dioxide enriched air was studied. The goal was high productivity cultivation of algae with elevated lipid levels suitable for conversion into biodiesel. A theoretical energy requirement analysis and a hydrodynamic model were developed to predict liquid circulation velocities in the gas lift bioreactor, which agreed well with experimental measurements. The influence of operational parameters such as design of bioreactor, gas flow rates and carbon dioxide concentration on the growth and lipid volumetric production of Scenedesmus dimorphus was evaluated using factorial design. While bio-mass productivity was 12% higher in the bubble column bioreactor (68.2 g(dw) m(-2) day(-1)), maximum lipid volumetric production (0.19 g(Lipid) L-1) was found in a gas-lift bioreactor sparged with 6% carbon dioxide due to hydrodynamic and light stresses. (C) 2016 Elsevier Ltd. All rights reserved.
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  65. Comparison of Biodiesel Production by a Supercritical Methanol Method from Microalgae Oil Using Solvent Extraction and Hydrothermal Liquefaction Processes
    Abstract

    Fushimi, C.; Umeda, A. 2016. Comparison of Biodiesel Production by a Supercritical Methanol Method from Microalgae Oil Using Solvent Extraction and Hydrothermal Liquefaction Processes. Energy & Fuels. 30(10) 7916-7922

    The production of biodiesel from bio-oils using two different processes was investigated. The bio-oils were produced via either freeze drying followed by extraction with chloroform/methanol solvents (solvent-extracted oil) or employing a subcritical (573 K, 10 MPa, and 30 min) hydrothermal liquefaction process (HTL oil). Both oils were derived from the diatome Fistulifera solaris JPCC DA0580 and were converted to fatty acid methyl esters (FAMEs) via transesterification/esterification reactions with supercritical methanol (SCM) at relatively mild conditions (593 K and 13 MPa). The impact of the reaction time (10-60 min), methanol/oil molar ratio (42:1 and 21:1), and water content (0-5 wt % based on the weight of the oil) on the FAME yield was investigated. FAME yields from HTL oil (75-80% after 30 min) were higher than corresponding experiments with solvent-extracted oil (48-64% after 30 min) under all investigated conditions. This was attributed to the HTL oil containing more free fatty acids (FFAs), in which SCM promotes the conversion of this oil to FAMEs. Decreasing the ratio of methanol/oil had little impact on the FAME yield from the HTL oil. Adding up to 2.5 wt % water (on the basis of the weight of the oil) to the oil-SCM mixture also had little impact on the FAME yield from either oil. However, adding 5.0 wt % water decreased the FAME yield from both oils, particularly from the solvent-extracted oil.
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  66. Cultivation and harvesting of microalgae in photobioreactor for biodiesel production and simultaneous nutrient removal
    Abstract

    Yang, I. S.; Salama, E. S.; Kim, J. O.; Govindwar, S. P.; Kurade, M. B.; Lee, M.; Roh, H. S.; Jeon, B. H. 2016. Cultivation and harvesting of microalgae in photobioreactor for biodiesel production and simultaneous nutrient removal. Energy Conversion and Management. 11754-62

    Microalgae, Chlorella vulgaris and Scenedesmus obliquus were cultivated in a small scale vertical flat-plate photobioreactor (PBR) supplemented with municipal wastewater in order to achieve simultaneous wastewater treatment and biomass production for biofuel generation. Microalgal growth and nutrient removal including total nitrogen (TN), total phosphorus (TP), total inorganic carbon (TIC) and trace elements (Ca2+, Na+, Mg2+ and Zn2+) were monitored during microalgae cultivation. C. vulgaris and S. obliquus showed optimal specific growth rates (mu(opt)) of 1.39 and 1.41 day(-1), respectively, and the TN and TP were completely removed (>99%) from the wastewater within 8 days. Microalgal biomass in the PBR was harvested using a natural flocculant produced from Moringa oleifera seeds. The harvesting efficiency of M. oleifera was 81% for C. vulgaris and 92% for S. obliquus. The amounts of saturated, monounsaturated, and poly-unsaturated fatty acids in the harvested biomass accounted for 18.66%, 71.61% and 9.75% for C. vulgaris and 28.67%, 57.14% and 11.15% for S. obliquus, respectively. The accumulated fatty acids were suitable to produce high quality biodiesel with characteristics equivalent to crop seeds oil-derived biodiesel. This study demonstrates the potential of microalgae-based biodiesel production through the coupling of advanced wastewater treatment with microalgae cultivation for low-cost biomass production in a PBR. (c) 2016 Elsevier Ltd. All rights reserved.
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  67. Cultivation of Three Microalgae Strains under Mixotrophic Conditions for Biodiesel Production
    Abstract

    Rios, L. F.; Soares, C. D.; Tasic, M. B.; Maciel, M. R. W.; Maciel, R. 2016. Cultivation of Three Microalgae Strains under Mixotrophic Conditions for Biodiesel Production. 2nd International Conference on Biomass (Iconbm 2016). 50409-414

    Microalgal biomass have a potential to be used as feedstock for biodiesel production because of high photosynthetic rates, high biomass production, faster growth in comparison to traditional feedstocks and to not be competitive with food production. In this paper, the growth and lipid content of three microalgae strains, namely Chorella vulgaris, Desmodesmus sp. and Desmodesmus brasiliensis, were studied during 9 days of mixotrophic cultivation. The laboratory scale experiments were carried out in BG-11 media enriched with 10 g/L glucose at initial medium pH of 7.5, temperature of 26 +/- 4 degrees C and light flux of 62 mu E m(-2) s(-1). The highest biomass concentration of 3.82 mg/mL was found in the Desmodesmus brasiliensis, followed with 3.64 mg/mL of Desmodesmus sp. and 3.32 mg/mL of Chorella vulgaris strain. However, the Desmodesmus brasiliensis had the lowest lipid content of 6%, followed with 13.2% of Chorella vulgaris, whereas the Desmodesmus sp. strain produced the highest lipids (19.45%).
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  68. Culture modes and financial evaluation of two oleaginous microalgae for biodiesel production in desert area with open raceway pond
    Abstract

    He, Q. N.; Yang, H. J.; Hu, C. X. 2016. Culture modes and financial evaluation of two oleaginous microalgae for biodiesel production in desert area with open raceway pond. Bioresource Technology. 218571-579

    Cultivation modes of autotrophic microalgae for biodiesel production utilizing open raceway pond were analyzed in this study. Five before screened good microalgae were tested their lipid productivity and biodiesel quality again in outdoor 1000 L ORP. Then, Chlorella sp. L1 and Monoraphidium dybowskii Y2 were selected due to their stronger environmental adaptability, higher lipid productivity and better biodiesel properties. Further scale up cultivation for two species with batch and semi-continuous culture was conducted. In 40,000 L ORP, higher lipid productivity (5.15 versus 4.06 g m(-2) d(-1) for Chlorella sp. L1, 5.35 versus 3.00 g m(-2) d(-1) for M. dybowskii Y2) was achieved in semi-continuous mode. Moreover, the financial costs of 14.18 $ gal(-1) and 13.31 $ gal(-1) for crude biodiesel in two microalgae with semi-continuous mode were more economically feasible for commercial production on large scale outdoors. (C) 2016 Elsevier Ltd. All rights reserved.
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  69. Cyclic pressurization assisted extraction of lipids from microalgae for biodiesel production: Non-equilibrium and equilibrium data
    Abstract

    Batista, G.; Surek, G. A. S.; Beninca, C.; Corazza, M. L.; Zanoelo, E. F. 2016. Cyclic pressurization assisted extraction of lipids from microalgae for biodiesel production: Non-equilibrium and equilibrium data. Fuel. 163133-138

    The extraction of lipids from a microalgae (Chlorella pyrenoidosa) was experimentally investigated at a constant temperature of 30 degrees C with ethanol. The experiments involved a bed of dry solids loaded in a cylindrical vessel with approximately 23.5 x 10(-3) kg of solvent. At the top of the cylinder there was a moving piston to allow extraction at cyclic or constant pressurization. A set of 10 kinetic extraction experiments was performed by varying the solid-liquid feed ratio at 5 levels under atmospheric pressure (91.4 kPa) and cyclic pressurization (300 s at 91.4 kPa + 300 s at 200 kPa per cycle) for 25,200 s (5(1) x 2(1) = 10). At p <= 0.1 a significant statistical effect of cyclic pressurization and solid-solvent ratio on mass fraction of extracted lipid at equilibrium (y(Ae)) was observed, while the influence of pressure at cyclic pressurization on the same response was negligible. y(Ae) was a parameter of a reliable first-order kinetic model tuned on different extraction curves involving a full set of almost 500 experimental kinetic data. Based on these equilibrium data, the highest yield and efficiency of lipid extraction were 11.3% d. b. and 72%, respectively. The slopes of tie lines in rectangular equilibrium diagrams of Ponchon-Savarit for extraction at atmospheric pressure and cyclic pressurization confirm that lipids in microalgae are not easily removed from the insoluble solid. The fraction of microalgae lipids converted to biodiesel by an esterification reaction based on the method of Hartman and Lago was approximately 89 +/- 7%. (C) 2015 Elsevier Ltd. All rights reserved.
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  70. Decolorization improves the fuel properties of algal biodiesel from Isochrysis sp.
    Abstract

    O'Neil, G. W.; Knothe, G.; Williams, J. R.; Burlow, N. P.; Reddy, C. M. 2016. Decolorization improves the fuel properties of algal biodiesel from Isochrysis sp.. Fuel. 179229-234

    Results from the comprehensive fuel testing according to American Society for Testing and Materials International (ASTM) standards of an alkenone-free and decolorized biodiesel produced from the industrially grown marine microalgae Isochrysis sp. are presented. Fatty acid methyl ester (FAME) profiles of the non-decolorized and subsequently decolorized biodiesel fuels were nearly identical, yet the fuel properties were remarkably different. Significant positive impacts on the cetane number, kinematic viscosity, and lubricity were observed, indicating a potential deleterious effect of pigments like chlorophylls and pheophytins on these fuel properties. The decolorization process using montmorillonite K10 gave on average 90% mass recovery, and allowed for an otherwise unobtainable cloud point determination. Oxidative stability of the decolorized Isochrysis biodiesel remained well below the minimum prescribed in biodiesel standards due to elevated content of highly polyunsaturated fatty acids, however other values were in the range of those prescribed in the ASTM standards. Overall, decolorization improved the fuel properties of biodiesel from Isochrysis and may provide a path toward improved biodiesel fuels from other algal species. (C) 2016 Elsevier Ltd. All rights reserved.
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  71. Developments and challenges in biodiesel production from microalgae: A review
    Abstract

    Taparia, T.; Manjari, M. V. S. S.; Mehrotra, R.; Shukla, P.; Mehrotra, S. 2016. Developments and challenges in biodiesel production from microalgae: A review. Biotechnology and Applied Biochemistry. 63(5) 715-726

    The imminent depletion of fossil fuels and the surging global demand for renewable energy have led to the search for nonconventional energy sources. After a few decades of trial and error, the world is now testing the sources of the third generation of fossil fuels, which contain for most parts microalgae. With more than 80% oil content, being adaptable in growth parameters and highly versatile, microalgae are highly promising sources of biofuels in the present time. The present article makes a sweeping attempt to highlight the various methods employed for cultivation of microalgae, techniques to harvest and extract biomass from huge algal cultures, as well as their downstream production and processing procedures. The advantages, limitations, and challenges faced by each of them have been described to some extent. Major concerns pertaining to biofuels are supposed to be their environmental sustainability and economic viability along with their cost effectiveness. This would require a great deal of empirical data on existing systems and a great deal of optimization to generate a more robust one. We have concluded our article with a SWOT analysis of using algae for biodiesel production in a tabulated form. (C) 2015 International Union of Biochemistry and Molecular Biology, Inc.
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  72. Developments and challenges in biodiesel production from microalgae: A review
    Abstract

    Taparia, T.; Mvss, M.; Mehrotra, R.; Shukla, P.; Mehrotra, S. 2016. Developments and challenges in biodiesel production from microalgae: A review. Biotechnol Appl Biochem. 63(5) 715-726

    The imminent depletion of fossil fuels and the surging global demand for renewable energy have led to the search for nonconventional energy sources. After a few decades of trial and error, the world is now testing the sources of the third generation of fossil fuels, which contain for most parts microalgae. With more than 80% oil content, being adaptable in growth parameters and highly versatile, microalgae are highly promising sources of biofuels in the present time. The present article makes a sweeping attempt to highlight the various methods employed for cultivation of microalgae, techniques to harvest and extract biomass from huge algal cultures, as well as their downstream production and processing procedures. The advantages, limitations, and challenges faced by each of them have been described to some extent. Major concerns pertaining to biofuels are supposed to be their environmental sustainability and economic viability along with their cost effectiveness. This would require a great deal of empirical data on existing systems and a great deal of optimization to generate a more robust one. We have concluded our article with a SWOT analysis of using algae for biodiesel production in a tabulated form.
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  73. Eco-design and evaluation for production of 7-aminocephalosporanic acid from carbohydrate wastes discharged after microalgae-based biodiesel production
    Abstract

    Park, C.; Heo, K.; Oh, S.; Kim, S. B.; Lee, S. H.; Kim, Y. H.; Kim, Y.; Lee, J.; Han, S. O.; Lee, S. W.; Kim, S. W. 2016. Eco-design and evaluation for production of 7-aminocephalosporanic acid from carbohydrate wastes discharged after microalgae-based biodiesel production. Journal of Cleaner Production. 133511-517

    The production process of 7-aminocephalosporanic acid (7-ACA) was designed, and green microalgae, Chlorella vulgaris, was used as the raw material for its production. After the oil extraction of C. vulgaris, the waste carbohydrates were utilized by Acremonium chrysogenum M35 as the carbon source to produce cephalosporin C (CPC). An adsorption process using a nonionic resin was designed for the purification of CPC. The resulting CPC was converted to 7-ACA, which was later purified by crystallization. The feasibility of the production process was evaluated by the economics and productivity, and factorial design was used as the statistical investigation of the significance of the factors. The results of the factorial design in this study indicate that the factors such as the carbohydrates quantity and CPC yield in the fermentation were significant for the production of 7-ACA, and the P-IYF (Process for the production of 7-ACA by increasing the fermentation yield) showed the best economic indices except P-SA (Process for the production of 7-ACA by a statistical analysis) among all the designed processes. (C) 2016 Elsevier Ltd. All rights reserved.
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  74. Effect of Solvent on the Extraction of Microalgae Lipid for Biodiesel Production
    Abstract

    Kuan, D. Y.; Du, W.; Dai, L. M.; Ma, G. J.; Liu, D. H. 2016. Effect of Solvent on the Extraction of Microalgae Lipid for Biodiesel Production. Chemical Research in Chinese Universities. 32(4) 625-629

    The effect of solvent on the microalgae lipid extraction was studied. The efficiency of lipid extraction from microalgae was found to differ according to the solvent used. The existence of formic acid contributed to the extraction of lipid to a great extent. With 8 mg/L formic acid existing in the system, the lipid yield and free fatty methyl ester(FAME) yield increased from 39% to 42% and from 81% to 90% respectively compared to those of the control. The highest lipid yield of 42% was achieved from Chlorella protothecoidesis with an FAME yield of 89% when a mixed solvent of 14 mL/g dichloromethane, 2 mL/g methanol and 4 mL/g formic acid was used.
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  75. Energy aspects of microalgal biodiesel production
    Abstract

    Martinez-Guerra, E.; Gude, V. G. 2016. Energy aspects of microalgal biodiesel production. Aims Energy. 4(2) 347-362

    Algal biodiesel production will play a significant role in sustaining future transportation fuel supplies. A large number of researchers around the world are investigating into making this process sustainable by increasing the energy gains and by optimizing resource-utilization efficiencies. Although, research is being pursued aggressively in all aspects of algal biodiesel production from microalgal cell cultivation, cell harvesting, and extraction and transesterification steps to the final product separation and purification, there is a large disparity in the data presented in recent reports making it difficult to assess the real potential of microalgae as a future energy source. This article discusses some of the key issues in energy consumption in the process of algal biodiesel production and identifies the areas for improvement to make this process energy-positive and sustainable.
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  76. Enhanced algal-based treatment of petroleum produced water and biodiesel production
    Abstract

    Talebi, A. F.; Dastgheib, S. M. M.; Tirandaz, H.; Ghafari, A.; Alaie, E.; Tabatabaei, M. 2016. Enhanced algal-based treatment of petroleum produced water and biodiesel production. Rsc Advances. 6(52) 47001-47009

    Millions of barrels of produced water (PW) are generated on a daily basis in petroleum-rich regions around the world. A locally isolated microalgal strain identified as Dunaliella salina was used to treat PW herein. The results showed that the application of the PW increased biomass production and lipid content by approximately 120 and 65% compared to the control (sea water), respectively. Consequently, significantly higher lipid productivity values (2-3.6 times) were achieved using the cultures enriched by different ratios of seawater and PW (1 : 1 to 3 : 1). Moreover, bioprospection by FAME profiling revealed that the inclusion of PW in the culture media altered some properties of the resultant biodiesel. More specifically, cold flow properties were improved by PW enrichment while oxidative stability was deteriorated. From the bioremediation point of view, the studied marine strain, D. salina coped well with the salinity fluctuations in wastewater and was found to be highly capable of removing nitrogen, by 65% and phosphorus, by 40%. Biosorption of toxic heavy metal pollutants such as Ni and Zn were also achieved at rates of approximately 90 and 80%, respectively. Overall, the integrated strategy presented herein seems very promising in minimizing the operating expenses of PW treatment while concurrently offering a sustainable platform to improve algal biodiesel production both in terms of quantity and quality.
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  77. Evaluation of different solvent mixtures in esterifiable lipids extraction from microalgae Botryococcus braunii for biodiesel production
    Abstract

    Hidalgo, P.; Ciudad, G.; Navia, R. 2016. Evaluation of different solvent mixtures in esterifiable lipids extraction from microalgae Botryococcus braunii for biodiesel production. Bioresource Technology. 201360-364

    Non-polar and polar solvents as well as their mixtures were tested for the extraction of microalgae lipids and thus, to evaluate their effect on total and esterifiable lipids extraction yields with potential to be converted to biodiesel. The obtained results show an increase in lipids and esterifiable lipids extraction yields when non-polar and polar solvent mixtures were used. The higher esterifiable lipids extraction yield was 19.2% wt (based on dry biomass) using a chloroform-methanol mixture (75% v/v of methanol), corresponding to a 98.9% wt esterifiable lipids extraction. In addition, esterifiable lipids extraction yield of 18.9% wt (based on dry biomass) was obtained when a petroleum ether-methanol mixture (75% v/v of methanol) was used, corresponding to a 96.9% wt esterifiable lipids extraction. (C) 2015 Elsevier Ltd. All rights reserved.
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  78. Evaluation of hydrolysis-esterification biodiesel production from wet microalgae
    Abstract

    Song, C. F.; Liu, Q. L.; Ji, N.; Deng, S.; Zhao, J.; Li, S. H.; Kitamura, Y. 2016. Evaluation of hydrolysis-esterification biodiesel production from wet microalgae. Bioresource Technology. 214747-754

    Wet microalgae hydrolysis-esterification route has the advantage to avoid the energy-intensive units (e.g. drying and lipid extraction) in the biodiesel production process. In this study, techno-economic evaluation of hydrolysis-esterification biodiesel production process was carried out and compared with conventional (usually including drying, lipid extraction, esterification and transesterification) biodiesel production process. Energy and material balance of the conventional and hydrolysis-esterification processes was evaluated by Aspen Plus. The simulation results indicated that drying (2.36 MJ/L biodiesel) and triolein transesterification (1.89 MJ/L biodiesel) are the dominant energy-intensive stages in the conventional route (5.42 MJ/L biodiesel). By contrast, the total energy consumption of hydrolysis-esterification route can be reduced to 1.81 MJ/L biodiesel, and approximately 3.61 MJ can be saved to produce per liter biodiesel. (C) 2016 Elsevier Ltd. All rights reserved.
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  79. Evidence of thermo and halotolerant Nannochloris isolate suitable for biodiesel production in Qatar Culture Collection of Cyanobacteria and Microalgae
    Abstract

    Saadaoui, I.; Al Ghazal, G.; Bounnit, T.; Al Khulaifi, F.; Al Jabri, H.; Potts, M. 2016. Evidence of thermo and halotolerant Nannochloris isolate suitable for biodiesel production in Qatar Culture Collection of Cyanobacteria and Microalgae. Algal Research-Biomass Biofuels and Bioproducts. 1439-47

    The isolation of autochthonous microalgae, with high lipid-contents and biomass productivities is a crucial aspect of the development of commercial production of microalgae-based biodiesel as well as food security in landlocked locales. This is especially important for deployments in climates such as are found in Qatar, a peninsula in the west Arabian Gulf, which is characterized by an extreme desert climate. 53 autochthonous strains of microalgae were isolated from various freshwater, marine and terrestrial environments in Qatar that led to the establishment of the Qatar University Culture Collection of Cyanobacteria and Microalgae (QUCCCM). Strains were identified via ribotyping and characterized in terms of growth rate and lipid production. 13 different known genera were identified, with the distribution analysis showing Chlorella as the most abundant freshwater known genus (22.64%), followed by Chlorocystis (13.21%). Furthermore, several novel strains were identified. Growth rate analysis evidenced a thermo and halotolerant Nannochloris isolate QUCCCM31 that is able to tolerate 45 degrees C and wide salinity range 35-100 ppt. Determination of lipid content and lipid profiling indicated the presence of promising strains for biodiesel production such as Nannochloris sp. (strain QUCCCM31) with a promising FAME profile for biodiesel production. This strain also produced nervonic acid, a C24:1 straight chain fatty acid of high pharmaceutical potential. (C) 2016 Elsevier B.V. All rights reserved.
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  80. Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass
    Abstract

    O'Neil, G. W.; Williams, J. R.; Wilson-Peltier, J.; Knothe, G.; Reddy, C. M. 2016. Experimental Protocol for Biodiesel Production with Isolation of Alkenones as Coproducts from Commercial Isochrysis Algal Biomass. Jove-Journal of Visualized Experiments. (112)

    The need to replace petroleum fuels with alternatives from renewable and more environmentally sustainable sources is of growing importance. Biomass-derived biofuels have gained considerable attention in this regard, however first generation biofuels from edible crops like corn ethanol or soybean biodiesel have generally fallen out of favor. There is thus great interest in the development of methods for the production of liquid fuels from domestic and superior non-edible sources. Here we describe a detailed procedure for the production of a purified biodiesel from the marine microalgae Isochrysis. Additionally, a unique suite of lipids known as polyunsaturated long-chain alkenones are isolated in parallel as potentially valuable coproducts to offset the cost of biodiesel production. Multi-kilogram quantities of Isochrysis are purchased from two commercial sources, one as a wet paste (80% water) that is first dried prior to processing, and the other a dry milled powder (95% dry). Lipids are extracted with hexanes in a Soxhlet apparatus to produce an algal oil ("hexane algal oil") containing both traditional fats (i.e., triglycerides, 46-60% w/w) and alkenones (16-25% w/w). Saponification of the triglycerides in the algal oil allows for separation of the resulting free fatty acids (FFAs) from alkenone-containing neutral lipids. FFAs are then converted to biodiesel (i.e., fatty acid methyl esters, FAMEs) by acid-catalyzed esterification while alkenones are isolated and purified from the neutral lipids by crystallization. We demonstrate that biodiesel from both commercial Isochrysis biomasses have similar but not identical FAME profiles, characterized by elevated polyunsaturated fatty acid contents (approximately 40% w/w). Yields of biodiesel were consistently higher when starting from the Isochrysis wet paste (12% w/w vs. 7% w/w), which can be traced to lower amounts of hexane algal oil obtained from the powdered Isochrysis product.
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  81. Exploration of upstream and downstream process for microwave assisted sustainable biodiesel production from microalgae Chlorella vulgaris
    Abstract

    Sharma, A. K.; Sahoo, P. K.; Singhal, S.; Joshi, G. 2016. Exploration of upstream and downstream process for microwave assisted sustainable biodiesel production from microalgae Chlorella vulgaris. Bioresource Technology. 216793-800

    The present study explores the integrated approach for the sustainable production of biodiesel from Chlorella vulgaris microalgae. The microalgae were cultivated in 10 m(2) open raceway pond at semi-continuous mode with optimum volumetric and areal production of 28.105 kg/L/y and 71.51 t/h/y, respectively. Alum was used as flocculent for harvesting the microalgae and optimized at different pH. Lipid was extracted using chloroform: methanol (2: 1) and having 12.39% of FFA. Effect of various reaction conditions such as effect of catalyst, methanol: lipid ratio, reaction temperature and time on biodiesel yields were studied under microwave irradiation; and 84.01% of biodiesel yield was obtained under optimized reaction conditions. A comparison was also made between the biodiesel productions under conventional heating and microwave irradiation. The synthesized biodiesel was characterized by H-1 NMR, C-13 NMR, FTIR and GC; however, fuel properties of biodiesel were also studied using specified test methods as per ASTM and EN standards. (C) 2016 Elsevier Ltd. All rights reserved.
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  82. Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification
    Abstract

    Lopez, E. N.; Medina, A. R.; Moreno, P. A. G.; Cerdan, L. E.; Grima, E. M. 2016. Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification. Bioresource Technology. 216904-913

    In order to obtain microalgal saponifiable lipids (SLs) fractions containing different polar lipid (glycolipids and phospholipids) contents, SLs were extracted from wet Nannochloropsis gaditana microalgal biomass using seven extraction systems, and the polar lipid contents of some fractions were reduced by low temperature acetone crystallization. We observed that the polar lipid content in the extracted lipids depended on the polarity of the first solvent used in the extraction system. Lipid fractions with polar lipid contents between 75.1% and 15.3% were obtained. Some of these fractions were transformed into fatty acid methyl esters (FAMEs, biodiesel) by methanolysis, catalyzed by the lipases Novozym 435 and Rhizopus oryzae in tert-butanol medium. We observed that the reaction velocity was higher the lower the polar lipid content, and that the final FAME conversions achieved after using the same lipase batch to catalyze consecutive reactions decreased in relation to an increase in the polar lipid content. (C) 2016 Elsevier Ltd. All rights reserved.
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  83. Fatty acid methyl ester production from wet microalgal biomass by lipase-catalyzed direct transesterification
    Abstract

    Lopez, E. N.; Medina, A. R.; Cerdan, L. E.; Moreno, P. A. G.; Sanchez, M. D. M.; Grima, E. M. 2016. Fatty acid methyl ester production from wet microalgal biomass by lipase-catalyzed direct transesterification. Biomass & Bioenergy. 936-12

    The aim of this work was to optimize the production of fatty acid methyl ester (FAME, biodiesel) from wet Nannchloropsis gaditana microalgal biomass by direct enzymatic transesterification. This was done in order to avoid the high cost associated with the prior steps of drying and oil extraction. Saponifiable lipids (SLs) from microalgal biomass were transformed to FAME using the lipase Novozyme 435 (N435) from Candida antarctica as the catalyst, and finally the FAME were extracted with hexane. t-Butanol was used as the reaction medium so as to decrease lipase deactivation and increase mass transfer velocity. A FAME conversion of 99.5% was achieved using wet microalgal biomass homogenized at 140 MPa to enhance cell disruption, a N435: oil mass ratio of 0.32, methanol added in 3 stages to achieve a total of 4.6 cm(3) g(-1) of oil and 7.1 cm(3) g(-1) oil of added t-butanol, with a reaction time of 56 h. The FAME conversion decreased to 57% after catalyzing three reactions with the same lipase batch. This work shows the influence of the polar lipids contained in the microalgal biomass both on the reaction velocity and on lipase activity. (C) 2016 Elsevier Ltd. All rights reserved.
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  84. Fractionation and Lipase-catalyzed Conversion of Microalgal Lipids to Biodiesel
    Abstract

    Kim, S. W.; Xiao, M.; Shin, H. J. 2016. Fractionation and Lipase-catalyzed Conversion of Microalgal Lipids to Biodiesel. Biotechnology and Bioprocess Engineering. 21(6) 743-750

    This study was conducted to evaluate the lipid fractionation and purification procedures of lipase-catalyzed conversion of neutral lipids to microalgal biodiesel. Microalgae lipids were efficiently recovered and purified by a combined extraction method and crude lipid extracts were separated into neutral lipids, glycolipids, and phospholipids by solid-phase extraction. The high purity of the neutral lipids fraction was confirmed by its low concentration of phosphorous (< 2.0 ppm). Transesterification was catalyzed by immobilized Candida antarctica lipase for 72 h with stepwise addition of methanol. The reaction displayed Michaelis-Menten kinetics and produced high yields of microalgal biodiesel (91.2% in the case of Dunaliella salina) with a high content of unsaturated fatty acids (81.5%). Neutral lipids were converted to biodiesel by three-step transesterification, while the removal of polar lipids maintained the activity of the immobilized lipase by reducing both reaction mixture viscosity and contamination risk.
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  85. Greenhouse gas emissions and energy balance of biodiesel production from microalgae cultivated in photobioreactors in Denmark: a life-cycle modeling
    Abstract

    Monari, C.; Righi, S.; Olsen, S. I. 2016. Greenhouse gas emissions and energy balance of biodiesel production from microalgae cultivated in photobioreactors in Denmark: a life-cycle modeling. Journal of Cleaner Production. 1124084-4092

    The current use of fossil fuels is problematic for both environmental and economic reasons and biofuels are regarded as a potential solution to current energy issues. This study analyzes the energy balances and greenhouse gas emissions of 24 different technology scenarios for the production of algal biodiesel from Nannochloropsis cultivated at industrial scale in photobioreactors in Denmark. Both consolidated and pioneering technologies are analyzed focusing on strengths and weaknesses which influence the performance. Based on literature data, energy balance and greenhouse gas emissions are determined in a comparative 'well-to-tank' Life Cycle Assessment against fossil diesel. Use of by-products from biodiesel production such as glycerol obtained from transesterification and anaerobic digestion of residual biomass are included. Different technologies and methods are considered in cultivation stage (freshwater vs. wastewater; synthetic CO2 vs. waste CO2), harvesting stage (flocculation vs. centrifugation) and oil extraction stage (hexane extraction vs. supercritical CO2 extraction). The choices affecting environmental performance of the scenarios are evaluated. Results show that algal biodiesel produced through current conventional technologies has higher energy demand and greenhouse gas emissions than fossil diesel. However, greenhouse gas emissions of algal biodiesel can be significantly reduced through the use of 'waste' flows (nutrients and CO2) but there are still technical difficulties with both microalgae cultivation in wastewater as well as transportation and injection of waste CO2. In any way, a positive energy balance is still far from being achieved. Considerable improvements must be made to develop an environmentally beneficial microalgae biodiesel production on an industrial scale. In particular, different aspects of cultivation need to be enhanced, such as the use of wastewater and CO2-rich flue gas from industrial power plants. (C) 2015 Elsevier Ltd. All rights reserved.
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  86. High biomass producers and promising candidates for biodiesel production from microalgae collection IBASU-A (Ukraine)
    Abstract

    Tsarenko, P.; Borysova, O.; Blume, Y. 2016. High biomass producers and promising candidates for biodiesel production from microalgae collection IBASU-A (Ukraine). Oceanological and Hydrobiological Studies. 45(1) 79-85

    A comparative study was carried out on the growth characteristics of 33 strains of 12 species belonging to genera Acutodesmus (7), Botryococcus (1), Chlorella (5), Chloroidium (2), Desmodesmus (8), Euglena (2), Monoraphidium (2), and Parachlorella (6) from the Microalgae Culture Collection of the Institute of Botany, NAS of Ukraine (IBASU-A). All high biomass-producing strains considered as promising candidates for biofuel production demonstrated active growth (high maximum cell concentration, specific growth rate and productivity). The most promising strains included Acutodesmus dimorphus IBASU-A 251, 252, Desmodesmus magnus IBASU-A 401, D. multivariabilis var. turskensis IBASU-A 398, Chlorella vulgaris IBASU-A 189, 192, and Parachlorella kessleri IBASU-A 444. Their productivity varied from 0.58 g d.w. l(-1) to 1.6 g d.w. l(-1) per day. In general, the cultivation of these strains is considered both as a potential bioresource of feedstock for biodiesel production and other industrial demands.
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  87. Improvement in lipids extraction processes for biodiesel production from wet microalgal pellets grown on diammonium phosphate and sodium bicarbonate combinations
    Abstract

    Shah, S. H.; Raja, I. A.; Mahmood, Q.; Pervez, A. 2016. Improvement in lipids extraction processes for biodiesel production from wet microalgal pellets grown on diammonium phosphate and sodium bicarbonate combinations. Bioresource Technology. 214199-209

    Biomass productivity and growth kinetics for microalgae grown on sodium bicarbonate and diammonium phosphate were investigated. Different carbon and nitrogen ratios have shown different growth rates and biomass productivity and C:N ratio 50:10 as mg L-1 has shown the best production than all. For effective lipids extraction from biomass thermolysis and sonolysis were carried out from wet biomass. Sonolysis at 2.3 W intensity for 5 min has released 8.58 mg at neutral pH. More quantity of lipids was extracted when extraction was made at pH 4 and 10 which resulted 9 mg and 9.28 mg lipids respectively. Thermal treatment at 100 degrees C for 10 min has released 12.82 mg lipid at neutral pH. In the same thermolysis at pH 4 and 10 more quantity of lipids was extracted which were 15.16 mg and 14.81 mg respectively. Finally transesterified lipids were analyzed through GC-MS for FAME composition analysis. (C) 2016 Elsevier Ltd. All rights reserved.
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  88. Isolation of a euryhaline microalgal strain, Tetraselmis sp CTP4, as a robust feedstock for biodiesel production
    Abstract

    Pereira, H.; Gangadhar, K. N.; Schulze, P. S. C.; Santos, T.; de Sousa, C. B.; Schueler, L. M.; Custodio, L.; Malcata, F. X.; Gouveia, L.; Varela, J. C. S.; Barreira, L. 2016. Isolation of a euryhaline microalgal strain, Tetraselmis sp CTP4, as a robust feedstock for biodiesel production. Scientific Reports. 6

    Bioprospecting for novel microalgal strains is key to improving the feasibility of microalgae-derived biodiesel production. Tetraselmis sp. CTP4 (Chlorophyta, Chlorodendrophyceae) was isolated using fluorescence activated cell sorting (FACS) in order to screen novel lipid-rich microalgae. CTP4 is a robust, euryhaline strain able to grow in seawater growth medium as well as in non-sterile urban wastewater. Because of its large cell size (9-22 mu m), CTP4 settles down after a six-hour sedimentation step. This leads to a medium removal efficiency of 80%, allowing a significant decrease of biomass dewatering costs. Using a two-stage system, a 3-fold increase in lipid content (up to 33% of DW) and a 2-fold enhancement in lipid productivity (up to 52.1 mg L-1 d(-1)) were observed upon exposure to nutrient depletion for 7 days. The biodiesel synthesized from the lipids of CTP4 contained high levels of oleic acid (25.67% of total fatty acids content) and minor amounts of polyunsaturated fatty acids with >= 4 double bonds (< 1%). As a result, this biofuel complies with most of the European (EN14214) and American (ASTM D6751) specifications, which commonly used microalgal feedstocks are usually unable to meet. In conclusion, Tetraselmis sp. CTP4 displays promising features as feedstock with lower downstream processing costs for biomass dewatering and biodiesel refining.
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  89. Kinetics of Transesterification of Chlorella Protothecoides Microalgal Oil to Biodiesel
    Abstract

    Kumar, M.; Sharma, M. P. 2016. Kinetics of Transesterification of Chlorella Protothecoides Microalgal Oil to Biodiesel. Waste and Biomass Valorization. 7(5) 1123-1130

    Biodiesel has been receiving extensive attention in recent years due to its potential as a biodegradable and nontoxic substitute to petroleum diesel. Biodiesel derived from edible, non-edible oil and animal fat cannot satisfy even a small fraction of the existing demands due to low oil content (25-40 %) and slow growth rates (1-2 years) of oil producing plants. Microalgae is considered globally as the most promising third generation feedstocks for biodiesel production, as it requires less time for maturity (24 h-2 days) with oil productivities almost 30 times or more than the terrestrial oil seed crops. Out of various microalgae species, Chlorella protothecoides is selected as the potential feedstocks due to having high oil content (58 %), faster growth rate (24 h) and high biomass productivities (1214 mg/l/day). The present paper covers the optimization of process variables for methyl ester production using Chlorella protothecoides microalgal oil purchased from M/s Soley Institute, Turkey. The kinetics studied yielded the activation energy and reaction rate constant with maximum methyl ester yield. The results indicated that the maximum methyl ester yield of 98 % has been achieved at optimum condition of catalyst conc. of 0.5 % (w/v), methanol to oil molar ratio of 8:1, temperature of 60 A degrees C and reaction time of 60 min. The kinetics study reported that the transesterification reaction is of first order with the reaction rate of 0.034 min(-1). The stability and Cold flow property are found very good compared to other biodiesels and would not need any quantity enhancement. This kinetics result may be useful for the design and development of reactors.
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  90. Levelized cost of energy and financial evaluation for biobutanol, algal biodiesel and biohydrogen during commercial development
    Abstract

    Lee, D. H. 2016. Levelized cost of energy and financial evaluation for biobutanol, algal biodiesel and biohydrogen during commercial development. International Journal of Hydrogen Energy. 41(46) 21583-21599

    This study applies engineering economic analysis with modifications that concern profit rate, opportunity cost, price inflation, financial leverage, risk premium, learning curve effect, the effect of nth-generation chemical plants effect, interest rate and full commercializatioguren to capture realistic conditions to evaluate the economic feasibility of biohydrogen, biobutanol and algal biodiesel plants in a future bioeconomy.
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  91. Lipase-catalyzed methanolysis of microalgae oil for biodiesel production and PUFAs concentration
    Abstract

    Tian, X. G.; Dai, L. M.; Liu, M. S.; Liu, D. H.; Du, W.; Wu, H. 2016. Lipase-catalyzed methanolysis of microalgae oil for biodiesel production and PUFAs concentration. Catalysis Communications. 8444-47

    A novel process with the combined use of lipase NS81006 and Novozym435 was developed for the conversion of microalgae oils for biodiesel production and PUFAs concentration. It was found that during the first-step reaction catalyzed by NS81006, the reaction rates of PUFAs were much slower compared to those with carbon length varying from C14 to C18, but significant increase for PUFAs' conversion was achieved with Novozym435 as the catalyst for the second step conversion. A fatty acid methyl ester (FAME) yield of 95% could be obtained with this two-step enzymatic catalysis. This process has great prospect for converting microalgae oils for biodiesel preparation and PUFAs concentration. (C) 2016 Elsevier B.V. All rights reserved.
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  92. Marine microalgal culturing in open pond systems for biodiesel production-Critical parameters
    Abstract

    Sreekumar, N.; Nandagopal, M. S. G.; Vasudevan, A.; Antony, R.; Selvaraju, N. 2016. Marine microalgal culturing in open pond systems for biodiesel production-Critical parameters. Journal of Renewable and Sustainable Energy. 8(2)

    In the present scenario, petroleum sourced fuel consumption is unsustainable; therefore, there is a high demand for the development of renewable transport fuels for environmental and economic sustainability. Microalgal fuel, with the significant feature of being carbon neutral, serves as one of the potent tools for tackling the fuel crisis. Enormous researches have been explored using fresh water species on biodiesel production; nevertheless, marine species are still in a grey area, even though reported to have higher lipid content. The current review focuses on a wide spectrum of marine microalgal sources with phycology under the criteria of open pond systems for algal oil production. The discussion on the lipid expression in the marine species have been critically analysed through the vital parameters such as solar irradiation, temperature, pH, nutrient pressure, agitation, CO2 supply, culture depth, aeration, etc. The parameters are interdependent and, if scrutinized wisely, could result in enhanced lipid productivity. Therefore, the open pond culture of marine microalgae with top prioritized parameters such as nitrogen stress, pH, and light penetration will be a suitable combination for the efficient and effective biodiesel production. (C) 2016 AIP Publishing LLC.
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  93. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production
    Abstract

    Qin, L.; Wang, Z.; Sun, Y.; Shu, Q.; Feng, P.; Zhu, L.; Xu, J.; Yuan, Z. 2016. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production. Environ Sci Pollut Res Int. 23(9) 8379-87

    The potential of microalgae consortia used in dairy wastewater treatment combined with microalgae biodiesel feedstock production was evaluated by comparing the nutrient removal of dairy wastewater, the growth of cells, and the lipid content and composition of biomass between monoalgae and microalgae consortia cultivation system. Our results showed that higher chemical oxygen demand (COD) removal (maximum, 57.01-62.86 %) and total phosphorus (TP) removal (maximum, 91.16-95.96 %) were achieved in almost microalgae consortia cultivation system than those in Chlorella sp. monoalgae cultivation system (maximum, 44.76 and 86.74 %, respectively). In addition, microalgae consortia cultivation except the mixture of Chlorella sp. and Scenedesmus spp. reached higher biomass concentration (5.11-5.41 g L(-1)), biomass productivity (730.4-773.2 mg L(-1) day(-1)), and lipid productivity (143.7-150.6 mg L(-1) day(-1)) than those of monoalgae cultivation (4.72 g L(-1), 674.3, and 142.2 mg L(-1) day(-1), respectively) on the seventh day. Furthermore, the fatty acid methyl ester (FAME) profiles indicated the lipids produced from microalgae consortia cultivation system were more suitable for biodiesel production. The microalgae consortia display superiority in dairy wastewater treatment and the getting feedstock for biodiesel production.
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  94. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production
    Abstract

    Qin, L.; Wang, Z. M.; Sun, Y. M.; Shu, Q.; Feng, P. Z.; Zhu, L. D.; Xu, J.; Yuan, Z. H. 2016. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production. Environmental Science and Pollution Research. 23(9) 8379-8387

    The potential of microalgae consortia used in dairy wastewater treatment combined with microalgae biodiesel feedstock production was evaluated by comparing the nutrient removal of dairy wastewater, the growth of cells, and the lipid content and composition of biomass between monoalgae and microalgae consortia cultivation system. Our results showed that higher chemical oxygen demand (COD) removal (maximum, 57.01-62.86 %) and total phosphorus (TP) removal (maximum, 91.16-95.96 %) were achieved in almost microalgae consortia cultivation system than those in Chlorella sp. monoalgae cultivation system (maximum, 44.76 and 86.74 %, respectively). In addition, microalgae consortia cultivation except the mixture of Chlorella sp. and Scenedesmus spp. reached higher biomass concentration (5.11-5.41 g L-1), biomass productivity (730.4-773.2 mg L-1 day(-1)), and lipid productivity (143.7-150.6 mg L-1 day(-1)) than those of monoalgae cultivation (4.72 g L-1, 674.3, and 142.2 mg L-1 day(-1), respectively) on the seventh day. Furthermore, the fatty acid methyl ester (FAME) profiles indicated the lipids produced from microalgae consortia cultivation system were more suitable for biodiesel production. The microalgae consortia display superiority in dairy wastewater treatment and the getting feedstock for biodiesel production.
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  95. Microalgae from domestic wastewater facilitys high rate algal pond: Lipids extraction, characterization and biodiesel production
    Abstract

    Drira, N.; Piras, A.; Rosa, A.; Porcedda, S.; Dhaouadia, H. 2016. Microalgae from domestic wastewater facilitys high rate algal pond: Lipids extraction, characterization and biodiesel production. Bioresource Technology. 206239-244

    In this study, the harvesting of a biomass from a high rate algal pond (HRAP) of a real-scale domestic wastewater treatment facility and its potential as a biomaterial for the production of biodiesel were investigated. Increasing the medium pH to 12 induced high flocculation efficiency of up to 96% of the biomass through both sweep flocculation and charge neutralization. Lipids extracted by ultrasounds from this biomass contained around 70% of fatty acids, with palmitic and stearic acids being the most abundant. The extract obtained by supercritical CO2 contained 86% of fatty acids. Both conventional solvents extracts contained only around 10% of unsaturated fats, whereas supercritical CO2 extract contained more than 40% of unsaturated fatty acids. This same biomass was also subject to direct extractive-transesterification in a microwave reactor to produce fatty acid methyl ester, also known as, raw biodiesel.
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  96. Microalgae from the Selenastraceae as emerging candidates for biodiesel production: a mini review
    Abstract

    Yee, W. 2016. Microalgae from the Selenastraceae as emerging candidates for biodiesel production: a mini review. World Journal of Microbiology & Biotechnology. 32(4)

    Over the years, microalgae have been identified to be a potential source of commercially important products such as pigments, polysaccharides, polyunsaturated fatty acids and in particular, biofuels. Current demands for sustainable fuel sources and bioproducts has led to an extensive search for promising strains of microalgae for large scale cultivation. Prospective strains identified for these purposes were among others, mainly from the genera Hematococcus, Dunaliella, Botryococcus, Chlorella, Scenedesmus and Nannochloropsis. Recently, microalgae from the Selenastraceae emerged as potential candidates for biodiesel production. Strains from the Selenastraceae such as Monoraphidium sp. FXY-10, M. contortum SAG 47.80, Ankistrodesmus sp. SP2-15 and M. minutum were high biomass and lipid producers when cultivated under optimal conditions. A number of Selenastraceae strains were also reported to be suitable for cultivation in wastewater. This review highlights recent reports on potential strains from the Selenastraceae for biodiesel production and contrasts their biomass productivity, lipid productivity as well as fatty acid profile. Cultivation strategies employed to enhance their biomass and lipid productivity as well as to reduce feedstock cost are also discussed in this paper.
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  97. Microalgal biomass production as a sustainable feedstock for biodiesel: Current status and perspectives
    Abstract

    Abomohra, A. E.; Jin, W. B.; Tu, R. J.; Han, S. F.; Eid, M.; Eladel, H. 2016. Microalgal biomass production as a sustainable feedstock for biodiesel: Current status and perspectives. Renewable & Sustainable Energy Reviews. 64596-606

    Nowadays, fossil fuels; including coal, oil, and natural gas; are the world's primary energy sources required for industry, lighting, transportation and heating. Their needs increased dramatically due to the vast expansion in human population and economy. In contrast, a greenhouse gas emission is a serious problem arose from such uses that might lead to potentially catastrophic changes in the earth's climate. In addition, fossil fuels are limited non-renewable resources that will run out in few decades. These factors motivated many researchers to develop a new renewable energy sources that could replace fossil fuels. Biodiesel is considered as the best candidate for this purpose. Recently, microalgae were discussed as a promising feedstock for biodiesel production. This review presents a critical overview of engineered challenges compilations related to microalgal biomass production. In addition, advantages, and current limitations of biodiesel production, quantitative and qualitative feasibility of microalgal biodiesel, and its economic feasibility are discussed. (C) 2016 Elsevier Ltd. All rights reserved.
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  98. Microwave Thermolysis and Lipid Recovery from Dried Microalgae Powder for Biodiesel Production
    Abstract

    Ali, M.; Watson, I. A. 2016. Microwave Thermolysis and Lipid Recovery from Dried Microalgae Powder for Biodiesel Production. Energy Technology. 4(2) 319-330

    Third-generation microalgae-derived biodiesel has become increasingly important in recent years because of the depletion of fossil fuels and to reduce global dependence on oil from crop sources that may use or displace agricultural land for food crops. This work investigates the microwave treatment of dried microalgae powder to improve the oil extraction efficacy. This study has revealed that the lipid yield from Nannochloropsis oculata dried powder with microwave thermal treatment at 50% microwave power (443 W) was greater than that with 100% power (943 W). However, the efficacy of the cell wall destruction after 5 min microwave thermal treatment at full power was higher (70.0 +/- 2.30%) than that at 50% power (46.0 +/- 2.05%). The greatest lipid yield at 943 W was achieved with 1 min treatment, 0.093 +/- 0.001 gg(-1) of dry algae weight, with 17.3 +/- 1.19% cell lysis at 42.2 degrees C. Initially, the lipid content yield increased from 0.082 +/- 0.002 to 0.093 +/- 0.001 gg(-1) dry algae weight compared to the control sample (with no treatment applied). With the increase in temperature, the lipid yield was reduced because of oxidation at elevated temperatures. With the reduced power setting (443 W), the highest lipid yield of 0.149 +/- 0.003 gg(-1) of dry algae weight was achieved after 5 min of treatment, with 46.0 +/- 2.05% cell lysis at 58.5 degrees C. Statistically, the treatment time and temperature are correlated strongly to the extracted lipid yield. The kinetic study showed that the rate constant for lipid extraction with microwave pre-treatment was higher at 443 W compared to the control sample and the higher microwave power level. The extracted lipid was analysed and found to have physical and chemical properties that were comparable to those of vegetable seed oils and they were suitable for use as a feedstock to produce biodiesel.
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  99. Mixotrophic cultivation of microalgae using industrial flue gases for biodiesel production
    Abstract

    Kandimalla, P.; Desi, S.; Vurimindi, H. 2016. Mixotrophic cultivation of microalgae using industrial flue gases for biodiesel production. Environmental Science and Pollution Research. 23(10) 9345-9354

    In the present study, an attempt has been made to grow microalgae Scenedesmus quadricauda, Chlorella vulgaris and Botryococcus braunii in mixotropic cultivation mode using two different substrates, i.e. sewage and glucose as organic carbon sources along with flue gas inputs as inorganic carbon source. The experiments were carried out in 500 ml flasks with sewage and glucose-enriched media along with flue gas inputs. The composition of the flue gas was 7 % CO2, 210 ppm of NO (x) and 120 ppm of SOx . The results showed that S. quadricauda grown in glucose-enriched medium yielded higher biomass, lipid and fatty acid methyl esters (FAME) (biodiesel) yields of 2.6, 0.63 and 0.3 g/L, respectively. Whereas with sewage, the biomass, lipid and FAME yields of S. quadricauda were 1.9, 0.46, and 0.21 g/L, respectively. The other two species showed closer results as well. The glucose utilization was measured in terms of Chemical Oxygen Demand (COD) reduction, which was up to 93.75 % by S. quadricauda in the glucose-flue gas medium. In the sewage-flue gas medium, the COD removal was achieved up to 92 % by S. quadricauda. The other nutrients and pollutants from the sewage were removed up to 75 % on an average by the same. Concerning the flue gas treatment studies, S. quadricauda could remove CO2 up to 85 % from the flue gas when grown in glucose medium and 81 % when grown in sewage. The SOx and NOx concentrations were reduced up to 50 and 62 %, respectively, by S. quadricauda in glucose-flue gas medium. Whereas, in the sewage-flue gas medium, the SOx and NOx concentrations were reduced up to 45 and 50 %, respectively, by the same. The other two species were equally efficient however with little less significant yields and removal percentages. This study laid emphasis on comparing the feasibility in utilization of readily available carbon sources like glucose and inexpensive leftover carbon sources like sewage by microalgae to generate energy coupled with economical remediation of waste. Therefore on an industrial scale, the sewage is more preferable. Because the results obtained in the laboratory demonstrated both sewage and glucose-enriched nutrient medium are equally efficient for algae cultivation with just a slight difference. Essentially, the sewage is cost effective and easily available in large quantities compared to glucose.
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  100. Model-based optimisation of biodiesel production from microalgae
    Abstract

    Sen Gupta, S.; Shastri, Y.; Bhartiya, S. 2016. Model-based optimisation of biodiesel production from microalgae. Computers & Chemical Engineering. 89222-249

    This work presents a superstructure-based optimisation model to optimise the microalgae to biodiesel production flowsheet for the minimum net annualised life cycle cost (ALCC) of biodiesel. The model includes the important processing steps of converting microalgae into biodiesel, viz. microalgae growth, harvesting, lipid extraction, and transesterification of lipid. Different options to perform these steps are considered. The mass and volumetric balance for each process and equipment, and the equipment capacity limitations constitute the important model constraints. The decision variables include growth duration, medium, as well as the techniques and specifications to be followed in each of the downstream steps. The mixed integer linear programming model was applied to a case study of producing 30,000 kg/d biodiesel from Chlorella. The minimum ALCC was US $ 13.286/1 for the flowsheet and equipment details recommended by the model. Sensitivity analysis showed that lipid extraction was the most crucial step in the flowsheet. (C) 2016 Elsevier Ltd. All rights reserved.
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  101. NMR techniques for determination of lipid content in microalgal biomass and their use in monitoring the cultivation with biodiesel potential
    Abstract

    Sarpal, A. S.; Teixeira, C. M.; Silva, P. R.; da Costa Monteiro, T. V.; da Silva, J. I.; da Cunha, V. S.; Daroda, R. J. 2016. NMR techniques for determination of lipid content in microalgal biomass and their use in monitoring the cultivation with biodiesel potential. Appl Microbiol Biotechnol. 100(5) 2471-85

    In the present investigation, the application of NMR spectroscopic techniques was extensively used with an objective to explore the biodiesel potential of biomass cultivated on a lab scale using strains of Chlorella vulgaris and Scenedesmus ecornis. The effect of variation in the composition of culturing medium on the neutral and polar lipids productivity, and fatty acid profile of solvent extracts of microalgae biomass was studied. Determination of unsaturated fatty acid composition (C18:N = 1-3, omega3 C20:5, omega3 C22:6), polyunsaturated fatty esters (PUFEs), saturated fatty acids (SFAs), unsaturated fatty acids (UFAs), free fatty acids (FFAs), and iodine value were achieved from a single (1)H NMR spectral analysis. The results were validated by (13)C NMR and GC-MS analyses. It was demonstrated that newly developed methods based on (1)H and (13)C NMR techniques are direct, rapid, and convenient for monitoring the microalgae cultivation process for enhancement of lipid productivity and their quality aspects in the solvent extracts of microalgal biomasses without any sample treatment and prior separation compared to other methods. The fatty acid composition of algae extracts was found to be similar to vegetable and fish oils, mostly rich in C16:0, C18:N (N = 0 to 3), and n-3 omega polyunsaturated fatty acids (PUFAs). The lipid content, particularly neutral lipids, as well as most of the quality parameters were found to be medium specific by both the strains. The newly developed methods based on NMR and ultrasonic procedure developed for efficient extraction of neutral lipids are cost economic and can be an effective aid for rapid screening of algae strains for modulation of lipid productivity with desired biodiesel quality and value-added products including fatty acid profile.
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  102. NMR techniques for determination of lipid content in microalgal biomass and their use in monitoring the cultivation with biodiesel potential
    Abstract

    Sarpal, A. S.; Teixeira, C. M. L. L.; Silva, P. R. M.; Monteiro, T. V. D.; da Silva, J. I.; da Cunha, V. S.; Daroda, R. J. 2016. NMR techniques for determination of lipid content in microalgal biomass and their use in monitoring the cultivation with biodiesel potential. Applied Microbiology and Biotechnology. 100(5) 2471-2485

    In the present investigation, the application of NMR spectroscopic techniques was extensively used with an objective to explore the biodiesel potential of biomass cultivated on a lab scale using strains of Chlorella vulgaris and Scenedesmus ecornis. The effect of variation in the composition of culturing medium on the neutral and polar lipids productivity, and fatty acid profile of solvent extracts of microalgae biomass was studied. Determination of unsaturated fatty acid composition (C18: N = 1-3,.3 C20: 5,.3 C22: 6), polyunsaturated fatty esters (PUFEs), saturated fatty acids (SFAs), unsaturated fatty acids (UFAs), free fatty acids (FFAs), and iodine value were achieved from a single H-1 NMR spectral analysis. The results were validated by C-13 NMR and GC-MS analyses. It was demonstrated that newly developed methods based on 1H and 13C NMR techniques are direct, rapid, and convenient for monitoring the microalgae cultivation process for enhancement of lipid productivity and their quality aspects in the solvent extracts of microalgal biomasses without any sample treatment and prior separation compared to other methods. The fatty acid composition of algae extracts was found to be similar to vegetable and fish oils, mostly rich in C16: 0, C18: N (N = 0 to 3), and n-3 omega polyunsaturated fatty acids (PUFAs). The lipid content, particularly neutral lipids, as well as most of the quality parameters were found to be medium specific by both the strains. The newly developed methods based on NMR and ultrasonic procedure developed for efficient extraction of neutral lipids are cost economic and can be an effective aid for rapid screening of algae strains for modulation of lipid productivity with desired biodiesel quality and value-added products including fatty acid profile.
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  103. Opportunities for simultaneous oil extraction and transesterification during biodiesel fuel production from microalgae: A review
    Abstract

    Skorupskaite, V.; Makareviciene, V.; Gumbyte, M. 2016. Opportunities for simultaneous oil extraction and transesterification during biodiesel fuel production from microalgae: A review. Fuel Processing Technology. 15078-87

    The biodiesel industry has undergone stable growth over the past decade. The biodiesel production process is relatively complex and rather expensive relative to the production of mineral diesel, and thus to retain production shares and expand the industry, there is a growing demand for changes related to the search for new raw materials and advanced technologies. Microalgae have attracted considerable attention as a potential biodiesel raw material. This article presents an overview of possible applications of one new form of technology, the so-called in situ technology for simultaneous oil extraction and transesterification. The article also describes ways of applying this technological tool for biodiesel production from microalgae oil. (C) 52016 Elsevier B.V. All rights reserved.
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  104. Optimal Integration of Algae-Switchgrass Facility for the Production of Methanol and Biodiesel
    Abstract

    Martin, M.; Grossmann, I. E. 2016. Optimal Integration of Algae-Switchgrass Facility for the Production of Methanol and Biodiesel. Acs Sustainable Chemistry & Engineering. 4(10) 5651-5658

    In this work we integrate switchgrass and algae in order to operate a biorefinery with no need for fossil based raw materials in the production of biodiesel (FAME). A superstructure optimization approach is used to select the optimal integrated topology, gasification, and reforming technologies, that provide the thermal energy and the methanol that biodiesel production requires. The excess of methanol can be sold as biofuel or it can be further processed to gasoline. The optimal integrated process involves indirect gasification followed by steam reforming based on the need for a high H-2 to CO ratio to produce methanol and to avoid the use of oxygen. The integrated process produces 776 ML/year (205 Mgal/year) of biofuels, 34% FAME, at 0.14 (sic)/L (0.53 (sic)/gal). The plant does not emit CO2, but captures 1.27 kg of CO2 per kg of methanol produced.
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  105. Optimization of algal lipid extraction by mixture of ethyl acetate and ethanol via response surface methodology for biodiesel production
    Abstract

    Lu, W. D.; Alam, M. A.; Pan, Y.; Nock, W. J.; Wang, Z. M.; Yuan, Z. H. 2016. Optimization of algal lipid extraction by mixture of ethyl acetate and ethanol via response surface methodology for biodiesel production. Korean Journal of Chemical Engineering. 33(9) 2575-2581

    The effects of extraction time, extraction temperature, solvent to biomass ratio and solvent composition on lipid yield from lyophilized Chlorococcum sp. biomass using a mixture of ethyl acetate and ethanol (EAE), a new proposed solvent, were studied. Subsequently, the process conditions of extraction by EAE were optimized using Box-Behnken design (BBD). The results revealed that the extraction temperature had the greatest effect on lipid extraction efficiency, followed by volume ratio of ethyl acetate to ethanol (EA/E) and extraction time. The largest lipid extraction yield of 15.74% was obtained under the following extraction conditions: 40mL solvents per gram of biomass for 270 min with gentle stirring at 80 A degrees C by EAE with an EA/E of 1.0. Furthermore, palmitic acid, stearic acid, oleic acid, and linoleic acid were the most abundant fatty acids in the lipids extracted, indicating the great potential of the proposed lipid extraction procedure for microalgae-based biodiesel production.
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  106. Production of biodiesel from freshwater microalgae and evaluation of fuel properties based on fatty acid methyl ester profile
    Abstract

    Sinha, S. K.; Gupta, A.; Bharalee, R. 2016. Production of biodiesel from freshwater microalgae and evaluation of fuel properties based on fatty acid methyl ester profile. Biofuels-Uk. 7(1) 69-78

    Eleven freshwater microalgal strains of Chlorella sorokiniana BTA4015; Chlorella sp. BTA4032, C. variabilis BTA4036; Chlorella sp. BTA4071; C. variabilis BTA4109; C. variabilis BTA4121; Chlorella sp. BTA4146; Chlamydomonas asymmetrica BTA4028; C. asymmetrica BTA4154; Scenedesmus armatus BTA4076 and Scenedesmus regularis BTA4112 were isolated from northeast India and identified through internal transcribed spacer 2 region sequence alignment. Algal strains cultured in 20 L carboys in outdoor condition in tap water enriched with NPK showed doubling time ranged between 1.5-6.8 d, lipid content (4.5 - 9.1% dry wt), biomass productivity (6 -26 mg L (1) d (1)) and lipid productivity (0.31 - 1.99 mg L (1) d (1)). The biodiesel properties of iodine value, saponification value, cetane number, high heating value, oxidation stability, allylic and bis-allylic position equivalent, kinematic viscosity, cold filter plugging point, cloud point, pour point and C18: 3 were calculated from fatty acid profile. Equally weighted parameters for biodiesel component using Preference Ranking Organization Method for Enrichment Evaluation and Graphical Analysis for Interactive Assistance analysis ranked Chlorella variabilis BTA4109 & BTA4036, C. sorokiniana BTA4015 the most suitable strains meeting the EN14214 biodiesel standard. The biomass productivity for the three strains recorded 20.83, 26.04 and 6.83 mg L (1) d (1) whereas the lipid productivity recorded 0.95, 1.89 and 0.32 mg L (1) d (1) respectively.
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  107. Production of biodiesel from freshwater microalgae and evaluation of fuel properties based on fatty acid methyl ester profile (vol 7, pg 69, 2016)
    Abstract

    Sinha, S. K.; Gupta, A.; Bharalee, R. 2016. Production of biodiesel from freshwater microalgae and evaluation of fuel properties based on fatty acid methyl ester profile (vol 7, pg 69, 2016). Biofuels-Uk. 7(1) E-E

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  108. Production of bio-oil from algal biomass and its upgradation to biodiesel using CaO-based heterogeneous catalysts
    Abstract

    Malpani, M.; Varma, A. K.; Mondal, P. 2016. Production of bio-oil from algal biomass and its upgradation to biodiesel using CaO-based heterogeneous catalysts. International Journal of Green Energy. 13(10) 969-976

    The present article deals with the production of bio-oil from algal biomass as well as the preparation and characterization of noble CaO-based heterogeneous catalyst for upgradation of bio-oil to biodiesel. The bio-oil has been extracted from algal biomass using hexane as solvent in soxhlet apparatus and upgraded to biodiesel by transesterification using noble CaO-based heterogeneous catalysts. Catalyst with TiO2:CaO molar ratio of 0.25 and calcination temperature of 700 degrees C has been found to be most suitable among all the catalysts developed. Characterization of the catalysts has been done by using X-ray diffraction (XRD), scanning electron microscope (SEM), and thermo-gravimetric analysis (TGA). The input--output model has been developed to correlate experimental and predicted value of biodiesel yield. Optimization of process parameters has been done using response surface methodology. Various properties and elemental composition of algal bio-oil and biodiesel have been determined and compared with biodiesel.
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  109. Progress and Challenges in Microalgal Biodiesel Production
    Abstract

    Mallick, N.; Bagchi, S. K.; Koley, S.; Singh, A. K. 2016. Progress and Challenges in Microalgal Biodiesel Production. Frontiers in Microbiology. 7

    The last decade has witnessed a tremendous impetus on biofuel research due to the irreversible diminution of fossil fuel reserves for enormous demands of transportation vis-a-vis escalating emissions of green house gasses (GHGs) into the atmosphere. With an imperative need of CO2 reduction and considering the declining status of crude oil, governments in various countries have not only diverted substantial funds for biofuel projects but also have introduced incentives to vendors that produce biofuels. Currently, biodiesel production from microalgal biomass has drawn an immense importance with the potential to exclude high -quality agricultural land use and food safe-keeping issues. Moreover, microalgae can grow in seawater or wastewater and microalgal oil can exceed 50-60% (dry cell weight) as compared with some best agricultural oil crops of only 5-10% oil content. Globally, microalgae are the highest biomass producers and neutral lipid accumulators contending any other terrestrial oil crops. However, there remain many hurdles in each and every step, starting from strain selection and lipid accumulation/yield, algae mass cultivation followed by the downstream processes such as harvesting, drying, oil extraction, and biodiesel conversion (transesterification), and overall, the cost of production. Isolation and screening of oleaginous microalgae is one pivotal important upstream factor which should be addressed according to the need of freshwater or marine algae with a consideration that wild-type indigenous isolate can be the best suited for the laboratory to large scale exploitation. Nowadays, a large number of literature on microalgal biodiesel production are available, but none of those illustrate a detailed step-wise description with the pros and cons of the upstream and downstream processes of biodiesel production from microalgae. Specifically, harvesting and drying constitute more than 50% of the total production costs; however, there are quite a less number of detailed study reports available. In this review, a pragmatic and critical analysis was tried to put forward with the on-going researches on isolation and screening of oleaginous microalgae, microalgal large scale cultivation, biomass harvesting, drying, lipid extraction and finally biodiesel production.
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  110. Progress on lipid extraction from wet algal biomass for biodiesel production
    Abstract

    Ghasemi Naghdi, F.; Gonzalez Gonzalez, L. M.; Chan, W.; Schenk, P. M. 2016. Progress on lipid extraction from wet algal biomass for biodiesel production. Microb Biotechnol. 9(6) 718-726

    Lipid recovery and purification from microalgal cells continues to be a significant bottleneck in biodiesel production due to high costs involved and a high energy demand. Therefore, there is a considerable necessity to develop an extraction method which meets the essential requirements of being safe, cost-effective, robust, efficient, selective, environmentally friendly, feasible for large-scale production and free of product contamination. The use of wet concentrated algal biomass as a feedstock for oil extraction is especially desirable as it would avoid the requirement for further concentration and/or drying. This would save considerable costs and circumvent at least two lengthy processes during algae-based oil production. This article provides an overview on recent progress that has been made on the extraction of lipids from wet algal biomass. The biggest contributing factors appear to be the composition of algal cell walls, pre-treatments of biomass and the use of solvents (e.g. a solvent mixture or solvent-free lipid extraction). We compare recently developed wet extraction processes for oleaginous microalgae and make recommendations towards future research to improve lipid extraction from wet algal biomass.
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  111. Progress on lipid extraction from wet algal biomass for biodiesel production
    Abstract

    Naghdi, F. G.; Gonzalez, L. M. G.; Chan, W.; Schenk, P. M. 2016. Progress on lipid extraction from wet algal biomass for biodiesel production. Microbial Biotechnology. 9(6) 718-726

    Lipid recovery and purification from microalgal cells continues to be a significant bottleneck in biodiesel production due to high costs involved and a high energy demand. Therefore, there is a considerable necessity to develop an extraction method which meets the essential requirements of being safe, cost-effective, robust, efficient, selective, environmentally friendly, feasible for large-scale production and free of product contamination. The use of wet concentrated algal biomass as a feedstock for oil extraction is especially desirable as it would avoid the requirement for further concentration and/or drying. This would save considerable costs and circumvent at least two lengthy processes during algae-based oil production. This article provides an overview on recent progress that has been made on the extraction of lipids from wet algal biomass. The biggest contributing factors appear to be the composition of algal cell walls, pre-treatments of biomass and the use of solvents (e.g. a solvent mixture or solvent-free lipid extraction). We compare recently developed wet extraction processes for oleaginous microalgae and make recommendations towards future research to improve lipid extraction from wet algal biomass.
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  112. Recycled de-Oiled Algal Biomass Extract as a Feedstock for Boosting Biodiesel Production from Chlorella minutissima
    Abstract

    Arora, N.; Patel, A.; Pruthi, P. A.; Pruthi, V. 2016. Recycled de-Oiled Algal Biomass Extract as a Feedstock for Boosting Biodiesel Production from Chlorella minutissima. Applied Biochemistry and Biotechnology. 180(8) 1534-1541

    The investigation for the first time assesses the efficacy of recycled de-oiled algal biomass extract (DABE) as a cultivation media to boost lipid productivity in Chlorella minutissima and its comparison with Bold's basal media (BBM) used as control. Presence of organic carbon (3.8 +/- A 0.8 g/l) in recycled DABE resulted in rapid growth with twofold increase in biomass productivity as compared to BBM. These cells expressed four folds higher lipid productivity (126 +/- A 5.54 mg/l/d) as compared to BBM. Cells cultivated in recycled DABE showed large sized lipid droplets accumulating 54.12 % of lipid content. Decrement in carbohydrate (17.76 %) and protein content (28.12 %) with loss of photosynthetic pigments compared to BBM grown cells were also recorded. The fatty acid profiles of cells cultivated in recycled DABE revealed the dominance of C16:0 (39.66 %), C18:1 (29.41 %) and C18:0 (15.82 %), respectively. This model is self-sustained and aims at neutralizing excessive feedstock consumption by exploiting recycled de-oiled algal biomass for cultivation of microalgae, making the process cost effective.
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  113. Screening fatty acid composition of British heterotrophic microalgae thraustochytrids for production of omega-3 oils and biodiesel
    Abstract

    Marchan, L. F. 2016. Screening fatty acid composition of British heterotrophic microalgae thraustochytrids for production of omega-3 oils and biodiesel. New Biotechnology. 33S91-S91

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  114. Screening of freshwater and seawater microalgae strains in fully controlled photobioreactors for biodiesel production
    Abstract

    Taleb, A.; Kandilian, R.; Touchard, R.; Montalescot, V.; Rinaldi, T.; Taha, S.; Takache, H.; Marchal, L.; Legrand, J.; Pruvost, J. 2016. Screening of freshwater and seawater microalgae strains in fully controlled photobioreactors for biodiesel production. Bioresource Technology. 218480-490

    Strain selection is one of the primary hurdles facing cost-effective microalgal biodiesel production. Indeed, the strain used affects both upstream and downstream biodiesel production processes. This study presents a screening procedure that considers the most significant criteria in microalgal biodiesel production including TAG production and wet extraction and recovery of TAGs. Fourteen freshwater and seawater strains were investigated. Large variation was observed between the strains in all the screening criteria. The overall screening procedure ultimately led to the identification of Parachlorella kessleri UTEX2229 and Nannochloropsis gaditana CCMP527 as the best freshwater and seawater strains, respectively. They featured the largest areal TAG productivity equal to 2.7 x 10(-3) and 2.3 x 10(-3) kg m(-2) d(-1), respectively. These two strains also displayed encouraging cell fragility in a high pressure bead milling process with 69% and 98% cell disruption at 1750 bar making them remarkable strains for TAG extraction in wet environment. (C) 2016 Elsevier Ltd. All rights reserved.
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  115. Site Selection for Large-Scale Algae Cultivation towards Biodiesel Production
    Abstract

    Tachoth, V.; Rose, A. 2016. Site Selection for Large-Scale Algae Cultivation towards Biodiesel Production. International Journal of Renewable Energy Research. 6(4) 1416-1422

    Fuel deficiency is one of the severe threats confronted by the whole world. This foreshadows about a situation where the resources would be insufficient to meet the energy requirements of industries, automobiles, and household equipments. Biofuels have been attracting the scientific world with its properties similar to that of fossil fuels and the capability to get renewed. Alga is widely studied owing to its high lipid content and potential to produce larger quantity of oil than other crops. When compared to food crops and other raw materials, alga is the best feedstock for biodiesel. The requisites for algae cultivation can be met easily which are fewer than that for food crops. But some hurdles are inhibiting the high productivity of algae and profitable algae farming. Lack of suitable sites is the major sticking point that hauls the production of biodiesel to the lowest. This article discusses the survey conducted for the selection of sites pertinent for large-scale algae growth aiming at a high yield of biodiesel. Maps of surveyed locations and charts showing the importance of algae cultivation have been included. The manuscript elaborates the geographical features of each location and shows their aptness to be selected as algae farming sites. Comparison of oil yield from different crops has been shown through graphs. Information regarding algae, similarity of biodiesel to petroleum products, implementation of algae as the feedstock for biodiesel, different processing techniques available for biodiesel production via extraction of oil from algae etc is also comprised in the article.
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  116. Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock
    Abstract

    Zhu, L. D.; Li, Z. H.; Hiltunen, E. 2016. Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock. Biomed Research International.

    In response to the energy crisis, global warming, and climate changes, microalgae have received a great deal of attention as a biofuel feedstock. Due to a high lipid content in microalgal cells, microalgae present as a promising alternative source for the production of biodiesel. Environmental and culturing condition variations can alter lipid production as well as chemical compositions of microalgae. Therefore, application of the strategies to activate lipid accumulation opens the door for lipid overproduction in microalgae. Until now, many original studies regarding the approaches for enhanced microalgal lipid production have been reported in an effort to push forward the production of microalgal biodiesel. However, the current literature demonstrates fragmented information available regarding the strategies for lipid production improvement. From the systematic point of view, the review highlights the main approaches for microalgal lipid accumulation induction to expedite the application of microalgal biodiesel as an alternative to fossil diesel for sustainable environment. Of the several strategies discussed, the one that is most commonly applied is the design of nutrient (e.g., nitrogen, phosphorus, and sulfur) starvation or limitation. Other viable approaches such as light intensity, temperature, carbon dioxide, salinity stress, and metal influence can also achieve enhanced microalgal lipid production.
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  117. Study on the harvest of oleaginous microalgae Chlorella sp by photosynthetic hydrogen mediated auto-flotation for biodiesel production
    Abstract

    Feng, Q. Z.; Chen, M.; Wang, W. R.; Chang, S.; Zhang, L.; Li, J. H.; Li, S. Z. 2016. Study on the harvest of oleaginous microalgae Chlorella sp by photosynthetic hydrogen mediated auto-flotation for biodiesel production. International Journal of Hydrogen Energy. 41(38) 16772-16777

    Harvesting of microalgae biomass is recognized as the bottleneck of algal-based biodiesel production due to its high cost and energy input. In this study, an original harvesting system, the co-flotation using the H-2 producing filamentous cyanobacterium Anabaena sp. PCC7120 to concentrate the oleaginous alga Chlorella sp., was presented as an alternative strategy. Different mixing ratios of Anabaena and Chlorella were investigated, and 1: 1 (v/v) was shown to be optimal. In the optimal system, each 100 hydrogen producing cells could float 669 Chlorella cells. The lipid of the floating cells was extracted and analyzed. by GC-MS. Results suggested that the co-floated algal cells were rich in saturated fatty acids, higher than Chlorella alone, and thus ideal for biodiesel production. Scale up to 1 L experiments demonstrated the system to have the potential for commercial production. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
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  118. Supercritical carbon dioxide treatment of the microalgae Nannochloropsis oculata for the production of fatty acid methyl esters
    Abstract

    McKennedy, J.; Onenc, S.; Pala, M.; Maguire, J. 2016. Supercritical carbon dioxide treatment of the microalgae Nannochloropsis oculata for the production of fatty acid methyl esters. Journal of Supercritical Fluids. 116264-270

    The aim of this work was to evaluate the potential of supercritical carbon dioxide (CO2) to extract fatty acid methyl esters (FAME) from the microalgae Nannochloropsis oculata (N. oculata) at low temperatures (37 and 55 degrees C) and pressures (5.9 and 7.6 megapascals (MPa)). A qualitative gas chromatography (GC) analysis showed that the individual FAMEs extracted varied depending on the co-solvent (methanol or hexane) used with supercritical CO2. Using hexane, FAME compounds produced were similar to those extracted with soxhlet extraction alone while longer chain FAME were produced when methanol was the co-solvent. The effects of pressure and temperature variations were shown to be of statistical significance. The chromatograms produced in this work demonstrate that altering one of these parameters (co-solvent, temperature, pressure) can produce different compounds owing to the tunability of the technique. (C) 2016 Elsevier B.V. All rights reserved.
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  119. Sustainable production of biodiesel from microalgae by direct transesterification
    Abstract

    Lemoes, J. S.; Sobrinho, R. C. M. A.; Farias, S. P.; de Moura, R. R.; Primel, E. G.; Abreu, P. C.; Martins, A. F.; D'Oca, M. G. M. 2016. Sustainable production of biodiesel from microalgae by direct transesterification. Sustainable Chemistry and Pharmacy. 333-38

    This study addresses the question of the sustainable production of biodiesel (fatty acid ethyl esters) by direct transesterification from Chlorella sp. The lipid fractions from Chlorella sp. using chloroform: methanol, methanol, and ethanol were obtained and the acid value measurements were 39.4, 58.2, and 82.5 mg KOH/g, respectively. Following this, transesterification of algal lipid extraction and direct transesterification was undertaken in the presence of ethanol and the results were compared with those for methanol. Apart from the lower yield in extracted lipids obtained with ethanol, when ethanol was used for transesterification of the algal lipid extraction, surprisingly, similar yields of fatty acid ethyl esters and fatty acid methyl esters were obtained. Furthermore, direct transesterification from Chlorella sp. provided higher ethyl and methyl esters yields than was the case with the extraction-transesterification process. Ethanol, a renewable feedstock, is the most sustainable alternative, which, compared to methanol in direct transesterification, resulted in similar fatty acid methyl and ethyl ester yields (11.6% and 11.0%, respectively, in the same experimental conditions). (C) 2016 Elsevier B.V. All rights reserved.
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  120. Techno-economics of Algal Biodiesel
    Abstract

    Louw, T. M.; Griffiths, M. J.; Jones, S. M. J.; Harrison, S. T. L. 2016. Techno-economics of Algal Biodiesel. Algae Biotechnology: Products and Processes. 111-141

    Algal biodiesel production presents a possible carbon-neutral source of transportation fuel. Whilst algal biodiesel circumvents some of the issues arising from the use of crop-and waste-biomass-based fuels, the lack of commercial success raises questions regarding the feasibility of the process. Numerous economic and environmental impact assessments have produced highly variable results, predicting costs from as little as 0.42-72 USD L-1. A meta-analysis of these assessments reveals that areal productivity and provision of nutrients, as well as energy and water usage, are the key challenges to algal biodiesel production. A consideration of maximum achievable photosynthetic activity indicates that some scope exists for increasing areal productivity; hence, the factors influencing productivity are discussed in detail. Carbon dioxide supply may represent the single most important challenge to algal biodiesel, while recycling of other nutrients (specifically nitrogen and phosphate) is essential. Finally, a careful balance must be struck between energy and water consumption; this balance is primarily influenced by bioreactor design. It is unlikely that algal biodiesel will supply a substantial portion of the world's transportation energy demand, but it may fill niche markets such as aviation fuel. Process economics are enhanced by integrating biodiesel production into a biorefinery, producing a suite of products.
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  121. Third generation biodiesel production from microalgae Phormidium autumnale
    Abstract

    Siqueira, S. F.; Francisco, E. C.; Queiroz, M. I.; de Menezes, C. R.; Zepka, L. Q.; Jacob-Lopes, E. 2016. Third generation biodiesel production from microalgae Phormidium autumnale. Brazilian Journal of Chemical Engineering. 33(3) 427-433

    The aim of this work was to evaluate third generation biodiesel production by the microalgae Phormidium autumnale using sucrose as exogenous carbon source. The study focused on optimization of the different C/N ratios and on the analysis of biofuel quality. The results indicate that a C/N ratio of 40 improved the performance of the system, reaching single-cell oil productivities of 18.9 mg/L in steady-state conditions. This oil has a composition predominantly saturated (45.2%) and monounsaturated (34.7%) suitable for biodiesel synthesis (ester content of 99.8%, cetane number of 58.5%, iodine value of 67.2 gI(2)/100 g, unsaturation degree of 71.3% and a cold filter plugging point of 6.7 degrees C).
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  122. Transesterification of oil extracted from freshwater algae for biodiesel production
    Abstract

    Fatima, N.; Mahmood, M. S.; Hussain, I.; Siddique, F.; Hafeez, S. 2016. Transesterification of oil extracted from freshwater algae for biodiesel production. Energy Sources Part a-Recovery Utilization and Environmental Effects. 38(15) 2306-2311

    Currently, energy crisis is a burning issue throughout the world, particularly in underdeveloped countries like Pakistan where the demand of conventional fuels has been increasing day by day. The main objective of this project was the production of biodiesel from Algae. Samples of freshwater were collected. The Chlorella species produced 6.26 g oil from 38.23 g of dry weight and the Oedogonium species produced 8.07 g of oil from 38.23 g of dried weight. The biomass obtained after oil extraction was 31.97 g from chlorella species and 30.16 g from Oedogonium species. The fatty acids that were displayed by a gas chromatographic machine in chlorella species were capric acid, nanoic acid, arachidonic acid, behenic acid, and erucic acid and in oedogonium species they were capric acid, butyric acid, behenic acid, luric acid, tridecanoic acid, and arachidonic acid.
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  123. Water Footprint of Biodiesel Production from Microalgae Cultivated in Photobioreactors
    Abstract

    Feng, P. Z.; Zhu, L. D.; Qin, X. X.; Li, Z. H. 2016. Water Footprint of Biodiesel Production from Microalgae Cultivated in Photobioreactors. Journal of Environmental Engineering. 142(12)

    Based on experimental data, this study determined the water footprint of biodiesel production from freshwater microalgae cultivated in photobioreactors. The findings highlighted the necessity of recycling harvest water and applying undiluted wastewater to grow microalgae in efforts to save freshwater resources. Without water recycling, approximately 3,494kg freshwater was required to produce 1kg microalgal biodiesel. By contrast, recycling harvest water at the degree of 50 and 100% to regrow microalgae could reduce the water utilization by 39.4 and 93.0%, respectively. The results also showed that using undiluted wastewater to grow microalgae could decrease the usage of freshwater by 93.7%, reaching as low as 219kgwater/kilogram microalgal biodiesel produced. Factors that affect the water footprint of microalgal biodiesel production were also discussed in this study. (C) 2016 American Society of Civil Engineers.
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  124. A Cost Analysis of Microalgal Biomass and Biodiesel Production in Open Raceways Treating Municipal Wastewater and under Optimum Light Wavelength
    Abstract

    Kang, Z.; Kim, B. H.; Ramanan, R.; Choi, J. E.; Yang, J. W.; Oh, H. M.; Kim, H. S. 2015. A Cost Analysis of Microalgal Biomass and Biodiesel Production in Open Raceways Treating Municipal Wastewater and under Optimum Light Wavelength. Journal of Microbiology and Biotechnology. 25(1) 109-118

    Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the effect of using wastewater and wavelength filters on microalgal productivity. Experimental results were then fitted into a model, and cost analysis was performed in comparison with control raceways. Three different microalgal strains, Chlorella vulgaris AG10032, Chlorella sp. JK2, and Scenedesmus sp. JK10, were tested for nutrient removal under different light wavelengths (blue, green, red, and white) using filters in batch cultivation. Blue wavelength showed an average of 27% higher nutrient removal and at least 42% higher chemical oxygen demand removal compared with white light. Naturally, the specific growth rate of microalgae cultivated under blue wavelength was on average 10.8% higher than white wavelength. Similarly, lipid productivity was highest in blue wavelength, at least 46.8% higher than white wavelength, whereas FAME composition revealed a mild increase in oleic and palmitic acid levels. Cost analysis reveals that raceways treating wastewater and using monochromatic wavelength would decrease costs from 2.71 to 0.73 $/kg biomass. We prove that increasing both biomass and lipid productivity is possible through cost-effective approaches, thereby accelerating the commercialization of low-value products from microalgae, like biodiesel.
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  125. A novel recovery process for lipids from microalgae for biodiesel production using a hydrated phosphonium ionic liquid
    Abstract

    Olkiewicz, M.; Caporgno, M. P.; Font, J.; Legrand, J.; Lepine, O.; Plechkova, N. V.; Pruvost, J.; Seddon, K. R.; Bengoa, C. 2015. A novel recovery process for lipids from microalgae for biodiesel production using a hydrated phosphonium ionic liquid. Green Chemistry. 17(5) 2813-2824

    The use of a hydrated phosphonium ionic liquid, [P(CH2OH)(4)]Cl, for the extraction of microalgae lipids for biodiesel production, was evaluated using two microalgae species, Chlorella vulgaris and Nannochloropsis oculata. The ionic liquid extraction was compared to the conventional Soxhlet, and Bligh & Dyer, methods, giving the highest extraction efficiency in the case of C. vulgaris, at 8.1%. The extraction from N. oculata achieved the highest lipid yield for Bligh & Dyer (17.3%), while the ionic liquid extracted 12.8%. Nevertheless, the ionic liquid extraction showed high affinity to neutral/saponifiable lipids, resulting in the highest fatty acid methyl esters (FAMEs)-biodiesel yield (4.5%) for C. vulgaris. For N. oculata, the FAMEs yield of the ionic liquid and Bligh & Dyer extraction methods were similar (>8%), and much higher than for Soxhlet (<5%). The ionic liquid extraction proved especially suitable for lipid extraction from wet biomass, giving even higher extraction yields than from dry biomass, 14.9% and 12.8%, respectively (N. oculata). Remarkably, the overall yield of FAMEs was almost unchanged, 8.1% and 8.0%, for dry and wet biomass. The ionic liquid extraction process was also studied at ambient temperature, varying the extraction time, giving 75% of lipid and 93% of FAMEs recovery after thirty minutes, as compared to the extraction at 100 degrees C for one day. The recyclability study demonstrated that the ionic liquid was unchanged after treatment, and was successfully reused. The ionic liquid used is best described as [P(CH2OH)(4)]Cl center dot 2H(2)O, where the water is not free, but strongly bound to the ions.
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  126. A review on the extraction of lipid from microalgae for biodiesel production
    Abstract

    Mubarak, M.; Shaija, A.; Suchithra, T. V. 2015. A review on the extraction of lipid from microalgae for biodiesel production. Algal Research-Biomass Biofuels and Bioproducts. 7117-123

    Biofuels produced from algal biomass are the most suitable alternative fuels for the future, as microalgae biomass can accumulate lipids within their cell similar to vegetable oils with a potential to produce 100 times more oil per acrel and than any other plants. The methods used for the extraction of lipid from microalgae are either mechanical or chemical method. The chemical methods of lipid extraction are Soxhlet extraction, supercritical fluid extraction, accelerated solvent extraction and mechanical methods are oil expeller, microwave assisted extraction, ultrasonic assisted extraction. This paper is a review of different methods used for extracting oils or lipids from microalgae biomass for biodiesel production. It is seen that lipid extraction yield from microalgae could be increased by using pretreatment methods such as ultrasonication and microwave-assisted techniques along with solvent extraction. (C) 2014 Elsevier B.V. All rights reserved.
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  127. Algal biomass and biodiesel production by utilizing the nutrients dissolved in seawater using semi-permeable membrane photobioreactors
    Abstract

    Kim, Z. H.; Park, H.; Ryu, Y. J.; Shin, D. W.; Hong, S. J.; Tran, H. L.; Lim, S. M.; Lee, C. G. 2015. Algal biomass and biodiesel production by utilizing the nutrients dissolved in seawater using semi-permeable membrane photobioreactors. Journal of Applied Phycology. 27(5) 1763-1773

    The objective of this study is developing microalgal culture systems to produce biodiesel with low-energy inputs in the ocean. The semi-permeable membrane photobioreactors (SPM-PBRs), which are capable of transferring nutrients dissolved in seawater into the algal broth while containing the cells inside, were operated in a reservoir containing Incheon coastal seawater in the laboratory to observe biomass dynamics, variations in nutrient concentration, pH, and salinity prior to their deployment in the ocean. A green microalga Tetraselmis sp., isolated from Incheon nearshore, was cultivated in a simulated ocean condition under continuous illumination. According to the data obtained from the experiment, microalgal growth was found to be primarily limited by the phosphorus concentration in seawater rather than other major nutrients (carbon and nitrogen) and the pH and salinity of the algal broth, which remained constant. Furthermore, we were able to understand why biomass productivity decreases as the culture progresses. N and P transfer rates through the membranes gradually decreased due to membrane fouling caused by various factors. For an enhancement of nutrient transfer rate and biomass productivity, various SPMs with different nutrient transfer rates and molecular weight cut-offs (MWCOs) were also explored. Biomass productivity increased in proportion to the nutrient transfer rate of the membranes, and the fatty acid content increased from 12 to 30 % at day 0 without a significant change in its composition. With further developments in SPM-PBRs, another technology to simultaneously produce microalgal biomass and reverse eutrophication of the ocean or lakes may be provided.
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  128. An alternative method for production of microalgal biodiesel using novel Bacillus lipase
    Abstract

    Surendhiran, D.; Sirajunnisa, A. R.; Vijay, M. 2015. An alternative method for production of microalgal biodiesel using novel Bacillus lipase. 3 Biotech. 5(5) 715-725

    In this study, enzymatic interesterification is carried out using encapsulated lipase as biocatalyst with methyl acetate as acyl acceptor in a solvent-free system. Lipase, isolated from a marine bacterial isolate, Bacillus sp.S23 (KF220659.1) was immobilized in sodium alginate beads. This investigation elaborated on the effects of various parameters, namely enzyme loading, temperature, water, molar ratio, reaction time and agitation for interesterification. The study resulted in the following optimal conditions: 1.5 g immobilized lipase, 1:12 molar ratio of oil to methyl acetate, 35 degrees C, 8 % water, 60 h reaction time, 250 rpm of agitation. With the standardized condition, the maximum conversion efficiency was 95.68 %. The immobilized beads, even after ten cycles of repeated usage showed high stability in the presence of methyl acetate and no loss of lipase activity. The microalgal biodiesel composition was analyzed using gas chromatography. The current study was efficient in using immobilized lipase for the interesterification process, since the method was cost-effective and eco-friendly, no solvent was involved and the enzyme was encapsulated in a natural polymer.
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  129. Anaerobic Digestion as a Tool for Resource Recovery from a Biodiesel Production Process from Microalgae
    Abstract

    Torres, A.; Fermoso, F. G.; Neumann, P.; Azocar, L.; Nunez, D. J. 2015. Anaerobic Digestion as a Tool for Resource Recovery from a Biodiesel Production Process from Microalgae. Journal of Biobased Materials and Bioenergy. 9(3) 342-349

    Microalgae are considered a promising feedstock of biomass for the production of biofuels. The capacity of some strains to accumulate lipids makes them an interesting alternative for biodiesel production. The anaerobic digestion of the spent (lipid-extracted) biomass has been proposed as a way to increase energy yield and sustainability of bioenergy production from microalgae. Anaerobic digestion would produce biogas, but also would provide conditions for nutrients recovery. Present research was oriented to determine potential contribution of anaerobic digestion of spent biomass to biodiesel production from microalgae. Two rnicroalgae species were considered in this study, Botryococcus braunii and Nannochloropsis gaditana. Bio-methane potential tests revealed methane yields of 407 and 450 mL CH4/gVS for B. braunii and N. gaditana, respectively. Latter values represent 56 and 61% of total energy in spent microalgae, measured as calorific potential. Mass and energy balances for biodiesel and biogas production indicate that close to 14% of the energy contained in the biomass could be transferred to biodiesel. When biogas is also produced, potential energetic yield of both biofuels would increases to close to 55%. Energy balances of a potential biodiesel and biogas production indicate that traditional harvesting methods such as centrifugation and the inclusion of a biomass drying step process would yield negative energetic balances, even when biogas and biodiesel are both produced. Thus, future research efforts should focus on the development of low energy harvesting methods and in alternatives for biomass processing circumventing biomass drying.
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  130. Analysis of some chemical elements in marine microalgae for biodiesel production and other uses
    Abstract

    Silva, B. F.; Wendt, E. V.; Castro, J. C.; de Oliveira, A. E.; Carrim, A. J. I.; Vieira, J. D. G.; Sassi, R.; Sassi, C. F. D.; da Silva, A. L. V.; BarbozaD, G. F. D.; Antoniosi, N. R. 2015. Analysis of some chemical elements in marine microalgae for biodiesel production and other uses. Algal Research-Biomass Biofuels and Bioproducts. 9312-321

    Due to the currently abundant supply of marine microalgae, which can be found in seawater, as well as microalgae's ability to uptake different chemicals, it appears as a promising raw material with potential for many commercial uses. Despite having a high amount of metal in their biomass, the lipids within marine microalgae can be converted into biodiesel. Analyses of 26 chemical elements (Al, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, P, Pb, Sn, Sr, Ti, Tl, V, and Zn) were performed by ICP-OES with the goal of quantifying the inorganic content of marine microalgae's biomass. Regardless of the cultivation media used, microalgae presented differences in their chemical element profile. Strains showed a 12.9% to 36.3% mass of analyzed elements per dry biomass, which represent a relatively high percentage for a feedstock used in biofuels. Among the 36 assayed microalgae, Biddulphia sp., Planktolyngbya limnetica, Amphora sp. (1), Navicula sp. (3) and Synechococcus sp. are most indicated for this purpose as they contain a lower concentration of chemical elements when compared to other samples. However, their profile warns that water quality control is needed for toxic metals such as Ba, Cd, and Pb. (C) 2015 Elsevier B.V. All rights reserved.
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  131. Biochemical Modulation of Lipid Pathway in Microalgae Dunaliella sp for Biodiesel Production
    Abstract

    Talebi, A. F.; Tohidfar, M.; Derazmahalleh, S. M. M.; Sulaiman, A.; Baharuddin, A. S.; Tabatabaei, M. 2015. Biochemical Modulation of Lipid Pathway in Microalgae Dunaliella sp for Biodiesel Production. Biomed Research International.

    Exploitation of renewable sources of energy such as algal biodiesel could turn energy supplies problem around. Studies on a locally isolated strain of Dunaliella sp. showed that the mean lipid content in cultures enriched by 200 mg L-1 myoinositol was raised by around 33% (1.5 times higher than the control). Similarly, higher lipid productivity values were achieved in cultures treated by 100 and 200 mg L-1 myoinositol. Fluorometry analyses (microplate fluorescence and flow cytometry) revealed increased oil accumulation in the Nile red-stained algal samples. Moreover, it was predicted that biodiesel produced from myoinositol-treated cells possessed improved oxidative stability, cetane number, and cloud point values. From the genomic point of view, real-time analyses revealed that myoinositol negatively influenced transcript abundance of AccD gene (one of the key genes involved in lipid production pathway) due to feedback inhibition and that its positive effect must have been exerted through other genes. The findings of the current research are not to interprete that myoinositol supplementation could answer all the challenges faced in microalgal biodiesel production but instead to show that "there is a there there" for biochemical modulation strategies, which we achieved, increased algal oil quantity and enhanced resultant biodiesel quality.
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  132. Biodiesel from wastewater: lipid production in high rate algal pond receiving disinfected effluent
    Abstract

    Assemany, P. P.; Calijuri, M. L.; do Couto, E. D. A.; Santiago, A. F.; dos Reis, A. J. D. 2015. Biodiesel from wastewater: lipid production in high rate algal pond receiving disinfected effluent. Water Science and Technology. 71(8) 1229-1234

    The production of different species of microalgae in consortium with other micro-organisms from wastewaters may represent an alternative process, to reduce the costs, for obtaining biofuels. The aim of this study was to evaluate the influence of pre-ultraviolet disinfection (UV) in the production of lipids from biomass produced in high rate ponds. Two high rate algal ponds were evaluated: a pond that received domestic sewage without disinfection and the other receiving domestic sewage previously disinfected by UV radiation (uvHRAP). The UV disinfection did not lead to significant differences in fatty acid profile and total lipid productivities, although it increased algal biomass concentration and productivity as well as lipid content. Moreover, the overall biomass concentrations and productivities decreased with the UV disinfection, mostly as a consequence of a loss in bacterial load. We thus conclude that uvHRAP disinfection may represent a potential strategy to promote the cleaner and safer growth of algal biomass when cultivated in consortium with other microorganisms. Mainly regarding the use of wastewater as culture medium, together with a cheaper production of lipids for biodiesel, pre-disinfection may represent an advance since extraction costs could be significantly trimmed due to the increase in lipid content.
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  133. Biodiesel Fuel Production from Microalgae Oil by Applying Enzymatic Transesterification with Ethanol
    Abstract

    Makareviciene, V.; Gumbyte, M.; Skorupskaite, V.; Navasinskaite, M. 2015. Biodiesel Fuel Production from Microalgae Oil by Applying Enzymatic Transesterification with Ethanol. 7th International Scientific Conference Rural Development 2015: Towards the Transfer of Knowledge, Innovations and Social Progress.

    Rapeseed is currently the main raw material for biodiesel production in Europe. The search for new raw materials is very important for the increase of biodiesel fuel production volume. Microalgae are one of alternatives for biodiesel fuel production. In this research, transesterification of microalgae Chlorella sp. oil with ethanol by applying the biotechnological method has been studied. The effectiveness of seven commercial lipases was evaluated. The most effective lipase Lipolase 100 L was selected for optimization of reaction conditions. The influence of main process parameters, including the ethanol to oil molar ratio, lipase amount and process duration on transesterification yield was evaluated. The results revealed, that process duration and amount of lipase affected the transesterification yield mostly. The biodiesel yield higher than 96.5 % could be obtained when ethanol and oil molar ratio in reaction mixture is 8:1, process duration - 24 hours, lipase amount - 8 %.
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  134. Biodiesel production by direct transesterification of microalgal biomass with co-solvent
    Abstract

    Zhang, Y.; Li, Y.; Zhang, X.; Tan, T. W. 2015. Biodiesel production by direct transesterification of microalgal biomass with co-solvent. Bioresource Technology. 196712-715

    In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce the energy consumption of lipid extraction process and improve the conversion yield of the microalgae biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to 75% ethanol volume ratio 1: 2, mixed solvent dosage 6.0 mL, reaction temperature 90 degrees C, reaction time 2.0 h and catalyst volume 0.6 mL, the direct transesterification process of microalgal biomass resulted in a high conversion yield up to 90.02 +/- 0.55 wt.%. (C) 2015 Elsevier Ltd. All rights reserved.
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  135. Biodiesel Production from Green Microalgae Schizochytrium limacinum via in Situ Transesterification
    Abstract

    Bi, Z. T.; He, B. B.; McDonald, A. G. 2015. Biodiesel Production from Green Microalgae Schizochytrium limacinum via in Situ Transesterification. Energy & Fuels. 29(8) 5018-5027

    Microalgae are considered as one of the most promising feedstocks for biofuel production because of their environmental and social benefits. However, challenges exist in converting microalgal lipids into algal biofuels because of the unique characteristics of microalgae and the technologies for processing them. This study aims at exploring an alternative sub-/supercritical methanol (subCM/SCM) process technology that combines lipid extraction from whole microalgae and lipid esterification/transesterification in a single step or in situ transesterification. A high lipid content microalgal strain, Schizochytrium limacinum, was used for in situ transesterification in a batch reactor. Temperature (170, 210, 250, and 290 degrees C), reaction time (30, 60, 90, and 120 min), and lipid/methanol molar ratio (sRatio; 1:50, 1:75, and 1:100) were investigated for their effects on the conversion efficiency. The temperature appeared as a most positive influential factor. Additionally, the operating temperature over 250 degrees C caused degradation of the lipids and/or algal biomass and, thus, led to the decline of the ester yield. The combination of the reaction time and temperature had a significant impact on the in situ transesterification reaction. The sRatio had a statistically significant impact on the product yield and purity, and both these two response factors reached the maximum levels after the sRatio reached 1:75. It was observed that the highest product purity (37.5 wt %) occurred at sRatio of 1:75, 211.6 degrees C, and 120 min, with a product yield of 58.4 mol %. This study shows that the in situ transesterification of microalgae bears some advantages over the traditional two-step processes and has the potential to be applied to large-scale processing for biodiesel production.
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  136. Biodiesel production from microalgae oil catalyzed by a recombinant lipase
    Abstract

    Huang, J. J.; Xia, J.; Jiang, W.; Li, Y.; Li, J. L. 2015. Biodiesel production from microalgae oil catalyzed by a recombinant lipase. Bioresource Technology. 18047-53

    A recombinant Rhizomucor miehei lipase was constructed and expressed in Pichia pastoris. The target enzyme was termed Lipase GH2 and it can be used as a free enzyme for catalytic conversion of microalgae oil mixed with methanol or ethanol for biodiesel production in an n-hexane solvent system. Conversion rates of two major types of biodiesel, fatty acid methyl ester (FAME) and fatty acid ethyl ester (FAEE), reached maximal values (>90%) after 24 h. The process of FAME production is generally more simple and economical than that of FAEE production, even though the two processes show similar conversion rates. In spite of the damaging effect of ethanol on enzyme activity, we successfully obtained ethyl ester by the enzymatic method. Our findings indicate that Lipase GH2 is a useful catalyst for conversion of microalgae oil to FAME or FAEE, and this system provides efficiency and reduced costs in biodiesel production. (C) 2014 Elsevier Ltd. All rights reserved.
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  137. Biodiesel Production From the Microalgae Nannochloropsis by Microwave Using CaO and MgO Catalysts
    Abstract

    Hindarso, H.; Aylianawati; Sianto, M. E. 2015. Biodiesel Production From the Microalgae Nannochloropsis by Microwave Using CaO and MgO Catalysts. International Journal of Renewable Energy Development-Ijred. 4(1) 72-76

    The needs of world petroleum are increased; in contrast, the fuel productions are getting decreased. Therefore, it has lead to the search for bio-fuel as an alternative energy. There are several different types of biofuel, such as biodiesel, ethanol, bioalcohol, and biogas. Biodiesel is typically made by chemically reacting lipids from a vegetable oil or animal fat with an alcohol producing fatty acid esters, such as methyl or ethyl ester. The present study aimed to study the effect of temperature (50, 60 and 65 degrees C), reaction time (1 to 5 minutes) dan types of catalyst (CaO dan MgO of 1 and 3 %) in the production of biodiesel from microalgae by the transesterification process using microwave methods. It also studied the characteristics of biodiesel which had the greatest yield in the present study, i.e. flash point, cetane number, density, viscosity, and FAME. The greatest yield was 99.35% and obtained with combination of 3% MgO catalyst quantity at temperature of 60 degrees C, in 3 minutes reaction time. At this process conditions, the biodiesel has a flash point of 122 degrees C, cetane number of 55, density of 0.89, viscosity of 5 cP and FAME of 75.12 %.
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  138. Biodiesel Production from Wet Marine Microalgae via a One-step Direct Process in the Presence of an Adsorbent
    Abstract

    Kwon, M. H.; Yeom, S. H. 2015. Biodiesel Production from Wet Marine Microalgae via a One-step Direct Process in the Presence of an Adsorbent. Biotechnology and Bioprocess Engineering. 20(3) 593-598

    To decrease the cost of biodiesel production from microalgae, biodiesel was produced from wet marine microalgae by a one-step direct process. In this process, simultaneous lipid extraction from the wet microalgae and transesterification of the lipid with methanol was conducted. Among the combinations of catalysts and organic extraction solvents that were evaluated, sulfuric acid and chloroform represented the optimum combination. The degree of water content for wet microalgae significantly influenced biodiesel production: in the presence of 348.4% water content in intact wet microalgae, lipid extraction efficiency (LEE) was 73.2% and biodiesel conversion (BC) was 50.5%, but at a lower water content of 185.7%, LEE increased to 84.7% and BC to 69.9%. Increasing the amount of chloroform by 50% relative to the standard amount increased LEE and BC to 81.2 and 56.1%, respectively. Of the adsorbents evaluated, zeolite noticeably increased LEE to 98.7%. Increasing the amount of chloroform by 50% in the presence of zeolite caused a further significant increase in LEE and BC to 98.3 and 75.3%, respectively. These results indicated that biodiesel production from wet microalgae could be enhanced markedly by the addition of adsorbents with increased amounts of organic extraction solvents.
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  139. Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes
    Abstract

    Chen, C. L.; Huang, C. C.; Ho, K. C.; Hsiao, P. X.; Wu, M. S.; Chang, J. S. 2015. Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes. Bioresource Technology. 194179-186

    Although producing biodiesel from microalgae seems promising, there is still a lack of technology for the quick and cost-effective conversion of biodiesel from wet microalgae. This study was aimed to develop a novel microalgal biodiesel producing method, consisting of an open system of microwave disruption, partial dewatering (via combination of methanol treatment and low-speed centrifugation), oil extraction, and transesterification without the pre-removal of the co-solvent, using Chlamydomonas sp. JSC4 with 68.7 wt% water content as the feedstock. Direct transesterification with the disrupted wet microalgae was also conducted. The biomass content of the wet microalgae increased to 56.6 and 60.5 wt%, respectively, after microwave disruption and partial dewatering. About 96.2% oil recovery was achieved under the conditions of: extraction temperature, 45 degrees C; hexane/methanol ratio, 3: 1; extraction time, 80 min. Transesterification of the extracted oil reached 97.2% conversion within 15 min at 45 degrees C and 6: 1 solvent/methanol ratio with simultaneous Chlorophyll removal during the process. Nearly 100% biodiesel conversion was also obtained while conducting direct transesterification of the disrupted oil-bearing microalgal biomass. (C) 2015 Elsevier Ltd. All rights reserved.
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  140. Biodiesel production from wet microalgal biomass by direct transesterification
    Abstract

    Macias-Sanchez, M. D.; Robles-Medina, A.; Hita-Pena, E.; Jimenez-Callejon, M. J.; Esteban-Cerdan, L.; Gonzalez-Moreno, P. A.; Molina-Grima, E. 2015. Biodiesel production from wet microalgal biomass by direct transesterification. Fuel. 15014-20

    The aim of this work was to optimize the production of fatty acid methyl esters (FAMEs, biodiesel) from marine Nannochloropsis gaditana wet microalgal biomass (25 wt% dry biomass and 11.1 wt% saponifiable lipids, SLs, of dry biomass) by direct acid catalyzed methylation of SLs in the microagal biomass and extraction of FAMEs with hexane. The best FAME yield was attainted with a methanol/SL ratio of 171.1 mL/g, an acetyl chloride (catalyst) concentration of 5% (v/v), 100 degrees C and a reaction time of 105 min. In these conditions 100% of SLs were transformed to FAMEs. Similar yields were obtained at lower temperatures and higher reaction times. The pretreatment of wet biomass by homogenization did not improve the above results. Finally, the FAME purity was increased from 74.5 to 82.7 wt% by a treatment of adsorption with bentonite. (C) 2015 Elsevier Ltd. All rights reserved.
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  141. Biodiesel production process from microalgae oil by waste heat recovery and process integration
    Abstract

    Song, C. F.; Chen, G. Y.; Ji, N.; Liu, Q. L.; Kansha, Y.; Tsutsumi, A. 2015. Biodiesel production process from microalgae oil by waste heat recovery and process integration. Bioresource Technology. 193192-199

    In this work, the optimization of microalgae oil (MO) based biodiesel production process is carried out by waste heat recovery and process integration. The exergy analysis of each heat exchanger presented an efficient heat coupling between hot and cold streams, thus minimizing the total exergy destruction. Simulation results showed that the unit production cost of optimized process is 0.592 $/L biodiesel, and approximately 0.172 $/L biodiesel can be avoided by heat integration. Although the capital cost of the optimized biodiesel production process increased 32.5 % and 23.5 % compared to the reference cases, the operational cost can be reduced by approximately 22.5 % and 41.6 %. (C) 2015 Elsevier Ltd. All rights reserved.
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  142. Biodiesel yields and fuel quality as criteria for algal-feedstock selection: Effects of CO2-supplementation and nutrient levels in cultures
    Abstract

    Nascimento, I. A.; Cabanelas, I. T. D.; dos Santos, J. N.; Nascimento, M. A.; Sousa, L.; Sansone, G. 2015. Biodiesel yields and fuel quality as criteria for algal-feedstock selection: Effects of CO2-supplementation and nutrient levels in cultures. Algal Research-Biomass Biofuels and Bioproducts. 853-60

    Microalgae-oil yields and quality, associated with CO2-fixation rates, are able to enhance the feasibility of algal-biodiesel production and economics. Those issues were used as selective criteria applied to Trebouxiophyceae strains. Chlorella vulgaris and two Botryococcus strains were confirmed to grow and to produce high quality biodiesels at distinct levels (2.5 to 20%) of CO2-supplementation. Nevertheless, under nutrient-sufficient conditions, C. vulgaris showed the highest CO2-fixation rate (0.611 g L-1 d(-1)) and biomass production at 5% CO2-supplementation, while for Botryococcus terribilis and Botryococcus braunii, the maximum rates (0.614 and 0.555 g L-1 d(-1) CO2) were obtained at 10%-supplementation. Under nutrient-deficient conditions lipids have increased to be above the contents found during the exponential growth-phase, by a maximum of 43%. The fatty-acid profiles varied according to strains and CO2-levels in cultures. Despite variation, palmitic, oleic and linoleic acids predominated. The higher percentage of oleic and palmitic acids over stearic acid, tended to balance the excess of the long chain-size and saturation effects on algal biodiesels' ignition and cold-flow properties. Thus, CO2-supplemented levels from 2.5 to 10.0% made biodiesels compliant with fuel-quality standards. Based on the obtained CO2-fixation rates biodiesels were projected to minimum yields of 42 to 46 L ha(-1) d(-1). (C) 2015 Elsevier B.V. All rights reserved.
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  143. Biological butanol production from microalgae-based biodiesel residues by Clostridium acetobutylicum
    Abstract

    Cheng, H. H.; Whang, L. M.; Chan, K. C.; Chung, M. C.; Wu, S. H.; Liu, C. P.; Tien, S. Y.; Chen, S. Y.; Chang, J. S.; Lee, W. J. 2015. Biological butanol production from microalgae-based biodiesel residues by Clostridium acetobutylicum. Bioresource Technology. 184379-385

    This study conducted batch experiments to evaluate the potential of butanol production from microalgae biodiesel residues by Clostridium acetobutylicum. The results indicated that with 90 g/L of glucose as the sole substrate the highest butanol yield of 0.2 g/g-glucose was found, but the addition of butyrate significantly enhanced the butanol yield. The highest butanol yield of 0.4 g/g-glucose was found with 60 g/L of glucose and 18 g/L of butyrate. Using microalgae biodiesel residues as substrate, C. acetobutylicum produced 3.86 g/L of butanol and achieved butanol yield of 0.13 g/g-carbohydrate via ABE fermentation, but the results indicated that approximately one third of carbohydrate was not utilized by C. acetobutylicum. Biological butanol production from microalgae biodiesel residues can be possible, but further research on fermentation strategies are required to improve production yield. (C) 2014 Elsevier Ltd. All rights reserved.
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  144. Bio-oil and Biodiesel as Biofuels Derived from Microalgal Oil and Their Characterization by Using Instrumental Techniques
    Abstract

    Kumar, D.; Singh, B.; Bauddh, K.; Korstad, J. 2015. Bio-oil and Biodiesel as Biofuels Derived from Microalgal Oil and Their Characterization by Using Instrumental Techniques. Algae and Environmental Sustainability. 787-95

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  145. Characterization and fatty acid profiling in two fresh water microalgae for biodiesel production: Lipid enhancement methods and media optimization using response surface methodology
    Abstract

    Karpagam, R.; Raj, K. J.; Ashokkumar, B.; Varalakshmi, P. 2015. Characterization and fatty acid profiling in two fresh water microalgae for biodiesel production: Lipid enhancement methods and media optimization using response surface methodology. Bioresource Technology. 188177-184

    Two fresh water microalgae, Coelastrella sp. M-60 and Micractinium sp. M-13 were investigated in this study for their potential of biodiesel production. For increasing biomass and lipid production, these microalgae were subjected to nutrient starvation (nitrogen, phosphorous, iron), salinity stress and nutrient supplementation with sugarcane industry effluent, citric acid, glucose and vitamin B-12. The lipid productivity obtained from the isolates Coelastrella sp. M-60 (13.9 +/- 0.4 mg/L/day) and Micractinium sp. M-13 (11.1 +/- 0.2 mg/L/day) was maximum in salinity stress. The media supplemented with all the four nutrients yielded higher lipid productivity than the control. The response surface methodology (RSM) was employed to evaluate the effect of sugarcane industry effluent and citric acid on growth and lipid yield. Fatty acid profile of Coelastrella sp. M-60 and Micractinium sp. M-13 were composed of C-14, C-16:0, C-18:0, C-18:1 and C-18:2 and their fuel properties were also in accordance with international standards. (C) 2015 Elsevier Ltd. All rights reserved.
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  146. Characterization of five fresh water microalgae with potential for biodiesel production
    Abstract

    Valdez-Ojeda, R.; Gonzalez-Munoz, M.; Us-Vazquez, R.; Narvaez-Zapata, J.; Chavarria-Hernandez, J. C.; Lopez-Adrian, S.; Barahona-Perez, F.; Toledano-Thompson, T.; Garduno-Solorzano, G.; Medrano, R. M. E. G. 2015. Characterization of five fresh water microalgae with potential for biodiesel production. Algal Research-Biomass Biofuels and Bioproducts. 733-44

    Microalgae biodiesel feedstocks have been investigated by numerous research groups to overcome dependence on fossil fuels. This study describes a detailed characterization of five freshwater microalgae strains of the family Scenedesmaceae, based on cell wall ultrastructure, ITS-2 sequence and secondary structure analysis, as well as the estimation of biodiesel properties from fatty acids produced before and after N-limitation. Characterization permitted the reclassification of SCRE-1 and SCRE-2 strains into the subgenus Scenedesmus; DSRE-1 and DSRE-2 strains into the subgenus Desmodesmus; and CORE-1 strain into the genus Coelastrum. Transesterification of fatty acids of the five strains was performed before and after N-limitation, and seven important biodiesel quality parameters were predicted by applying selected correlations. These parameters were then compared to the corresponding specifications in the American and European biodiesel standards. N-limitation promoted higher yields of biomass (up to 3.5 times) and lipids (up to 4.1 times) in all strains under study. Moreover, it was found that SCRE-2 was the only biodiesel that met all estimated parameters of the more stringent European standard before N-limitation. This was also true for DSRE-1 and DSRE-2 biodiesels after limitation, with the exception of their oxidative stability parameter, whose values met the limit of the American but not the European standard. (C) 2014 Elsevier B.V. All rights reserved.
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  147. Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae
    Abstract

    Im, H.; Kim, B.; Lee, J. W. 2015. Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae. Bioresource Technology. 193386-392

    This work addresses an unprecedented way of co-producing biodiesel (FAEE) and valuable chemicals of ethyl levulinate (EL), ethyl formate (EF) and diethyl ether (DEE) from wet in situ transesterification of microalgae. EL, EF, and DEE were significantly produced up to 23.1%, 10.3%, and 52.1% of the maximum FAEE mass with the FAEE yield higher than 90% at 125 degrees C. Experiments to elucidate a detailed route of EL and EF synthesis were fulfilled and it was found that its main route to the production of EL and EF was the acid hydrolysis of algal cells and esterification with ethanol. To investigate the effect of reaction variables on the products yields, comprehensive experiments were carried out with varying temperatures, solvent and alcohol volumes, moisture contents and catalyst amounts. Coproduction of DEE, EL, EF and FAEE can contribute to elevating the economic feasibility of microalgae-based biodiesel supply chain. (C) 2015 Elsevier Ltd. All rights reserved.
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  148. Cultivation of algae consortium in a dairy farm wastewater for biodiesel production
    Abstract

    Hena, S.; Fatimah, S.; Tabassum, S. 2015. Cultivation of algae consortium in a dairy farm wastewater for biodiesel production. Water Resources and Industry. 101-14

    Dairy farm wastewaters are potential resources for production of microalgae bioluels. A study was conducted to evaluate the capability of production of biodiesel from consortium of native microalgae culture in dairy farm treated wastewater. Native algal strains were isolated from dairy farm wastewaters collection tank (untreated wastewater) as well as from holding tank (treated wastewater). The consortium members were selected on the basis of fluorescence response after treating with Nile red reagent. Preliminary studies of two commercial and consortium of ten native strains of algae showed good growth in wastewaters. A consortium of native strains was found capable to remove more than 98% nutrients from treated wastewater. The biomass production and lipid content of consortium cultivated in treated wastewater were 153.54 t ha(-1) year(-1) and 16.89%, respectively. 72.70% of algal lipid obtained from consortium could be converted into biodiesel. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.ors/licenses/by/4.0/).
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  149. Development and validation of a screening procedure of microalgae for biodiesel production: Application to the genus of marine microalgae Nannochloropsis
    Abstract

    Taleb, A.; Pruvost, J.; Legrand, J.; Marec, H.; Le-Gouic, B.; Mirabella, B.; Legeret, B.; Bouvet, S.; Peltier, G.; Li-Beisson, Y.; Taha, S.; Takache, H. 2015. Development and validation of a screening procedure of microalgae for biodiesel production: Application to the genus of marine microalgae Nannochloropsis. Bioresource Technology. 177224-232

    Nannochloropsis has emerged as a promising alga for biodiesel production. However, the genus consists of 6 species and hundreds of strains making strain selection a challenge. Furthermore, oil productivity is instrumental to economic viability of any algal strain for industrial production, which is dependent on growth rate and oil content. In most cases, these two parameters have been studied independently. Thus, the goal of this study is to provide a combined method for evaluating strain performance in specially designed photobioreactors together with an in-depth lipidomic analyses. The nine strains of Nannochloropsis tested showed considerable variations in productivity and lipidomics highlighting the importance of strain selection. Finally, Nannochloropsis gaditana CCMP527 and Nannochloropsis salina CCMP537 emerged as the two most promising strains, with an oil content of 37 and 27 dry wt% after 11-day nitrogen starvation, respectively, resulting in TAG productivity of 13 x 10(-3) and 18 x 10(-3) kg m(-3) d(-1), respectively. (C) 2014 Elsevier Ltd. All rights reserved.
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  150. Development of direct conversion method for microalgal biodiesel production using wet biomass of Nannochloropsis salina
    Abstract

    Kim, T. H.; Suh, W. I.; Yoo, G.; Mishra, S. K.; Farooq, W.; Moon, M.; Shrivastav, A.; Park, M. S.; Yang, J. W. 2015. Development of direct conversion method for microalgal biodiesel production using wet biomass of Nannochloropsis salina. Bioresource Technology. 191438-444

    In this work, the effects of several factors, such as temperature, reaction time, and solvent and acid quantity on in situ transesterification yield of wet Nannochloropsis salina were investigated. Under equivalent total solvent volume to biomass ratio, pure alcohol showed higher yield compared to alcohol-chloroform solvent. For esterifying 200 mg of wet cells, 2 ml of methanol and 1 ml of ethanol was sufficient to complete in situ transesterification. Under temperatures of 105 degrees C or higher, 2.5% and 5% concentrations of sulfuric acid was able to successfully convert more than 90% of lipid within 30 min when methanol and ethanol was used as solvents respectively. Also, it was verified that the optimal condition found in small-scale experiments is applicable to larger scale using 2 L scale reactor as well. (C) 2015 Elsevier Ltd. All rights reserved.
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  151. Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach
    Abstract

    Dong, T.; Yu, L.; Gao, D. F.; Yu, X. C.; Miao, C.; Zheng, Y. B.; Lian, J. N.; Li, T. T.; Chen, S. L. 2015. Direct quantification of fatty acids in wet microalgal and yeast biomass via a rapid in situ fatty acid methyl ester derivatization approach. Applied Microbiology and Biotechnology. 99(23) 10237-10247

    Accurate determination of fatty acid contents is routinely required in microalgal and yeast biofuel studies. A method of rapid in situ fatty acid methyl ester (FAME) derivatization directly from wet fresh microalgal and yeast biomass was developed in this study. This method does not require prior solvent extraction or dehydration. FAMEs were prepared with a sequential alkaline hydrolysis (15 min at 85 A degrees C) and acidic esterification (15 min at 85 A degrees C) process. The resulting FAMEs were extracted into n-hexane and analyzed using gas chromatography. The effects of each processing parameter (temperature, reaction time, and water content) upon the lipids quantification in the alkaline hydrolysis step were evaluated with a full factorial design. This method could tolerate water content up to 20 % (v/v) in total reaction volume, which equaled up to 1.2 mL of water in biomass slurry (with 0.05-25 mg of fatty acid). There were no significant differences in FAME quantification (p > 0.05) between the standard AOAC 991.39 method and the proposed wet in situ FAME preparation method. This fatty acid quantification method is applicable to fresh wet biomass of a wide range of microalgae and yeast species.
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  152. Direct transesterification of wet microalgal biomass for preparation of biodiesel
    Abstract

    Suh, W. I.; Mishra, S. K.; Kim, T. H.; Farooq, W.; Moon, M.; Shrivastav, A.; Park, M. S.; Yang, J. W. 2015. Direct transesterification of wet microalgal biomass for preparation of biodiesel. Algal Research-Biomass Biofuels and Bioproducts. 12405-411

    Most conventional processes for algal biodiesel production involve separate lipid extraction steps or require usage of dry biomass that incurs extra cost and an energy intensive drying step. A novel process that involves dehydration of wet biomass via pretreatment with ethanol followed by direct in situ transesterification into biodiesel was investigated in this study. Under mild esterification at 80 degrees C for 30 min, pretreating the wet biomass twice with 3 volumes of ethanol resulted in a nearly four-fold increase of fatty acid ethyl ester (FAEE) yield from 3.04 mg to 11.78 mg, while increasing the ethanol from 1 volume to 10 volumes resulted in a six fold increase of yield from 3.18 to 18.29 mg. The FAEE yield further increased when the esterification reaction was run at higher temperature and longer durations of up to 120 degrees C for 2 h. The overall positive impact of the pretreatment step on the final yield was far greater for milder reaction conditions, which makes the process more attractive in terms of economics and energy savings. In addition, it was found that the yield is unaffected by the choice of alcohol, which means methanol and butanol can also be used for the process. Lastly, it was found that the low concentration of water in the FAEE containing spent ethanol meant that both the solvent and sulfuric acid could be reused to further concentrate the quantity of FAEE in the final product mixture. (C) 2015 Elsevier B.V. All rights reserved.
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  153. Dual uses of microalgal biomass: An integrative approach for biohydrogen and biodiesel production
    Abstract

    Dasgupta, C. N.; Suseela, M. R.; Mandotra, S. K.; Kumar, P.; Pandey, M. K.; Toppo, K.; Lone, J. A. 2015. Dual uses of microalgal biomass: An integrative approach for biohydrogen and biodiesel production. Applied Energy. 146202-208

    Dual application of biomass for biohydrogen and biodiesel production could be considered a feasible option for economic and sustainable energy production from microalgae. In this study, after a large screening of fresh water microalgal isolates, Scenedesmus sp. NBRI012 and Chlorella sp. NBRIO29 have exhibited high biomass (1.31 +/- 0.11 and 2.62 +/- 0.13 g/L respectively) and lipid (244.44 +/- 12.3 and 587.38 +/- 20.2 mg/L respectively) yield with an organic carbon (acetate) source. Scenedesmus sp. NBRI012 has shown the highest H-2 (maximum evolution of 17.72% v/v H-2 of total gases) production; it produced H-2 continuously for seven days in sulfur-deprived TAP media. Sulfur deprivation during the H-2 production was found to increase the lipid content (410.03 +/- 18.5 mg/L) of the residual biomass. Fatty acid profile of the lipid extracted from the residual biomass of Scenedesmus sp. NBRI012 has showed abundance of fatty acids with a carbon chain length of C16 and C18. Cetane number, iodine value, and saponification value of biodiesel were found suitable according to the range given by the Indian standard (IS 15607), Brazilian National Petroleum Agency (ANP255) and the European biodiesel standard EN14214. (c) 2015 Elsevier Ltd. All rights reserved.
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  154. Effects of Different Biomass Drying and Lipid Extraction Methods on Algal Lipid Yield, Fatty Acid Profile, and Biodiesel Quality
    Abstract

    Hussain, J.; Liu, Y.; Lopes, W. A.; Druzian, J. I.; Souza, C. O.; Carvalho, G. C.; Nascimento, I. A.; Liao, W. 2015. Effects of Different Biomass Drying and Lipid Extraction Methods on Algal Lipid Yield, Fatty Acid Profile, and Biodiesel Quality. Applied Biochemistry and Biotechnology. 175(6) 3048-3057

    Three lipid extraction methods of hexane Soxhlet (Sox-Hex), Halim (HIP), and Bligh and Dyer (BD) were applied on freeze-dried (FD) and oven-dried (OD) Chlorella vulgaris biomass to evaluate their effects on lipid yield, fatty acid profile, and algal biodiesel quality. Among these three methods, HIP was the preferred one for C. vulgaris lipid recovery considering both extraction efficiency and solvent toxicity. It had the highest lipid yields of 20.0 and 22.0 % on FD and OD biomass, respectively, with corresponding neutral lipid yields of 14.8 and 12.7 %. The lipid profiling analysis showed that palmitic, oleic, linoleic, and alpha-linolenic acids were the major fatty acids in the algal lipids, and there were no significant differences on the amount of these acids between different drying and extraction methods. Correlative models applied to the fatty acid profiles concluded that high contents of palmitic and oleic acids in algal lipids contributed to balancing the ratio of saturated and unsaturated fatty acids and led to a high-quality algal biodiesel.
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  155. Enzymatic Production of Biodiesel from Microalgal Oil using Ethyl Acetate as an Acyl Acceptor
    Abstract

    Alavijeh, R. S.; Tabandeh, F.; Tavakoli, O.; Karkhane, A.; Shariati, P. 2015. Enzymatic Production of Biodiesel from Microalgal Oil using Ethyl Acetate as an Acyl Acceptor. Journal of Oleo Science. 64(1) 69-74

    Microalgae have become an important source of biomass for biodiesel production. In enzymatic transesterification reaction, the enzyme activity is decreased in presence of alcohols. The use of different acyl acceptors such as methyl/ethyl acetate is suggested as an alternative and effective way to overcome this problem. In this study, ethyl acetate was used for the first time in the enzymatic production of biodiesel by using microalga, Chlorella vulgaris, as a triglyceride source. Enzymatic conversion of such fatty acids to biodiesel was catalyzed by Novozym 435 as an efficient immobilized lipase which is extensively used in biodiesel production. The best conversion yield of 66.71% was obtained at the ethyl acetate to oil molar ratio of 13:1 and Novozym 435 concentration of 40%, based on the amount of oil, and a time period of 72 h at 40 degrees C. The results showed that ethyl acetate have no adverse effect on lipase activity and the biodiesel amount was not decreased even after seven transesterification cycles, so ethyl acetate has a great potential to be substituted for short-chain alcohols in transesterification reaction.
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  156. Enzymatic Production of Biodiesel from Nannochloropsis gaditana Microalgae Using Immobilized Lipases in Mesoporous Materials
    Abstract

    Bautista, L. F.; Vicente, G.; Mendoza, A.; Gonzalez, S.; Morales, V. 2015. Enzymatic Production of Biodiesel from Nannochloropsis gaditana Microalgae Using Immobilized Lipases in Mesoporous Materials. Energy & Fuels. 29(8) 4981-4989

    A study of the production of fatty acid methyl and ethyl esters (FAMEs and FAEEs) to be used as biodiesel was carried out with Nannochloropsis gaditana oil using three fungal lipases (from Thermomyces lanuginosus, Candida antarctica B, and Mucor miehei) both free and immobilized in hexagonal (SBA-15 and MCM-41) and cubic (FDU-12 and SBA-16) mesoporous supports. The operating variables were optimized using free lipase (ethanol, 40 degrees C, 24 h, 500:1 oil/lipase mass ratio, and 8:1 ethanol/oil mass ratio). Higher FAEE yields were obtained with supported lipase than with free lipase because of the protection and stability given by the supports. The FAEE yields achieved were higher for lipase immobilized in hexagonal mesostructured materials because lipase molecules are more accessible than lipase immobilized in the three-dimensional cubic supports. C. antarctica lipase B immobilized in functionalized SBA-15 showed the better performance and reusability among the biocatalysts used.
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  157. Ferric chloride based downstream process for microalgae based biodiesel production
    Abstract

    Seo, Y. H.; Sung, M.; Kim, B.; Oh, Y. K.; Kim, D. Y.; Han, J. I. 2015. Ferric chloride based downstream process for microalgae based biodiesel production. Bioresource Technology. 181143-147

    In this study, ferric chloride (FeCl3) was used to integrate downstream processes (harvesting, lipid extraction, and esterification). At concentration of 200 mg/L and at pH 3, FeCl3 exhibited an expected degree of coagulation and an increase in cell density of ten times (170 mg/10 mL). An iron-mediated oxidation reaction, Fenton-like reaction, was used to extract lipid from the harvested biomass, and efficiency of 80% was obtained with 0.5% H2O2 at 90 degrees C. The iron compound was also employed in the esterification step, and converted free fatty acids to fatty acid methyl esters under acidic conditions; thus, the fatal problem of saponification during esterification with alkaline catalysts was avoided, and esterification efficiency over 90% was obtained. This study clearly showed that FeCl3 in the harvesting process is beneficial in all downstream steps and have a potential to greatly reduce the production cost of microalgae-originated biodiesel. (C) 2015 Elsevier Ltd. All rights reserved.
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  158. Functionalized Fe3O4@ Silica Core-Shell Nanoparticles as Microalgae Harvester and Catalyst for Biodiesel Production
    Abstract

    Chiang, Y. D.; Dutta, S.; Chen, C. T.; Huang, Y. T.; Lin, K. S.; Wu, J. C. S.; Suzuki, N.; Yamauchi, Y.; Wu, K. C. W. 2015. Functionalized Fe3O4@ Silica Core-Shell Nanoparticles as Microalgae Harvester and Catalyst for Biodiesel Production. Chemsuschem. 8(5) 789-794

    Core-shell Fe3O4@silica magnetic nanoparticles functionalized with a strong base, triazabicyclodecene (TBD), were successfully synthesized for harvesting microalgae and for one-pot microalgae-to-fatty acid methyl ester (FAME, or so-called biodiesel) conversion. Three types of algae oil sources (i.e., dried algae, algae oil, and algae concentrate) were used and the reaction conditions were optimized to achieve the maximum biodiesel yield. The results obtained in this study show that our TBD-functionalized Fe3O4@silica nanoparticles could effectively convert algae oil to biodiesel with a maximum yield of 97.1%. Additionally, TBD-Fe3O4@silica nanoparticles act as an efficient algae harvester because of their adsorption and magnetic properties. The method presented in this study demonstrates the wide scope for the use of covalently functionalized core-shell nanoparticles for the production of liquid transportation fuels from algal biomass.
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  159. Functionalized Fe3O4@silica core-shell nanoparticles as microalgae harvester and catalyst for biodiesel production
    Abstract

    Chiang, Y. D.; Dutta, S.; Chen, C. T.; Huang, Y. T.; Lin, K. S.; Wu, J. C.; Suzuki, N.; Yamauchi, Y.; Wu, K. C. 2015. Functionalized Fe3O4@silica core-shell nanoparticles as microalgae harvester and catalyst for biodiesel production. ChemSusChem. 8(5) 789-94

    Core-shell Fe3O4@silica magnetic nanoparticles functionalized with a strong base, triazabicyclodecene (TBD), were successfully synthesized for harvesting microalgae and for one-pot microalgae-to-fatty acid methyl ester (FAME, or so-called biodiesel) conversion. Three types of algae oil sources (i.e., dried algae, algae oil, and algae concentrate) were used and the reaction conditions were optimized to achieve the maximum biodiesel yield. The results obtained in this study show that our TBD-functionalized Fe3O4@silica nanoparticles could effectively convert algae oil to biodiesel with a maximum yield of 97.1 %. Additionally, TBD-Fe3O4@silica nanoparticles act as an efficient algae harvester because of their adsorption and magnetic properties. The method presented in this study demonstrates the wide scope for the use of covalently functionalized core-shell nanoparticles for the production of liquid transportation fuels from algal biomass.
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  160. Green integrated process for mitigation of municipal and industrial liquid and solid waste mixes for enhanced microalgal biomass and lipid synthesis for biodiesel
    Abstract

    Karemore, A.; Sen, R. 2015. Green integrated process for mitigation of municipal and industrial liquid and solid waste mixes for enhanced microalgal biomass and lipid synthesis for biodiesel. Rsc Advances. 5(87) 70929-70938

    Wastewater management has become one of the critical environmental challenges, as waste effluents from municipalities and industries including livestock farms are released into the environment resulting in the deterioration of water ecology, if left untreated. Through this study, we have developed a microalgae mediated green integrated process for wastewater remediation, while simultaneously producing biomass as potentially sustainable feedstock for biofuels. Chlorococcum sp. was cultivated in different types of wastewater and tested for nutrient remediation efficacy as well as biomass production. The results with respect to nutrient removal capacity in wastewater were encouraging as nitrogen was almost completely remediated, whereas removal percentages for carbon and phosphorous were between 67 and 89%. The results obtained using waste mixtures of wastewater effluents and poultry litter waste indicates substantial gain in microalgal biomass yield, an increase of more than 1.5-fold was observed as opposed to unsupplemented use. The obtained experimental microalgal growth data were fitted with a logistic growth model and found to provide a good fit between predicted values and investigated values. Furthermore, the lipid accumulation was enhanced by 2-fold in waste mixtures when compared to standard medium, and the lipids were mainly composed of C16 and C18 fatty acids, which are considered favourable for good-quality biodiesel. The strategy adopted in this study served the dual purpose of waste management and microalgal biomass production for biofuel application, thus making the entire process cost-effective and green.
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  161. Growth of microalgae using CO2 enriched air for biodiesel production in supercritical CO2
    Abstract

    Taher, H.; Al-Zuhair, S.; Al-Marzouqi, A.; Haik, Y.; Farid, M. 2015. Growth of microalgae using CO2 enriched air for biodiesel production in supercritical CO2. Renewable Energy. 8261-70

    The optimum conditions for lipids productivity and CO2 fixation of two freshwater strains, namely Chlorella sp. and Pseudochlorococcum sp. and a marine strain; namely Nannochlorpsis sp. have been determined in this work. The species were grown autotrophically under aeration with different CO2 concentrations, ranging from 0.04 to 2% (v/v). The growth was tested in nitrogen sufficient and deficient media at different salinities (0.49-680 mM) and temperatures of 27 and 31 degrees C. The optimum CO2 enrichment was found to be 1% (v/v) in both media. Nitrogen starvation resulted in an increase in lipid 'contents, but at lower growth rate, which resulted in a lower overall lipid productivity. The experimental data were used to determine the kinetic parameters of Haldane model. The Chlorella sp. grew well at salinity levels of up to 460 mM. The highest CO2 biofixation rate was observed when Chlorella sp. was grown at 27 degrees C in seawater (230 mM NaCl).
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  162. Harvesting cheap algal biodiesel
    Abstract

    Evans, J. 2015. Harvesting cheap algal biodiesel. Biofuels Bioproducts & Biorefining-Biofpr. 9(2) 128-128

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  163. Harvesting green algae from eutrophic reservoir by electroflocculation and post-use for biodiesel production
    Abstract

    Valero, E.; Alvarez, X.; Cancela, A.; Sanchez, A. 2015. Harvesting green algae from eutrophic reservoir by electroflocculation and post-use for biodiesel production. Bioresource Technology. 187255-262

    Each year there are more frequent blooms of green algae and cyanobacteria, representing a serious environmental problem of eutrophication. Electroflocculation (EF) was studied to harvest the algae which are present in reservoirs, as well as different factors which may influence on the effectiveness of the process: the voltage applied to the culture medium, run times, electrodes separation and natural sedimentation. Finally, the viability of its use to obtain biodiesel was studied by direct transesterification. The EF process carried out at 10 V for 1 min, with an electrode separation of 5.5 cm and a height of 4 cm in culture vessel, obtained a recovery efficiency greater than 95%, and octadecenoic and palmitic acids were obtained as the fatty acid methyl esters (FAMEs). EF is an effective method to harvest green algae during the blooms, obtaining the greatest amount of biomass for subsequent use as a source of biodiesel. (C) 2015 Elsevier Ltd. All rights reserved.
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  164. Heterotrophic and mixotrophic cultivation of microalgae for biodiesel production in agricultural wastewaters and associated challenges-a critical review
    Abstract

    Lowrey, J.; Brooks, M. S.; McGinn, P. J. 2015. Heterotrophic and mixotrophic cultivation of microalgae for biodiesel production in agricultural wastewaters and associated challenges-a critical review. Journal of Applied Phycology. 27(4) 1485-1498

    Many studies have demonstrated that heterotrophic and mixotrophic growth for various microalgae species yields greater biomass and lipid content as compared to photoautotrophic cultivation. This review explores the possibility of leveraging the natural ability of the microorganisms to metabolize carbon heterotrophically and mixotrophically in agricultural wastewaters. This has the potential advantage of improving the overall economics for the production of biodiesel and value-added biomolecules from microalgae, mitigating an existing waste stream and minimizing water requirements. However, there are a number of challenges and gaps in scientific knowledge that suggest a need for ongoing research in the area. In this review, specific focus is dedicated to the metabolic mechanisms, reported performances, and practical challenges that contribute to the uncertainty of employing agricultural wastewaters for heterotrophic and mixotrophic microalgae cultures.
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  165. Heterotrophic microalgae cultivation to synergize biodiesel production with waste remediation: Progress and perspectives
    Abstract

    Mohan, S. V.; Rohit, M. V.; Chiranjeevi, P.; Chandra, R.; Navaneeth, B. 2015. Heterotrophic microalgae cultivation to synergize biodiesel production with waste remediation: Progress and perspectives. Bioresource Technology. 184169-178

    Microalgae are inexhaustible feedstock for synthesis of biodiesel rich in polyunsaturated fatty acids (PUFA) and valuable bioactive compounds. Their cultivation is critical in sustaining the global economy in terms of human consumption of food and fuel. When compared to autotrophic cultivation, heterotrophic systems are more suitable for producing high cell densities of microalgae for accumulation of large quantities of lipids (triacylglycerols) which can be converted into biodiesel. Consorted efforts are made in this communication to converge recent literature on heterotrophic cultivation systems with simultaneous wastewater treatment and algal oil production. Challenges faced during large scale production and limiting factors which hinder the microalgae growth are enumerated. A strategic deployment of integrated closed loop biorefinery concept with multi-product recovery is proposed to exploit the full potential of algal systems. Sustainable algae cultivation is essential to produce biofuels leading to green future. (C) 2014 Elsevier Ltd. All rights reserved.
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  166. High-purity biodiesel production from microalgae and added-value lipid extraction: a new process
    Abstract

    Veillette, M.; Giroir-Fendler, A.; Faucheux, N.; Heitz, M. 2015. High-purity biodiesel production from microalgae and added-value lipid extraction: a new process. Applied Microbiology and Biotechnology. 99(1) 109-119

    A new process was tested in order to produce and purify biodiesel from microalgae lipids and to recover unsaponifiable (added-value) lipids. This process is a two-step biodiesel production including a saponification reaction step followed by an esterification reaction step. The process includes a recovery of the unsaponified lipids between both reaction steps. Among the conditions tested, the following conditions were found to be the best: temperature for both steps (90 A degrees C), saponification time (30 min), esterification time (30 min), sulfuric acid/potassium hydroxide (1.21, w/w), and methanol-lipid ratio (13.3 mL/g). Under these conditions, the fatty acid methyl ester (FAME) yield and the biodiesel purity were, respectively, 32 % (g FAME/g lipid) and 77 % (g FAME/g biodiesel). This study also showed that the two-step biodiesel process allows a FAME mass composition rich in palmitate (27.9-29.4 wt%), palmitoleate (24.9-26.0 wt%), elaidate (14.8-15.2 wt%), and myristate (12.1-13.0 wt%).
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  167. Isolation and characterization of microalgae for biodiesel production from seawater
    Abstract

    Zhao, L.; Qi, Y.; Chen, G. Y. 2015. Isolation and characterization of microalgae for biodiesel production from seawater. Bioresource Technology. 18442-46

    As green marine microalgae isolated from local seawater in Tianjin, China, Nannochloropsis gaditana Q6 was tolerant to the variation of salinity with the highest biomass and lipid concentration in natural seawater medium. Although this strain could grow mixotrophically with glycerol, the narrow gap between mixotrophic and autotrophic cultivation suggested that autotrophic cultivation was the optimal trophic type for N. gaditana Q6 growth. In addition, strain Q6 was more sensitive to the variance of NH4HCO3 concentration than NaH2PO4 concentration. Consequently, the lipid production could be maximized by the two-stage cultivation strategy, with an initial high NH4HCO3 concentration for biomass production followed by low NH4HCO3 concentration for lipid accumulation. (C) 2014 Elsevier Ltd. All rights reserved.
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  168. Isolation, Mutagenesis, and Optimization of Cultivation Conditions of Microalgal Strains for Biodiesel Production (vol 61, pg 124, 2014)
    Abstract

    Zayadan, B. K.; Sadvakasova, A. K.; Userbaeva, A. A.; Bolatkhan, K. 2015. Isolation, Mutagenesis, and Optimization of Cultivation Conditions of Microalgal Strains for Biodiesel Production (vol 61, pg 124, 2014). Russian Journal of Plant Physiology. 62(3) 424-424

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  169. Kinetic modeling of microalgal growth and lipid synthesis for biodiesel production
    Abstract

    Surendhiran, D.; Vijay, M.; Sivaprakash, B.; Sirajunnisa, A. 2015. Kinetic modeling of microalgal growth and lipid synthesis for biodiesel production. 3 Biotech. 5(5) 663-669

    A mathematical modeling of microalgae biomass is an essential step to optimize the biomass and lipid production rate and to reduce the cost of microalgal biodiesel production system. In the present study, kinetic studies were carried out to describe the growth and neutral lipid production of two marine microalgae Chlorella salina and Nannochloropsis oculata under the nitrogen-repleted and -depleted conditions using logistic and Luedeking-Piret equations. This research paper provides the information on mathematically efficient procedure to predict suitable environment condition for biomass and lipid production. The predicted results were compared with experimental data, which showed that this model closely agreed with simulated results. From this investigation, it was found that nitrogen was an essential nutrient for algal growth, which increased under nitrogen-rich condition, whereas during nitrogen-limited condition some loss in growth was observed but with increased lipid content. Since metabolic changes occurred under nitrogen- depleted state, the protein and carbohydrate pathways were shifted to lipid biosynthesis.
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  170. Life cycle analysis on fossil energy ratio of algal biodiesel: effects of nitrogen deficiency and oil extraction technology
    Abstract

    Jian, H.; Jing, Y.; Peidong, Z. 2015. Life cycle analysis on fossil energy ratio of algal biodiesel: effects of nitrogen deficiency and oil extraction technology. ScientificWorldJournal. 2015920968

    Life cycle assessment (LCA) has been widely used to analyze various pathways of biofuel preparation from "cradle to grave." Effects of nitrogen supply for algae cultivation and technology of algal oil extraction on life cycle fossil energy ratio of biodiesel are assessed in this study. Life cycle fossil energy ratio of Chlorella vulgaris based biodiesel is improved by growing algae under nitrogen-limited conditions, while the life cycle fossil energy ratio of biodiesel production from Phaeodactylum tricornutum grown with nitrogen deprivation decreases. Compared to extraction of oil from dried algae, extraction of lipid from wet algae with subcritical cosolvents achieves a 43.83% improvement in fossil energy ratio of algal biodiesel when oilcake drying is not considered. The outcome for sensitivity analysis indicates that the algal oil conversion rate and energy content of algae are found to have the greatest effects on the LCA results of algal biodiesel production, followed by utilization ratio of algal residue, energy demand for algae drying, capacity of water mixing, and productivity of algae.
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  171. Lipid content and fatty acid composition of Mediterranean macro-algae as dynamic factors for biodiesel production
    Abstract

    El Maghraby, D. M.; Fakhry, E. M. 2015. Lipid content and fatty acid composition of Mediterranean macro-algae as dynamic factors for biodiesel production. Oceanologia. 57(1) 86-92

    Using the total lipid contents and fatty acid profiles, the marine macro-algae Jania rubens (Rhodophyceae), Ulva linza (Chlorophyceae) and Padina pavonica (Phaeophyceae) were evaluated for biodiesel production during the spring, summer and autumn. Seawater parameters such as pH, salinity and temperature were measured. The total lipid content varied from 1.56% (J. rubens) to 4.14% (U. linza) of dry weight, with the highest values occurring in spring. The fatty acid methyl ester profiles were analysed using gas chromatography. The highest percentage of total fatty acids was recorded in P pavonica, with 6.2% in autumn, whereas the lowest was in J. rubens, with 68.6% in summer. The relative amount of saturated to unsaturated fatty acids was significantly higher in P pavonica than in the other macro-algae. Seasonal variations in pH, salinity and temperature had no significant effect on the total lipid and fatty acid contents. Principal component analysis grouped brown and green algae together, whereas red alga grouped out. Furthermore, methyl ester profiles indicate that brown and green seaweeds are preferred, followed by red seaweeds, which appears to have little potential for oil-based products. Therefore, these seaweeds are not targets for biodiesel production. (C) 2014 Institute of Oceanology of the Polish Academy of Sciences. Production and hosting by Elsevier Urban Et Partner Sp. z o.o. All rights reserved.
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  172. Lipid extraction and esterification for microalgae-based biodiesel production using pyrite (FeS2)
    Abstract

    Seo, Y. H.; Sung, M.; Oh, Y. K.; Han, J. I. 2015. Lipid extraction and esterification for microalgae-based biodiesel production using pyrite (FeS2). Bioresource Technology. 191420-425

    In this study, pyrite (FeS2) was used for lipid extraction as well as esterification processes for microalgae-based biodiesel production. An iron-mediated oxidation reaction, Fenton-like reaction, produced an expected degree of lipid extraction, but pyrite was less effective than FeCl3 commercial powder. That low efficiency was improved by using oxidized pyrite, which showed an equivalent lipid extraction efficiency to FeCl3, about 90%, when 20 mM of catalyst was used. Oxidized pyrite was also employed in the esterification step, and converted free fatty acids to fatty acid methyl esters under acidic conditions; thus, the fatal problem of saponification during esterification with alkaline catalysts was avoided, and esterification efficiency over 90% was obtained. This study clearly showed that pyrite could be utilized as a cheap catalyst in the lipid extraction and esterification steps for microalgae-based biodiesel production. (C) 2015 Elsevier Ltd. All rights reserved.
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  173. Lipid metabolism in response to individual short chain fatty acids during mixotrophic mode of microalgal cultivation: Influence on biodiesel saturation and protein profile
    Abstract

    Chandra, R.; Arora, S.; Rohit, M. V.; Mohan, S. V. 2015. Lipid metabolism in response to individual short chain fatty acids during mixotrophic mode of microalgal cultivation: Influence on biodiesel saturation and protein profile. Bioresource Technology. 188169-176

    Critical influence of different short chain fatty acids as organic carbon source, during growth (GP) and nutrient stress lipogenic phase (NSLP) was investigated on biomass and lipid productivity, in mixotrophic fed-batch microalgae cultivation. Nutrient deprivation induced physiological stress stimulated highest lipid productivity with acetate (total/neutral lipids, 35/17) with saturation index of 80.53% by the end of NSLP followed by butyrate (12/7%; 78%). Biomass growth followed the order of acetate (2.23 g/l) >buty-rate (0.99 g/l) >propionate (0.77 g/l). VFA removal (as COD) was maximum with acetate (87%) followed by butyrate (55.09%) and propionate (10.60%). Palmitic acid was the most dominant fatty acid found in the fatty acid composition of all variants and butyrate fed system yielded a maximum of 44% palmitic acid. Protein profiling illustrated prominence of acetyl CoA-synthetase activity in acetate system. Thus, fatty acids provide a promising alternative feedstock for biodiesel production with integrated microalgae-biorefinery. (C) 2015 Elsevier Ltd. All rights reserved.
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  174. Low algal diversity systems are a promising method for biodiesel production in wastewater fed open reactors
    Abstract

    Bhattacharjee, M.; Siemann, E. 2015. Low algal diversity systems are a promising method for biodiesel production in wastewater fed open reactors. Algae. 30(1) 67-79

    Planktivorous fish which limit zooplankton grazing have been predicted to increase algal biodiesel production in wastewater fed open reactors. In addition, tanks with higher algal diversity have been predicted to be more stable, more productive, and to more fully remove nutrients from wastewater. To test these predictions, we conducted a 14-week experiment in Houston, TX using twelve 2,270-L open tanks continuously supplied with wastewater. Tanks received algal composition (monocultures or diverse assemblage) and trophic (fish or no fish) treatments in a full-factorial design. Monocultures produced more algal and fatty acid methyl ester (FAME) mass than diverse tanks. More than 80% of lipids were converted to FAME indicating potentially high production for conversion to biodiesel (up to 0.9 T ha(-1) y(-1)). Prolific algal growth lowered temperature and levels of total dissolved solids in the tanks and increased pH and dissolved oxygen compared to supply water. Algae in the tanks removed 91% of nitrate-N and 53% of phosphorus from wastewater. Monocultures were not invaded by other algal species. Fish did not affect any variables. Our results indicated that algae can be grown in open tank bioreactors using wastewater as a nutrient source. The stable productivity of monocultures suggests that this may be a viable production method to procure algal biomass for biodiesel production.
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  175. Low-cost solid catalyst derived from waste Cyrtopleura costata (Angel Wing Shell) for biodiesel production using microalgae oil
    Abstract

    Syazwani, O. N.; Rashid, U.; Yap, Y. H. T. 2015. Low-cost solid catalyst derived from waste Cyrtopleura costata (Angel Wing Shell) for biodiesel production using microalgae oil. Energy Conversion and Management. 101749-756

    In the present work, Cyrtopleura costata (Angel Wing Shell) is used for the first time to synthesis of CaO. The produced CaO was utilized as a catalyst for biodiesel production from microalgae Nannochloropsis oculata oil. The Angel Wing Shell (AWS) was calcined at 800 degrees C and 900 degrees C for 2 h to convert CaCO3 to activate metal oxide phase. The synthesized catalysts were characterized by using Thermogravimetric analysis (TGA), X-ray diffraction (XRD), Temperature programmed desorption of CO2 (CO2-TPD), BET surface area and Scanning electron microscopy (SEM) analysis. The calcined Angel Wing Shell at 900 degrees C (CAWS 900) was chosen as the best catalyst due to its high basicity and surface area. This also corresponded to optimization condition where, CAWS 900 showed highest FAME yield (84.11%) at oil to methanol molar ratio 1:150 and catalyst loading of 9 wt.% in 1 h reaction time. The CAWS 900 catalyst also can be reused more than three times with FAME yield greater than 65%. Overall, AWS appears to be an acceptable solid catalyst to convert microalgae oil to biodiesel. (C) 2015 Elsevier Ltd. All rights reserved.
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  176. Microalgae cultivation in urban wastewater: Nutrient removal and biomass production for biodiesel and methane
    Abstract

    Caporgno, M. P.; Taleb, A.; Olkiewicz, M.; Font, J.; Pruvost, J.; Legrand, J.; Bengoa, C. 2015. Microalgae cultivation in urban wastewater: Nutrient removal and biomass production for biodiesel and methane. Algal Research-Biomass Biofuels and Bioproducts. 10232-239

    The freshwater microalgae species Chlorella kessleri and Chlorella vulgaris, and the marine microalgae species Nannochloropsis oculata were cultivated in urban wastewater. The freshwater species demonstrated the possibility of growing in urban wastewater reaching high biomass production and nutrient removal when cultured in batch mode using a flat-panel airlift photobioreactor. Both microalgae species reached high biomass dry weights, 2.70 +/- 0.08 g/L and 2.91 +/- 0.02 g/L respectively, accompanied by nitrogen concentration reduction around 96% and 95%, and a phosphorous concentration reduction around 99% and 98% respectively. N. oculata was able to uptake nutrients from wastewater to grow but with less efficiency, indicating the need of microalgae acclimation or process optimisation to achieve high nutrient removals. During C. kessleri and C. vulgaris cultivation, the nitrogen consumption led to a progressive N-starvation process which increased the microalgae potential for biofuels production; both species produced 346 +/- 3 mL(CH4)/g(VS) and 415 +/- 2 mL(CH4)/g(VS) during anaerobic digestion, and 7.4 +/- 0.2 g(Biodiesel)/100 g(VS) and 11.3 +/- 0.1 g(Biodiesel)/100 g(VS) respectively. (C) 2015 Elsevier B.V. All rights reserved.
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  177. Microwave treatment of wet algal paste for enhanced solvent extraction of lipids for biodiesel production
    Abstract

    Ali, M.; Watson, I. A. 2015. Microwave treatment of wet algal paste for enhanced solvent extraction of lipids for biodiesel production. Renewable Energy. 76470-477

    The role of microwave treatment as a precursor to lipid extraction from Nannochloropsis oculata using solvent extraction was investigated. Two microwave power settings were used, corresponding to wall plug powers of 635 and 1021 W. To limit the maximum temperature rise of the wet algal samples, exposure times were capped to 15 s intervals and followed by 15 min of cooling. Samples were treated in total from 1 to 5 min of microwave treatment (i.e. 1 min was 4 x 15 s treatments). The lysed fraction increased with exposure time for both power levels and the extracted lipids closely followed the lysed fraction. The highest extracted lipid content, after 5 min, was 0.036 g/g dry algae weight (g/g) for 635 W (68.86% cell lysis), while with 1021 W the yield was 0.052 g/g (92.81%). The control sample, which did not receive any microwave treatment, was only 0.016 g/g dry algae weight. Significance was observed between treatment time, cell lysis and lipid yield, (p<0.05). For the 5 min of treatment, the lipid produced per total number of Joules consumed was found for each microwave power setting; yielding values of 1.889 x 10(-4) g/g/kJ (635 W) and 1.697 x 10(-4) g/g/kJ (1021 W). (C) 2014 Elsevier Ltd. All rights reserved.
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  178. Optimal Design of Algae Biorefinery Processing Networks for the production of Protein, Ethanol and Biodiesel
    Abstract

    Cheali, P.; Vivion, A.; Gernaey, K. V.; Sin, G. 2015. Optimal Design of Algae Biorefinery Processing Networks for the production of Protein, Ethanol and Biodiesel. 12th International Symposium on Process Systems Engineering (Pse) and 25th European Symposium on Computer Aided Process Engineering (Escape), Pt B. 371151-1156

    In this study, optimal design of algal biorefinery using microalgae with respect to techno-economic criteria is studied. A systematic methodology using superstructure-based optimization is used to this end. A superstructure representing a wide range of technologies developed for processing microalgae to produce end products is formulated. The corresponding technical and economic data is collected and structured using a generic input-output mass balance models. An optimization problem is formulated and solved to identify the optimal designs. The effect of uncertainties inherent in economic analysis such as microalgae production cost, composition of microalgae (e.g. oil content) and biodiesel/bioethanol market prices is considered. New optimal processing paths are found with potential of producing higher amount of biodiesel. Last, the methodology is intended as decision support tool for early-stage concept screening to enhance the future development of algal biorefinery.
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  179. Optimization of process configuration and strain selection for microalgae-based biodiesel production
    Abstract

    Yu, N.; Dieu, L. T. J.; Harvey, S.; Lee, D. Y. 2015. Optimization of process configuration and strain selection for microalgae-based biodiesel production. Bioresource Technology. 19325-34

    A mathematical model was developed for the design of microalgae-based biodiesel production system by systematically integrating all the production stages and strain properties. Through the hypothetical case study, the model suggested the most economical system configuration for the selected microalgae strains from the available processes at each stage, thus resulting in the cheapest biodiesel production cost, S$2.66/kg, which is still higher than the current diesel price (S$1.05/kg). Interestingly, the microalgae strain properties, such as lipid content, effective diameter and productivity, were found to be one of the major factors that significantly affect the production cost as well as system configuration. (C) 2015 Elsevier Ltd. All rights reserved.
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  180. Process integration for microalgal lutein and biodiesel production with concomitant flue gas CO2 sequestration: a biorefinery model for healthcare, energy and environment
    Abstract

    Dineshkumar, R.; Dash, S. K.; Sen, R. 2015. Process integration for microalgal lutein and biodiesel production with concomitant flue gas CO2 sequestration: a biorefinery model for healthcare, energy and environment. Rsc Advances. 5(90) 73381-73394

    In this study, a green microalgal feedstock based biorefinery was developed by process optimization and integration with a view to sequestering flue gas CO2 and synthesizing lutein and lipid for environmental, healthcare and biofuel applications, respectively. Out of the four microalgal cultures tested in a 2 L airlift photobioreactor, Chlorella minutissima showed comparatively higher productivities of both lutein (2.37 +/- 0.08 mg L-1 d(-1)) and lipid (84.3 +/- 4.1 mg L-1 d(-1)). Upon optimization of the critical process parameters using artificial neural network modeling and the particle swarm optimization (ANN-PSO) technique, the productivities of lutein and lipid were enhanced to 4.32 +/- 0.11 mg L-1 d(-1) and 142.2 +/- 5.6 mg L-1 d(-1) respectively, using pure CO2 sequestered at a rate of 1.2 +/- 0.03 g L-1 d(-1). One of the most interesting findings was that the lutein and lipid productivities were not significantly affected by the use of toxic flue-gas, when diluted to 3.5% CO2 with air, under the same process conditions, suggesting the possible commercial usefulness of flue-gas carbon. Another major achievement is that a single step ethanol-hexane based extraction procedure, followed by parallel saponification and trans-esterification, resulted in the simultaneous recovery of 94.3% lutein and 92.4% fatty acid methyl ester. Therefore, the potential industrial significance of this study lies in the development of an integrated biorefinery that may prove to be a sustainable technology platform towards addressing some contemporary challenges in healthcare, energy and environment through concomitant production of microalgal lutein as a nutraceutical and biodiesel as an alternative fuel, coupled with flue gas CO2 sequestration.
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  181. Production of a methyl ester from the microalgae Nannochloropsis grown in raceways on the French west coast
    Abstract

    Perrier, B.; Crampon, C.; Guezet, O.; Simon, C.; Maire, F.; Lepine, O.; Pruvost, J.; Lozano, P.; Bernard, O.; Badens, E. 2015. Production of a methyl ester from the microalgae Nannochloropsis grown in raceways on the French west coast. Fuel. 153640-649

    The present article describes the production of oil from autotrophic microalgae grown in raceways in France, and presents the bench test results of a Diesel monocylinder engine with the derived biodiesel (methyl ester).
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  182. Production of biodiesel from coastal macroalgae (Chara vulgaris) and optimization of process parameters using Box-Behnken design
    Abstract

    Siddiqua, S.; Mamun, A. A.; Enayetul Babar, S. M. 2015. Production of biodiesel from coastal macroalgae (Chara vulgaris) and optimization of process parameters using Box-Behnken design. Springerplus. 4720

    Renewable biodiesels are needed as an alternative to petroleum-derived transport fuels, which contribute to global warming and are of limited availability. Algae biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuels. This study introduces an integrated method for the production of biodiesel from Chara vulgaris algae collected from the coastal region of Bangladesh. The Box-Behnken design based on response surface methods (RSM) used as the statistical tool to optimize three variables for predicting the best performing conditions (calorific value and yield) of algae biodiesel. The three parameters for production condition were chloroform (X1), sodium chloride concentration (X2) and temperature (X3). Optimal conditions were estimated by the aid of statistical regression analysis and surface plot chart. The optimal condition of biodiesel production parameter for 12 g of dry algae biomass was observed to be 198 ml chloroform with 0.75 % sodium chloride at 65 degrees C temperature, where the calorific value of biodiesel is 9255.106 kcal/kg and yield 3.6 ml.
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  183. Production of Biodiesel from Marine Algae to Mitigate Environmental Pollution
    Abstract

    Khan, A. M.; Obaid, M.; Sultana, R. 2015. Production of Biodiesel from Marine Algae to Mitigate Environmental Pollution. Journal of the Chemical Society of Pakistan. 37(3) 612-620

    This research article demonstrates the conversion of oily contents of marine macroalgae, namely Cystoseira indica and Scinia hatei to fatty acid methyl ester (FAME) through alkaline transesterification. The algae were dried, crushed and grinded into the powder form, which were analyzed for physical appearance, water content and particle size profile. The oily contents from these powdered algae were extracted by using different non-polar solvents like n-hexane, n-heptane, dichloromethane, diethyl ether and n-hexane: diethyl ether (1: 1) mixture at small scale. The efficiency index of the solvent was developed based on the yield of the oily content and boiling point of these solvents, which showed that n-hexane: diethyl ether (1: 1) mixture is the best solvent system for the extraction of oils. The yield of oily contents with respect to the dried algal weight was found to be 2.81 +/- 0.43 % w/w and 3.10 +/- 0.27 % w/w for C. indica and S. hatei respectively. These oily contents were subjected to physical and chemical analysis. The oily contents were converted into biodiesel by alkaline transesterification using potassium methoxide as catalyst which is prepared by dissolving KOH in methanol (0.5g/12 ml, 4.2% w/v) in a separate flask. All the reactions were carried out under completely anhydrous conditions using silica as desiccant and with continuous stirring so that the reactants in two immiscible phases of oily contents and methanol were remain in contact. The yield of biodiesel was found to be 89.0 +/- 0.51 % w/w (2.50 % w/w of dried alga) and 90.6 +/- 0.36 % w/w (2.81 % w/w of dried alga) of biodiesel from C. indica and S. hatei respectively. Finally, biodiesel was characterized by gas chromatography and American Society for Testing and Materials (ASTM) as well as by European (EN) standards which were found to be in agreement with the standard values of biodiesel.
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  184. Production of biodiesel from microalgae oil (Chlorella protothecoides) by non-catalytic transesterification in supercritical methanol and ethanol: Process optimization
    Abstract

    Nan, Y.; Liu, J. X.; Lin, R. H.; Tavlarides, L. L. 2015. Production of biodiesel from microalgae oil (Chlorella protothecoides) by non-catalytic transesterification in supercritical methanol and ethanol: Process optimization. Journal of Supercritical Fluids. 97174-182

    Production of biodiesel through non-catalytic transesterification of microalgae oil in supercritical methanol and ethanol was studied. The response surface methodology (RSM) combined with a five-parameter-five-level central composite design (CCD) was employed to optimize the (270-350 degrees C), pressure (80-200 bar), alcohol-to-oil molar ratio (10:1-42:1), residence time (10-50 min) and water content (0-10 wt%). Thirty-two experiments were designed and conducted for each alcohol species. Quadratic models were built based on the yields of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs). Optimal conditions and yields for FAMEs and FAEEs were predicted with the models, and model predictions were verified by additional independent experiments conducted under predicted optimal conditions. Optimal biodiesel yields obtained in this work were 90.8% and 87.8% with methanol and ethanol, respectively. The significance of the parameters was evaluated by the analysis of variance (ANOVA). The effects of single parameters and the interacted parameters on the biodiesel yield were also discussed. (C) 2014 Elsevier B.V. All rights reserved.
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  185. Production of biodiesel from microalgae oil (Chlorella protothecoides) by non-catalytic transesterification: Evaluation of reaction kinetic models and phase behavior
    Abstract

    Liu, J. X.; Lin, R. H.; Nan, Y.; Tavlarides, L. L. 2015. Production of biodiesel from microalgae oil (Chlorella protothecoides) by non-catalytic transesterification: Evaluation of reaction kinetic models and phase behavior. Journal of Supercritical Fluids. 9938-50

    The non-catalytic transesterification of microalgae oil with methanol was conducted at 300-400 degrees C, 150-300 bar, methanol-to-oil molar ratio (MOMR) of 6-12, and residence time of 0.5-10 min. A visualization system was built to study the phase transition, and it shows that at the conditions (T: 300-400 degrees C, P: 200 bar, tau: 0.5-10 min, MOMR of 9), the reactions were performed in homogeneous state. The dynamic phase behavior of the reacting systems was also investigated by RK-Aspen Equation of State. The results indicate that at 200 bar, MOMR of 9, and 300-385 degrees C, the reacting mixtures were in liquid state and moved toward supercritical region, while at 400 degrees C the reacting system was initially in liquid state and quickly approached supercritical state due to the fast reaction conversion. The critical points of the reaction mixtures were estimated. Ten commonly used kinetic models were evaluated, and it shows that three-step, reversible second-order model worked best in the data fitting. Reaction rate constants and activation energies for selected models were determined and compared with literature data. (C) 2015 Elsevier B.V. All rights reserved.
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  186. Production of biodiesel from vegetable oil and microalgae by fatty acid extraction and enzymatic esterification
    Abstract

    Castillo Lopez, B.; Esteban Cerdan, L.; Robles Medina, A.; Navarro Lopez, E.; Martin Valverde, L.; Hita Pena, E.; Gonzalez Moreno, P. A.; Molina Grima, E. 2015. Production of biodiesel from vegetable oil and microalgae by fatty acid extraction and enzymatic esterification. J Biosci Bioeng. 119(6) 706-11

    The aim of this work was to obtain biodiesel (methyl esters) from the saponifiable lipids (SLs) fraction of the microalga Nannochloropsis gaditana, whose biomass dry weight contains 12.1 wt% of these lipids. SLs were extracted from the microalga as free fatty acids (FFAs) for subsequent transformation to methyl esters (biodiesel) by enzymatic esterification. Extraction as FFAs rather than as SLs allows them to be obtained with higher purity. Microalgal FFAs were obtained by direct saponification of lipids in the biomass and subsequent extraction-purification with hexane. Esterification of FFAs with methanol was catalysed by lipase Novozym 435 from Candida antarctica. Stability studies of this lipase in the operational conditions showed that the esterification degree (ED) attained with the same batch of lipase remained constant over six reaction cycles (36 h total reaction time). The optimal conditions attained for 4 g of FFAs were 25 degrees C, 200 rpm, methanol/FFA molar ratio of 1.5:1, Novozym 435/FFA ratio of 0.025:1 w/w and 4 h reaction time. In these conditions the ED attained was 92.6%, producing a biodiesel with 83 wt% purity from microalgal FFAs. Several experimental scales were tested (from 4 to 40 g FFAs), and in all cases similar EDs were obtained.
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  187. Production of biodiesel from vegetable oil and microalgae by fatty acid extraction and enzymatic esterification
    Abstract

    Lopez, B. C.; Cerdan, L. E.; Medina, A. R.; Lopez, E. N.; Valverde, L. M.; Pena, E. H.; Moreno, P. A. G.; Grima, E. M. 2015. Production of biodiesel from vegetable oil and microalgae by fatty acid extraction and enzymatic esterification. Journal of Bioscience and Bioengineering. 119(6) 706-711

    The aim of this work was to obtain biodiesel (methyl esters) from the saponifiable lipids (Rs) fraction of the microalga Nannochloropsis gaditana, whose biomass dry weight contains 12.1 wt% of these lipids. SLs were extracted from the microalga as free fatty acids (FFAs) for subsequent transformation to methyl esters (biodiesel) by enzymatic esterification. Extraction as FFAs rather than as SLs allows them to be obtained with higher purity. Microalgal FFAs were obtained by direct saponification of lipids in the biomass and subsequent extraction-purification with hexane. Esterification of FFAs with methanol was catalysed by lipase Novozym 435 from Candida antarctica. Stability studies of this lipase in the operational conditions showed that the esterification degree (ED) attained with the same batch of lipase remained constant over six reaction cycles (36 h total reaction time). The optimal conditions attained for 4 g of FFAs were 25 degrees C, 200 rpm, methanol/FFA molar ratio of 1.5:1, Novozym 435/FFA ratio of 0.025:1 w/w and 4 h reaction time. In these conditions the ED attained was 92.6%, producing a biodiesel with 83 wt% purity from microalgal FFAs. Several experimental scales were tested (from 4 to 40 g FFAs), and in all cases similar EDs were obtained. (C) 2014, The Society for Biotechnology, Japan. All rights reserved.
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  188. Production of Jet Fuel Range Hydrocarbons as a Coproduct of Algal Biodiesel by Butenolysis of Long-Chain Alkenones
    Abstract

    O'Neil, G. W.; Culler, A. R.; Williams, J. R.; Burlow, N. P.; Gilbert, G. J.; Carmichael, C. A.; Nelson, R. K.; Swarthout, R. F.; Reddy, C. M. 2015. Production of Jet Fuel Range Hydrocarbons as a Coproduct of Algal Biodiesel by Butenolysis of Long-Chain Alkenones. Energy & Fuels. 29(2) 922-930

    Long-chain (35-40 carbons) alkenones are a unique class of lipids biosynthesized by certain species of algae including the industrially grown marine microalgae Isochrysis. Their structures are characterized by a very long linear carbon-chain with trans double bonds and a methyl or ethyl ketone. A method is presented for the isolation of pure alkenones from Isochrysis biomass in parallel with biodiesel production. Yields for the isolated alkenones and biodiesel relative to the starting dry Isochrysis biomass were routinely 3.5 and 12% (w/w), respectively. Alkenones were then converted to smaller hydrocarbon fragments (jet-fuel range) by cross-metathesis with 2-butene (butenolysis) using several commercial ruthenium-based metathesis initiators. Butenolysis with the second-generation Hoveyda-Grubbs catalyst occurred rapidly at 4 degrees C, yielding near quantitative conversion within 30 min to a mixture containing mostly 8-decen-2-one (C-10), 2,9-undecadiene (C-12), and 2-heptadecene (C-17) as both cis- and trans isomers based on analysis by comprehensive two-dimensional gas chromatography.
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  189. Prospects for biodiesel production from algae-based wastewater treatment in Brazil: A review
    Abstract

    Kligerman, D. C.; Bouwer, E. J. 2015. Prospects for biodiesel production from algae-based wastewater treatment in Brazil: A review. Renewable & Sustainable Energy Reviews. 521834-1846

    The modern world is highly dependent on energy. Biodiesel is recognized as a green and alternative renewable diesel fuel, and Brazil is the world's third largest producer of biodiesel, which in this country is mainly produced from soybeans. As the demand for biodiesel is increasing due to the increasing use of transportation fuel, it is advisable to look for other sources that would not need avast cropland. Recently, microalgae have emerged as a source than can play the dual role of bioremediation of wastewater and generation of biomass for biodiesel production. This paper focuses on the feasibility of utilizing wastewater to cultivate algae for the production of biodiesel in Brazil. By using only domestic wastewater from 40% of Brazilian municipalities, the production of biodiesel would increase by 21.4%. Moreover, the use of wastewater treatment becomes an economically attractive alternative as the revenue from selling biodiesel overcomes the production costs by at least 10%. As a result, Brazil could easily increase its current biodiesel production and simultaneously amazingly improve its index of sanitation. (c) 2015 Elsevier Ltd. All rights reserved.
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  190. Recent nanoparticle engineering advances in microalgal cultivation and harvesting processes of biodiesel production: A review
    Abstract

    Lee, Y. C.; Lee, K.; Oh, Y. K. 2015. Recent nanoparticle engineering advances in microalgal cultivation and harvesting processes of biodiesel production: A review. Bioresource Technology. 18463-72

    Among the various steps entailed in the production of biodiesel from microalgae, the efficiency and costreduction of the cultivation and harvesting steps remain key obstacles to its practical commercialization. Recently, in order to overcome the technical bottlenecks and limitations with regard to both steps, nanoparticle engineering based on particles' unique physico-chemical and mechanical properties has been extensively applied as a powerful analytical and practical tool. These applications include the enhancement of cell growth and/or pigments by light back-scattering, the induction of intracellular lipid accumulation by nutritional competition and/or stress environment, the improvement of cell separation efficiency and processing time from culture broth, the multiple reuse of magnetic nanoparticle flocculant, and integrated one-pot harvesting/cell-disruption. This review presents and discusses the recent nanoparticle- engineering-based developments in the implementation of practical microalgal cultivation and harvesting processes. (C) 2014 Elsevier Ltd. All rights reserved.
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  191. Reducing the life cycle GHG emissions of microalgal biodiesel through integration with ethanol production system
    Abstract

    Maranduba, H. L.; Robra, S.; Nascimento, I. A.; da Cruz, R. S.; Rodrigues, L. B.; Neto, J. A. D. 2015. Reducing the life cycle GHG emissions of microalgal biodiesel through integration with ethanol production system. Bioresource Technology. 19421-27

    Despite environmental benefits of algal-biofuels, the energy-intensive systems for producing microalgae-feedstock may result in high GHG emissions. Trying to overcome energy-costs, this research analyzed the biodiesel production system via dry-route, based on Chlorella vulgaris cultivated in race-ways, by comparing the GHG-footprints of diverse microalgae-biodiesel scenarios. These involved: the single system of biomass production (C0); the application of pyrolysis on the residual microalgal biomass (cake) from the oil extraction process (C1); the same as C0, with anaerobic cake co-digested with cattle manure (C2); the same conditions as in C1 and C2, by integrating in both cases (respectively C3 and C4), the microalgae cultivation with an autonomous ethanol distillery. The reduction of GHG emissions in scenarios with no such integration (C1 and C2), compared to CO, was insignificant (0.53% and 4.67%, respectively), whereas in the scenarios with integration with ethanol production system, the improvements were 53.57% for C3 and 63.84% for C4. (C) 2015 Elsevier Ltd. All rights reserved.
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  192. Selective esterification to produce microalgal biodiesel and enrich polyunsaturated fatty acid using zeolite as a catalyst
    Abstract

    Dong, T.; Yu, X. C.; Miao, C.; Rasco, B.; Garcia-Perez, M.; Sablani, S. S.; Chen, S. L. 2015. Selective esterification to produce microalgal biodiesel and enrich polyunsaturated fatty acid using zeolite as a catalyst. Rsc Advances. 5(103) 84894-84900

    Microalgae can be both a promising biofuel feedstock and a source of polyunsaturated fatty acids (PUFA). This paper reports a novel integrated process that simultaneously produces biodiesel and enriches PUFA. It was accomplished by using zeolite as a selective catalyst that preferentially converts shorter-chain fatty acids (SCFA) into fatty acid methyl esters (FAME) (86% conversion for S. limacinum and 65% conversion for N. salina) and enriches high-value PUFA (70% for S. limacinum and 78% for N. salina) in the unreacted free fatty acid (FFA) stream. The esterification reaction rate was affected by acid strength and pore size, while the selectivity of zeolite increased as pore size of zeolite decreased. This approach allows production of high quality biodiesel and efficient PUFA enrichment. The unreacted PUFA can be further refined for nutraceutical or other applications to improve economic viability of microalgal biodiesel production.
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  193. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine
    Abstract

    Parsaeimehr, A.; Sun, Z.; Dou, X.; Chen, Y. F. 2015. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine. Biotechnol Biofuels. 811

    BACKGROUND: Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production. RESULTS: We demonstrate the effectiveness of the small bioactive molecule "acetylcholine" on accumulation of biomass, total lipids, and alpha-linolenic acid in Chlorella sorokiniana. The effectiveness exists in different species of Chlorella. Moreover, the precursor and analogs of acetylcholine display increased effectiveness at higher applied doses, with maximal increases by 126, 80, and 60% over controls for biomass, total lipids, and alpha-linolenic acid, respectively. Production of calculated biodiesel was also improved by the precursor and analogs of acetylcholine. The biodiesel quality affected by changes in microalgal fatty acid composition was addressed. CONCLUSION: The chemical approach described here could improve the lipid yield and biodiesel production of photoautotrophic microalgae if combined with current genetic approaches.
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  194. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine
    Abstract

    Parsaeimehr, A.; Sun, Z. L.; Dou, X.; Chen, Y. F. 2015. Simultaneous improvement in production of microalgal biodiesel and high-value alpha-linolenic acid by a single regulator acetylcholine. Biotechnology for Biofuels. 8

    Background: Photoautotrophic microalgae are a promising avenue for sustained biodiesel production, but are compromised by low yields of biomass and lipids at present. We are developing a chemical approach to improve microalgal accumulation of feedstock lipids as well as high-value alpha-linolenic acid which in turn might provide a driving force for biodiesel production.
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  195. Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae
    Abstract

    Ma, G.; Hu, W.; Pei, H.; Jiang, L.; Ji, Y.; Mu, R. 2015. Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae. Environ Technol. 36(5-8) 622-7

    Heterogeneous KOH/Al2O3 catalysts, synthesized by the wet impregnation method with different KOH loadings (20-40 wt%) and calcination temperatures from 400 degrees C to 800 degrees C, were used to produce biodiesel from Chlorella vulgaris biomass by in situ transesterification. The highest yield of biodiesel of 89.53+/-1.58% was achieved at calcination temperature of 700 degrees C for 2 h and 35 wt% loading of KOH, and at the optimal reaction condition of 10 wt% of catalyst content, 8 mL/g of methanol to biomass ratio and at 60 degrees C for 5 h. The characteristics of the catalysts were analysed by X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller.
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  196. Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae
    Abstract

    Ma, G. X.; Hu, W. R.; Pei, H. Y.; Jiang, L. Q.; Ji, Y.; Mu, R. M. 2015. Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae. Environmental Technology. 36(5) 622-627

    Heterogeneous KOH/Al2O3 catalysts, synthesized by the wet impregnation method with different KOH loadings (20-40 wt%) and calcination temperatures from 400 degrees C to 800 degrees C, were used to produce biodiesel from Chlorella vulgaris biomass by in situ transesterification. The highest yield of biodiesel of 89.53 +/- 1.58% was achieved at calcination temperature of 700 degrees C for 2 h and 35 wt% loading of KOH, and at the optimal reaction condition of 10 wt% of catalyst content, 8mL/g of methanol to biomass ratio and at 60 degrees C for 5 h. The characteristics of the catalysts were analysed by X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller.
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  197. The Potential of Microalgal Biodiesel in Turkey
    Abstract

    Tuccar, G.; Gungor, C.; Uludamar, E.; Aydin, K. 2015. The Potential of Microalgal Biodiesel in Turkey. Energy Sources Part B-Economics Planning and Policy. 10(4) 397-403

    Turkey has limited petroleum reserves which causes the country to become a foreign dependent in respect to energy. As a result, the dependency level of Turkey on foreign fossil fuel suppliers reaches around 70%. Biodiesel, which has a more favorable combustion emission profile, relatively high flash point, and good lubrication properties, can be an effective alternative energy source. However, to provide the necessary amount of oil from agricultural products may affect food production and require a high amount of water and fertilizer. With their high oil content and high productivity rates, microalgae seems to be the best source of fuel which can replace petroleum products totally. This article introduces methods of microalgae production and discusses the potential of Turkey to pass microalgal biodiesel technology.
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  198. The Potential of Using Pulsed Electric Field (PEF) Technology as the Cell Disruption Method to Extract Lipid from Microalgae for Biodiesel Production
    Abstract

    Joannes, C.; Sipaut, C. S.; Dayou, J.; Yasir, S. M.; Mansa, R. F. 2015. The Potential of Using Pulsed Electric Field (PEF) Technology as the Cell Disruption Method to Extract Lipid from Microalgae for Biodiesel Production. International Journal of Renewable Energy Research. 5(2) 598-621

    For the past few years, there has been an explosive growth of interest in biodiesel production from algae based crops. Feedstock from microalgae is a highly promising resource and can be used as an alternative for sustainable and renewable energy since; lipid from microalgae can be converted to biodiesel. The study brief reviews of the processes related to microalgae for biodiesel production. This includes the process of microalgae cultivation, microalgae harvesting, extracting microalgae lipid and conversion of biodiesel from microalgae. Biodiesel yield is dependable on the amount of lipid extracted which is affected by the technology and method of extraction. The microalgae lipid extraction using traditional methods is primarily discussed and followed by the latest technology of microalgae cell disruption based on electroporation concept. Pulsed electric fields (PEF) Technology as the potential method to extract microalgae lipid is proposed in this work. Treatment of PEF associated with conventional extraction, such as solvent extraction is demonstrated to improve the extraction efficiency of lipid and other valuable intracellular components from microalgae. The paper also described the electroporation mechanism occurred in a cell membrane and the factors that affect the mechanism. Several of PEF chamber designs were discussed which adapted from food industries, biotechnology and engineering perspective view. The benefits and limitation of PEF in the microalgae lipid extraction are also mentioned in this work for the purpose of the future improvement of the PEF extraction system.
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  199. The production of biodiesel by algae: Integration with shrimp farming
    Abstract

    Silva, R. M. D.; Bacholsky, R. G.; Jeronimo, C. E. D. 2015. The production of biodiesel by algae: Integration with shrimp farming. Revista Eletronica Em Gestao Educacao E Tecnologia Ambiental. 19(3) 713-724

    Biodiesel production in the world and has grown steadily along its technologies. Natural resources are plentiful, however there is some difficulty in the extraction of these biomass resources, in most cases financial. One of these is the algae that even having an exponential potential for the generation of biodiesel, finds a huge bottleneck on the cost of it. There are at least four recovery mechanism biodiesel have been addressed but the two most used on the market, which consists of open ponds (Raceway Pounds) systems and bioreactors system. Applicability to both the reuse of effluents from shrimp farming. Water features were addressed in a clear and biodiesel from algae were also covered reporting of their quality and the commercial purpose as required by the National Petroleum Agency.
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  200. Thermal and chromatographic characterization of biomass, lipid material, and microalgal biodiesel from Monoraphidium sp.
    Abstract

    Gomes, A. F.; Gomes, M. P. S.; Di Souza, L.; Costa, M. 2015. Thermal and chromatographic characterization of biomass, lipid material, and microalgal biodiesel from Monoraphidium sp.. Journal of Thermal Analysis and Calorimetry. 119(3) 1861-1866

    The cultivation of microalgae for biodiesel production order emerges as an extremely promising aspect, because the culture of these vegetables microorganisms includes short breeding cycle, smaller areas for planting, and residual biomass rich in protein content. The presence of proteins in biomass and triacylglycerols (TAG) in lipid material (LM) of microalgal Monoraphidium sp. were verified by thermogravimetry (TG). The LM of the microalgae was transesterified (alkaline), the fatty profile evidenced qualitatively and quantitatively by gas chromatography (GC) and used alternatively and quantitatively by TG. The thermal results showed protein content in biomass and TAG in microalgal ML. Chromatographic (GC) data revealed high content of saturated fatty acids (approximately 70 %) being the eicosanoic acid its major constituent (33.7 %), which resulted in a high thermal stability of biodiesel. The conversion in transesterification was approximately 98 % by GC and 97 % by TG, these values being compliant.
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  201. Third generation biodiesel production from microalgae
    Abstract

    Francisco, E. C.; Franco, T. T.; Maroneze, M. M.; Zepka, L. Q.; Jacob-Lopes, E. 2015. Third generation biodiesel production from microalgae. Ciencia Rural. 45(2) 349-355

    The aim of the study was to evaluate the third generation biodiesel produced from heterotrophic cultivation of the microalgae Phormidium sp. employing cassava starch as source of organic carbon. An experimental design was performed to determine the optimal conditions of temperature and C/N ratio. From the best growing conditions, was developed cultivations in batch and fedbatch in a bioreactor and evaluated the biodiesel quality. The results indicate that the temperature of 30 degrees C and the C/N ratio of 68 are the ideal conditions of the process. The highest biomass productivity (50.41mgL(-1)h(-1)) and lipid productivity (7.49mgL(-1)h(-1)) were obtained in batch cultivations. The fatty acids most representative were caproic acid (65.29%) and oleic acid (23.88%). The fuel properties of biodiesel: ester content of 99.9%, cetane number of 54.88, iodine value of 21.47gI100g(-1), unsaturation degree of 23.88% and a cold filter plugging point of 39.21 degrees C, comply with the main international and national standards.
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  202. Two-step microalgal biodiesel production using acidic catalyst generated from pyrolysis-derived bio-char
    Abstract

    Dong, T.; Gao, D. F.; Miao, C.; Yu, X. C.; Degan, C.; Garcia-Perez, M.; Rasco, B.; Sablani, S. S.; Chen, S. L. 2015. Two-step microalgal biodiesel production using acidic catalyst generated from pyrolysis-derived bio-char. Energy Conversion and Management. 1051389-1396

    An efficient process for biodiesel production from fast-refined microalgal oil was demonstrated. A low cost catalyst prepared from pyrolysis-derived bio-char, was applied in pre-esterification to reduce free fatty acid (FFA) content. Results showed that the bio-char catalyst was highly active in esterification; however, the performance of the catalyst significantly reduced when crude microalgal oil was used as feedstock. To solve the problem caused by catalyst-fouling, a fast and scalable crude oil refinery procedure was carried out to remove chlorophyll and phospholipids that might degrade the catalyst and the quality of biodiesel. The activity and reusability of bio-char catalyst were remarkably improved in the fast-refined oil. FFA content in the refined microalgal oil was reduced to less than 0.5% after pre-esterification. The bio-char catalyst could be reused for 10 cycles without dramatic loss in activity. The pre-esterification fits the first-order kinetic reaction with activation energy of 42.16 kJ/mol. The activity of bio-char catalyst was superior to commercial Amberlyst-15 under the same reaction condition. A total fatty acid methyl ester (FAME, namely biodiesel) yield of 99% was obtained following the second-step Ca0-catalyzed transesterification. The cost-effective bio-char catalyst has great potential for biodiesel production using feedstocks having high FFA content. (C) 2015 Elsevier Ltd. All rights reserved.
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  203. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production
    Abstract

    Pradeep, V.; Van Ginkel, S. W.; Park, S.; Igou, T.; Yi, C.; Fu, H.; Johnston, R.; Snell, T.; Chen, Y. S. 2015. Use of Copper to Selectively Inhibit Brachionus calyciflorus (Predator) Growth in Chlorella kessleri (Prey) Mass Cultures for Algae Biodiesel Production. International Journal of Molecular Sciences. 16(9) 20674-20684

    A single Brachionus rotifer can consume thousands of algae cells per hour causing an algae pond to crash within days of infection. Thus, there is a great need to reduce rotifers in order for algal biofuel production to become reality. Copper can selectively inhibit rotifers in algae ponds, thereby protecting the algae crop. Differential toxicity tests were conducted to compare the copper sensitivity of a model rotiferB. calyciflorus and an alga, C. kessleri. The rotifer LC50 was <0.1 ppm while the alga was not affected up to 5 ppm Cu(II). The low pH of the rotifer stomach may make it more sensitive to copper. However, when these cultures were combined, a copper concentration of 1.5 ppm was needed to inhibit the rotifer as the alga bound the copper, decreasing its bioavailability. Copper (X ppm) had no effect on downstream fatty acid methyl ester extraction.
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  204. Utilization of biodiesel-derived glycerol or xylose for increased growth and lipid production by indigenous microalgae
    Abstract

    Leite, G. B.; Paranjape, K.; Abdelaziz, A. E. M.; Hallenbeck, P. C. 2015. Utilization of biodiesel-derived glycerol or xylose for increased growth and lipid production by indigenous microalgae. Bioresource Technology. 184123-130

    Microalgae are a promising alternative for sustainable biofuel production, but production yields and costs present a significant bottleneck. Here, the use of glycerol and xylose to boost the lipid yield was evaluated using ten strains from the Universite de Montreal collection of microalgae. This report shows that some microalgal strains are capable of mixotrophic and heterotrophic growth on xylose, the major carbon source found in wastewater streams from pulp and paper industries, with an increase in growth rate of 2.8-fold in comparison to photoautotrophic growth, reaching up to mu = 1.1/d. On glycerol, growth rates reached as high as mu = 1.52/d. Lipid productivity increased up to 370% on glycerol and 180% on xylose for the strain LB1H10, showing the suitability of this strain for further development of biofuels production through mixotrophic cultivation. (C) 2014 Elsevier Ltd. All rights reserved.
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  205. Utilization of Scenedesmus obliquus biomass as feedstock for biodiesel and other industrially important co-products: An integrated paradigm for microalgal biorefinery
    Abstract

    Patnaik, R.; Mallick, N. 2015. Utilization of Scenedesmus obliquus biomass as feedstock for biodiesel and other industrially important co-products: An integrated paradigm for microalgal biorefinery. Algal Research-Biomass Biofuels and Bioproducts. 12328-336

    With an aim to design a microalgal biorefinery taking Scenedesmus obliquus as a model organism, a detailed sequential production protocol was developed for the first time for beta-carotene, biodiesel, omega-3 fatty acids, glycerol and bioethanol from S. obliquus biomass. This research study not just projects S. obliquus as a feasible option for a microalgal biorefinery but also addresses the issue of economic and environmental sustainability by suggesting an optimized nutrient condition for maximizing benefits from themicroalgal biomass. GC-MS technique has been used for the qualitative and quantitative analysis of the biodiesel obtained, and mass spectrophotometric technique has been used for quantitative analysis of the other co-products. The detailed process developed, yielded 0.06 g of beta-carotene, 38 g of biodiesel, 2 g of omega-3 fatty acids, 3 g of glycerol and 17 g of ethanol from 100 g of S. obliquus biomass. A comparative analysis of the total light energy consumed and costs of nutrients incurred under autotrophic and mixotrophic modes has been presented. Additionally, more than twice the number of cultivation cycles per year, producing >12 fold higher biodiesel yield and >4 fold higher yield of co-products under optimized growth condition further highlights the significance of the strategy suggested. (C) 2015 Elsevier B.V. All rights reserved.
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  206. A novel biodiesel production method consisting of oil extraction and transesterification from wet microalgae
    Abstract

    Chen, C. L.; Change, J. S.; Huang, C. C.; Ho, K. C.; Hsiao, P. X.; Wu, M. S. 2014. A novel biodiesel production method consisting of oil extraction and transesterification from wet microalgae. International Conference on Applied Energy, Icae2014. 611294-1297

    Microalgae biodiesel is one of the most promising alternatives to fossil fuels. However, how to quickly and cost-effectively obtain a large quantity of oil form microalgae is always a challenge. In this study, a novel method was developed for biodiesel production. This method was composed of microwave disruption, partial water removal, oil extraction and transesterification. The wet microalgal biomass with a moisture content of about 80 wt% was used as the feedstock for biodiesel production. The results show that the moisture of the wet microalgae after microwave disruption and partial water removal decreased to nearly 50 wt%. The oil recovery in oil extraction from the pretreated microalgae was over 90%, and the conversion in transesterification was higher than 90%. Moreover, the test for the large amount of microalgae sludge (400 g) shows that this method was suitable for the use in large-scale microalgae-based biodiesel production. (C) 2014 The Authors. Published by Elsevier Ltd.
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  207. A Review on Biodiesel Production: Breeding Technologies of Microalgae Containing Rich Lipid
    Abstract

    Ma, C.; Liu, B. F.; Ren, H. Y.; Ren, N. Q. 2014. A Review on Biodiesel Production: Breeding Technologies of Microalgae Containing Rich Lipid. Mechanical Science and Engineering Iv. 472759-763

    Among different biodiesel production technologies, microalgae biodiesel production has exhibited largest potential as an substitute of fossil fuels. Microalgae are effective photosynthetic microorganisms and ideal materials for biodiesel production because they have many advantages, such as the high lipid content, fast growth rate and good adaptability. Most key factor for the industrialization of microalgae biodiesel production is selecting the microalgae with rich lipid, which determines the production cost of microalgae biodiesel. The different breeding technologies of microalgae can significantly shorten the breeding time, reduce the production cost and obtain expected strains. The prospect of microalgael application in biodiesel production was also discussed.
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  208. Algae biodiesel production under microwave irradiation with hexane as solvent
    Abstract

    Gude, V. G. G.; Martinez-Guerra, E. G. 2014. Algae biodiesel production under microwave irradiation with hexane as solvent. Abstracts of Papers of the American Chemical Society. 247

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  209. An analysis of energy consumption for algal biodiesel production: Comparing the literature with current estimates
    Abstract

    Dassey, A. J.; Hall, S. G.; Theegala, C. S. 2014. An analysis of energy consumption for algal biodiesel production: Comparing the literature with current estimates. Algal Research-Biomass Biofuels and Bioproducts. 489-95

    Algae have significant potential compared to other biomass feedstocks to supplement current transportation fossil fuel usage. To determine the acceptability of algal biodiesel as a replacement for petroleum, a life cycle analysis (LCA) with parameters of aerial productivity, culturing, CO2 mitigation, water use, nutrient loading, biomass harvesting, lipid extraction, and energy conversion was explored on algae production in Louisiana. High and low energy estimates found in several published LCAs were compared to current realistic estimates and analyses completed by the authors. Considering a system with an aerial biomass productivity of 15 g/m(2)/day and cell lipid concentration of 20%, the energy inputs exceeded the outputs from biodiesel production by 53% under the most ideal conditions. However, slight increases in biomass productivities and lipid contents are anticipated to tilt the overall energy balance more favorably. Considering the current conservative estimates (for biomass productivity and lipid content), incorporation of value added processes such as wastewater treatment and biogas production from residual biomass, could improve the sustainability of the system, allowing it to potentially achieve a 13.2% energy surplus. (C) 2014 Elsevier B.V. All rights reserved.
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  210. Application of magnesium sulfate and its nanoparticles for enhanced lipid production by mixotrophic cultivation of algae using biodiesel waste
    Abstract

    Sarma, S. J.; Das, R. K.; Brar, S. K.; Le Bihan, Y.; Buelna, G.; Verma, M.; Soccol, C. R. 2014. Application of magnesium sulfate and its nanoparticles for enhanced lipid production by mixotrophic cultivation of algae using biodiesel waste. Energy. 7816-22

    CG (Crude glycerol) is one of the major wastes of biodiesel production process. It can be used as a substrate for lipid production by algae and the produced lipid can be recycled as a feedstock for biodiesel production. In order to avoid substrate inhibition, lipid production media are prepared by diluting the CG with distilled water. However, CG contains only a small amount of Mg (57.41 +/- 18 ppm) and its concentration is further decreased to around 0.57 ppm during the dilution process. Apart from having a number of roles in algal physiology, Mg is the central atom of chlorophyll. Therefore, MgSO4 was evaluated as a Mg source to supplement the CG based media used for lipid production by Chlorella vulgaris. By supplementing the process with 1 g/L of MgSO4, nearly 185.29 +/- 4.53% improvement in lipid production has been achieved. Further, application of MgSO4 nanoparticles was found to improve the lipid production by 118.23 +/- 5.67%. Interestingly, unlike MgSO4, its nanoparticles were found to enhance the lipid production at the expense of only a small amount of glycerol. Thus, application of MgSO4 nanoparticles could be a potential strategy for enhanced lipid yield. (C) 2014 Elsevier Ltd. All rights reserved.
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  211. Autotrophic production of biodiesel from microalgae: An updated process and economic analysis
    Abstract

    Tercero, E. A. R.; Domenicali, G.; Bertucco, A. 2014. Autotrophic production of biodiesel from microalgae: An updated process and economic analysis. Energy. 76807-815

    A technical evaluation of a plant for biodiesel production from microalgae was investigated in which a novel configuration of a CPR (closed pond photobioreactor) is proposed. The entire process was simulated by Aspen Plus (R) and optimized energetically in order to obtain the best profits in energy terms.
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  212. Biodiesel production by microalgae cultivated using permeate from membrane bioreactors in continuous system
    Abstract

    Low, S. L.; Ong, S. L.; Ng, H. Y. 2014. Biodiesel production by microalgae cultivated using permeate from membrane bioreactors in continuous system. Water Science and Technology. 69(9) 1813-1819

    Microalgae in three submerged ceramic membrane photobioreactors (SCMPBRs) with different hydraulic retention times (HRTs) were fed with permeate of a submerged ceramic membrane bioreactor for a period of 3 months to investigate the lipid content and also the biodiesel quality produced at different HRTs. The lipid content, lipid productivity and fatty acid compositions for all three SCMPBRs were not significantly different at the 95% confidence level. These results suggested that insignificant change in the amount of fatty acids was observed at different HRTs that supplied varying concentration of nitrate in the medium. Among the fatty acids, palmitic acid, palmitoleic acid, oleic acid and linoleic acid were the main components, whereas stearic acid was a minor fatty acid. Since there was insignificant effect of HRT on lipid content, lipid productivity and fatty acid compositions, the optimum HRT for SCMPBRs can then be designed based on optimum nutrient removal performance and low membrane fouling propensity.
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  213. Biodiesel production from algae by using heterogeneous catalysts: A critical review
    Abstract

    Galadima, A.; Muraza, O. 2014. Biodiesel production from algae by using heterogeneous catalysts: A critical review. Energy. 7872-83

    The numerous challenges associated with declining fossil fuel reserves as energy sources, have accounted for a shift to biofuels as alternatives. However, transesterification of animal fats and edible vegetable oils using homogeneous acids and bases for biodiesel production is recently considered unsustainable by industries, particularly due to food versus fuel competition, and economic and environmental challenges associated with the feedstocks and catalyst systems, respectively. The paper therefore presents a critical review on the prospects of non-edible oil (i.e. algae oil) for biodiesel production via heterogeneous catalysis. It covers the advantages of algae oil exploitation over edible oil feedstocks, progress made in the oil extraction, available heterogeneous catalyst systems and reaction mechanisms, optimum transesterification conditions and the way forward. As the economic feasibility of biodiesel production from algae is supported by the valorization of glycerol as by-product, we have also highlighted key available heterogeneous catalysts to upgrade glycerol into more useful industrial products. (C) 2014 Elsevier Ltd. All rights reserved.
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  214. Biodiesel production from algae cultivated in winter with artificial wastewater through pH regulation by acetic acid
    Abstract

    Zhu, L. D.; Hiltunen, E.; Shu, Q.; Zhou, W. Z.; Li, Z. H.; Wang, Z. M. 2014. Biodiesel production from algae cultivated in winter with artificial wastewater through pH regulation by acetic acid. Applied Energy. 128103-110

    Algae have been considered as a promising biodiesel feedstock. One of the major factors affecting large-scale algae technology application is poor wintering cultivation performance. In this study, an integrated approach is investigated combining freshwater microalgae Chlorella zofingiensis wintering cultivation in pilot-scale photobioreactors with artificial wastewater treatment. Mixotrophic culture with the addition of acetic acid (pH-regulation group) and autotrophic culture (control group) were designed, and the characteristics of algal growth, lipid and biodiesel production, and nitrogen and phosphate removal were examined. The results showed that, by using acetic acid three times per day to regulate pH at between 6.8 and 7.2, the total nitrogen (TN) and total phosphate (TP) removal could be increased from 45.2% to 73.5% and from 92.2% to 100%, respectively. Higher biomass productivity of 66.94 mg L-1 day(-1) with specific growth rate of 0.260 day(-1) was achieved in the pH-regulation group. The lipid content was much higher when using acetic acid to regulate pH, and the relative lipid productivity reached 37.48 mg L-1 day(-1), The biodiesel yield in the pH-regulated group was 19.44% of dry weight, with 16-18 carbons as the most abundant composition for fatty acid methyl esters. The findings of the study prove that pH adjustment using acetic acid is efficient in cultivating C zofingiensis in wastewater in winter for biodiesel production and nutrient reduction. (C) 2014 Elsevier Ltd. All rights reserved.
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  215. Biodiesel Production from Algal Oil- A Simulation Study
    Abstract

    Jabbar, N. A.; Aidan, A.; Razouk, H.; Chihadih, N.; Faraghat, S.; El-Tal, Y. 2014. Biodiesel Production from Algal Oil- A Simulation Study. 2014 5th International Renewable Energy Congress (Irec).

    Process simulation using ASPEN Plus is carried out to model a two-stage alkali catalyzed transesterification reaction for converting micro algal oil to biodiesel. A 6: 1 methanol to algal oil feed ratio is assumed using NaOH as a catalyst at 60 degrees C reaction temperature, which results in almost 99 % biodiesel yield for the trans-esterification reaction. Product quality is assessed and compared with market bio-diesel and petro-diesel. It is shown that this project is technically feasible, which makes algal oil a much more competitive substitute to food-based plant oils.
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  216. Biodiesel production from freshwater algae in Qaraoun Lake in Lebanon
    Abstract

    Harb, E.; Mourtada, A. 2014. Biodiesel production from freshwater algae in Qaraoun Lake in Lebanon. 2014 International Conference on Renewable Energies for Developing Countries (REDEC). 133-138

    with the increasing demand for energy, dwindling oil reserves and global warming, the current fossil fuel based mechanical power and electricity has caused severe environmental degradation and energy shortage. Renewable, non-polluting and biodegradable energy sources must be adopted. Producing biodiesel from algae which represents the third bio-energy feedstock appears to be the most straightforward and least energy intensive method for biofuel production due to its higher biomass yields, higher productivities in diverse growths environments, fewer noxious emissions and better oil suitability for biodiesel processing. Constructing biodiesel processing plant from algae next to Qaraoun Lake using its water, could create a unique marriage between biofuel production and water treatment by using free nutrients such as phosphorous and nitrogen from water causing lake eutrophication and health problems. This paper includes a feasibility study for constructing an algae culture and biodiesel processing plant near Qaraoun Lake requiring an land area of 45000 m2. The study will be focusing on the selection of Botrycoccus braunii freshwater algae for the culture and its effectiveness for biodiesel processing.
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  217. Biodiesel production from indigenous microalgae grown in wastewater
    Abstract

    Komolafe, O.; Orta, S. B. V.; Monje-Ramirez, I.; Noguez, I. Y.; Harvey, A. P.; Ledesma, M. T. O. 2014. Biodiesel production from indigenous microalgae grown in wastewater. Bioresource Technology. 154297-304

    This paper describes a process for producing biodiesel sustainably from microalgae grown in wastewater, whilst significantly reducing the wastewater's nutrients and total coliform. Furthermore, ozone-flotation harvesting of the resultant biomass was investigated, shown to be viable, and resulted in FAMEs of greater oxidation stability.
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  218. Biodiesel production from lipids in wet microalgae with microwave irradiation and bio-crude production from algal residue through hydrothermal liquefaction
    Abstract

    Cheng, J.; Huang, R.; Yu, T.; Li, T.; Zhou, J. H.; Cen, K. F. 2014. Biodiesel production from lipids in wet microalgae with microwave irradiation and bio-crude production from algal residue through hydrothermal liquefaction. Bioresource Technology. 151415-418

    A cogeneration process of biodiesel and bio-crude was proposed to make full use of wet microalgae bio-mass. High-grade biodiesel was first produced from lipids in wet microalgae through extraction and transesterification with microwave irradiation. Then, low-grade bio-crude was produced from proteins and carbohydrates in the algal residue through hydrothermal liquefaction. The total yield (40.19%) and the total energy recovery (67.73%) of the cogenerated biodiesel and bio-crude were almost equal to those of the bio-oil obtained from raw microalgae through direct hydrothermal liquefaction. Upon microwave irradiation, proteins were partially hydrolyzed and the hydrolysates were apt for deaminization under the hydrothermal condition of the algal residue. Hence, the total remaining nitrogen (16.02%) in the cogenerated biodiesel and bio-crude was lower than that (27.06%) in the bio-oil. The cogeneration process prevented lipids and proteins from reacting to produce low-grade amides and other long-chain nitrogen compounds during the direct hydrothermal liquefaction of microalgae. (C) 2013 Elsevier Ltd. All rights reserved.
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  219. Biodiesel Production from Microalgae and a Cyanobacteria Grown in Different Qualities of Water
    Abstract

    Sacristan-de Alva, M.; Luna-Pabello, V. M.; Cadena-Martinez, E.; Alva-Martinez, A. F. 2014. Biodiesel Production from Microalgae and a Cyanobacteria Grown in Different Qualities of Water. Agrociencia. 48(3) 271-284

    The biodiesel production from photosynthetic microorganisms, is a topic of increasing research. However, the implications of nutrient removal and lipid accumulation capacity are unknown, when microorganisms grown in municipal wastewater with respect to be grown in a rich medium. In the present study the potential of two species of microalgae Chlorella vulgaris and Scenedesmus acutus and a cyanobacterium, Arthrospira maxima were evaluated to remove nutrients and accumulate lipids, useful for producing biodiesel, when growing into two wastewater qualities, raw (RWW) and treated (TWW), compared with an enriched medium (EM) with commercial fertilizer. The cultures were performed in volumes of 1 L, with photoperiods of light:dark of 12 h:12 h. With the results an ANOVA was performed and treatment means were compared with Tukey's test (p 0.05). The cultures in RWW showed: 1) the higher biomass productivity (p 0.05) with S. acutus (1.28 g L-1) and C. vulgaris (1.15 g LI, for A. maxima values were similar to RWW (0.93 g L-1) and EM (0.96 g L-1) (p >0.05), the highest rate of biomass increase corresponded to C. vulgaris (0.20 to 0.27 4:1-1) for the three culture media (p 0.001), and for S. acutus and A. maxima was between 0.06 and 0.14 d-1; 2) the higher efficiency of nutrient removal, over 60 % of phosphorus and 90 % of organic nitrogen (p 0.05) for all microorganisms; 3) higher lipid accumulation (p 0.05) for S. acutus, 28.3 %, C. vulgaris 22.4 % and A. maximum 13.8 %; 4) the higher production of biodiesel (between 109.4 and 244.6 mg L-1) for the three microorganisms.
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  220. Biodiesel production via lipase catalysed transesterification of microalgae lipids from Tetraselmis sp.
    Abstract

    Teo, C. L.; Jamaluddin, H.; Zain, N. A. M.; Idris, A. 2014. Biodiesel production via lipase catalysed transesterification of microalgae lipids from Tetraselmis sp.. Renewable Energy. 681-5

    Tetraselmis sp. is a green marine microalgae and known to produce lipids that can be transformed into biodiesel. The influence of nitrate concentration (0.00 g/L, 0.10 g/L, 0.14 g/L and 0.18 g/L) on the growth rate of Tetraselmis sp. was investigated. The marine microalgae were harvested during the exponential phase and lipid was extracted by chloroform-methanol solvent and quantified using Nile Red method. The conversion of lipid to biodiesel was performed via i) alkali-based transesteriflcation reaction which utilized sodium hydroxide (NaOH) and ii) enzyme catalysed transesterification process which utilized immobilized lipase. The fatty acid methyl esters (FAME) components were identified using gas chromatography (GC) and then compared with the FAME standard. The results revealed that 0.18 g/L nitrate concentration was the optimal for cultivation of microalgae. However, the highest lipid content was achieved in the absence of nitrate (0.0 g/L). The biodiesel yield from the lipase catalysed transesterification process was 7 folds higher compared to the alkaline based transesterification. (C) 2014 Elsevier Ltd. All rights reserved.
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  221. Chitosan and Its Derivatives Applied in Harvesting Microalgae for Biodiesel Production: An Outlook
    Abstract

    Chen, G. Y.; Zhao, L.; Qi, Y.; Cui, Y. L. 2014. Chitosan and Its Derivatives Applied in Harvesting Microalgae for Biodiesel Production: An Outlook. Journal of Nanomaterials.

    Although oil-accumulating microalgae are a promising feedstock for biodiesel production, large-scale biodiesel production is not yet economically feasible. As harvesting accounts for an important part of total production cost, mass production of microalgae biodiesel requires an efficient low-energy harvesting strategy so as to make biodiesel production economically attractive. Chitosan has emerged as a favorable flocculating agent in harvesting of microalgae. The aim of this paper is to review current research on the application of chitosan and chitosan-derived materials for harvesting microalgae. This offers a starting point for future studies able to invalidate, confirm, or complete the actual findings and to improve knowledge in this field.
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  222. Commercial-Scale Biodiesel Production from Algae
    Abstract

    Silva, C.; Soliman, E.; Cameron, G.; Fabiano, L. A.; Seider, W. D.; Dunlop, E. H.; Coaldrake, A. K. 2014. Commercial-Scale Biodiesel Production from Algae. Industrial & Engineering Chemistry Research. 53(13) 5311-5324

    This article evaluates pathways to cost-effective production of biofuels at a commercial scale. A thermodynamic cultivation model was simulated using Aspen Plus V7.3.1 and used to predict the area required for algae growth. This model was combined with the most promising commercial-scale methods to harvest algae and extract the oil. Conversion experiments were conducted using oil extracted from Nannochloropsis sauna algae, which was grown in salt water by Solix Biofuels. Glycerolysis was performed to reduce the free fatty-acid content of the oils. Transesterification was then carried out using a solid catalyst. Rate constants were regressed to adapt kinetic models to the rate data, which allowed the glycerolysis/transesterification process to be simulated using Aspen Plus V7.3.1. Cost estimates from the Aspen Process Economic Analyzer (APEA) were combined with industrial quotes and literature data. A cash flow analysis was performed for the entire carbon sequestration-to-biodiesel production train, yielding a biodiesel selling price of $4.34/gal. Finally, a sensitivity analysis was performed to examine the impact of various costing parameters on the viability of the process. These analyses show that the current bottlenecks for the large-scale production of biodiesel are cultivation techniques and extraction operations.
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  223. Comparison of autotrophic and mixotrophic cultivation of green microalgal for biodiesel production
    Abstract

    Li, Y. R.; Tsai, W. T.; Hsu, Y. C.; Xie, M. Z.; Chen, J. J. 2014. Comparison of autotrophic and mixotrophic cultivation of green microalgal for biodiesel production. 2013 International Conference on Alternative Energy in Developing Countries and Emerging Economies (2013 Aedcee). 52371-376

    The effects of autotrophic and mixotrophic growth on cell growth and lipid productivity of green microalgae Chodatella sp. were investigated. Carbon dioxide and piggery wastewater served as the carbon and nutrient sources, respectively, for autotrophic and mixotrophic growth. Appropriate doses of each source were found to be beneficial to biomass production. The cultures produced similar fatty acid compositions, which are suitable for biodiesel production. The specific growth rate, biomass production, and lipid productivity obtained with mixotrophic growth were 1.74, 14, and 5.6 times higher than those obtained with autotrophic growth, respectively. The mixotrophic cultivation simultaneously assimilated 99.7% ammonia nitrogen and 75.9% total phosphorus from piggery wastewater, which reduced the required nutrient for the culture of microalgae, thereby reducing the cost of biodiesel production.
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  224. Concurrent extraction and reaction for the production of biodiesel from wet microalgae
    Abstract

    Im, H.; Lee, H.; Park, M. S.; Yang, J. W.; Lee, J. W. 2014. Concurrent extraction and reaction for the production of biodiesel from wet microalgae. Bioresource Technology. 152534-537

    This work addresses a reliable in situ transesterification process which integrates lipid extraction from wet microalgae, and its conversion to biodiesel, with a yield higher than 90 wt.%. This process enables single-step production of biodiesel from microalgae by mixing wet microalgal cells with solvent, methanol, and acid catalyst; and then heating them in one pot. The effects of reaction parameters such as reaction temperature, wet cell weight, reaction time, and catalyst volume on the conversion yield are investigated. This simultaneous extraction and transesterification of wet microalgae may enable a significant reduction in energy consumption by eliminating the drying process of algal cells and realize the economic production of biodiesel using wet microalgae. (C) 2013 Elsevier Ltd. All rights reserved.
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  225. Current Status and Prospects of Biodiesel Production from Microalgae
    Abstract

    Wu, X. D.; Ruan, R. S.; Du, Z. Y.; Liu, Y. H. 2014. Current Status and Prospects of Biodiesel Production from Microalgae. Advances in Biofuel Production: Algae and Aquatic Plants. 1-20

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  226. Current status, issues and developments in microalgae derived biodiesel production
    Abstract

    Rashid, N.; Rehman, M. S. U.; Sadiq, M.; Mahmood, T.; Han, J. I. 2014. Current status, issues and developments in microalgae derived biodiesel production. Renewable & Sustainable Energy Reviews. 40760-778

    Excessive uses of fossil fuels and environmental degradation have forced the scientists to find alternative and clean sources of energy. Biofuels are considered as potential alternatives as they are green in nature and are sustainable energy sources. Biodiesel is one of the most commonly used biofuel due to its fuel characteristics. Several feedstocks can be used to produce biodiesel. However, in recent years, microalgae have emerged as potential biodiesel feedstocks. Microalgae offer advantages over conventional feedstocks. Microalgae have ability to fix atmospheric CO2 and convert it into sugars, which are then converted into fuel after biochemical processing. Microalgae have high growth rate and accumulate lipids up to 70% in their cell body. They demand less water and nutrients for their growth as compared to terrestrial crops. Despite these advantages, the scale-up applications of microalgae biofuels have some technical limitations. In this study, we have reviewed the overall process of biofuels production from microalgae with a particular emphasis on biodiesel. Critical factors affecting the biodiesel production process including species isolation, species selection, cultivation, harvesting, and oil extraction are discussed. Current research, barriers and developments concerned to each step of biodiesel production process are summarized. New ideas are proposed to improve the growth rate, lipid contents and harvesting efficiency of microalgae. To assess the economic viability of microalgae oil, an economical analysis is presented. Future research trends are also discussed. (C) 2014 Elsevier Ltd. All rights reserved.
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  227. Design of an optimal process for enhanced production of bioethanol and biodiesel from algae oil via glycerol fermentation
    Abstract

    Martin, M.; Grossmann, I. E. 2014. Design of an optimal process for enhanced production of bioethanol and biodiesel from algae oil via glycerol fermentation. Applied Energy. 135108-114

    In this paper, we optimize a process that integrates the use of glycerol to produce ethanol via fermentation within the simultaneous production of biodiesel and bioethanol from algae. The process consists of growing the algae, determining the optimal fraction of oil vs. starch, followed by oil extraction, starch liquefaction and saccharification, to sugars, oil transesterification, for which we consider two transesterification technologies (enzymes and alkali) and the fermentation of sugars and glycerol. The advantage of this process is that the dehydration technologies are common for the products of the glucose and glycerol fermentation. Simultaneous optimization and heat integration is performed using Duran and Grossmann's model. The fermentation of glycerol to ethanol increases the production of bioethanol by at least 50%. The energy and water consumptions are competitive with other processes that either sell the glycerol or use it to obtain methanol. However, the price for the biofuels is only competitive if glycerol cannot be sold to the market. (C) 2014 Elsevier Ltd. All rights reserved.
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  228. Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production
    Abstract

    Santos, C. A.; Nobre, B.; da Silva, T. L.; Pinheiro, H. M.; Reis, A. 2014. Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production. Journal of Biotechnology. 18474-83

    Chlorella protothecoides, a lipid-producing microalga, was grown heterotrophically and autotrophically in separate reactors, the off-gases exiting the former being used to aerate the latter.
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  229. Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production
    Abstract

    Santos, C. A.; Nobre, B.; Lopes da Silva, T.; Pinheiro, H. M.; Reis, A. 2014. Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production. J Biotechnol. 18474-83

    Chlorella protothecoides, a lipid-producing microalga, was grown heterotrophically and autotrophically in separate reactors, the off-gases exiting the former being used to aerate the latter. Autotrophic biomass productivity with the two-reactor association, 0.0249gL(-1)h(-1), was 2.2-fold the value obtained in a control autotrophic culture, aerated with ambient air. Fatty acid productivity was 1.7-fold the control value. C. protothecoides heterotrophic biomass productivity was 0.229gL(-1)h(-1). This biomass' fatty acid content was 34.5% (w/w) with a profile suitable for biodiesel production, according to European Standards. The carbon dioxide fixed by the autotrophic biomass was 45mgCO2L(-1)h(-1) in the symbiotic arrangement, 2.1 times the control reactor value. The avoided CO2 atmospheric emission represented 30% of the CO2 produced in the heterotrophic stage, while the released O2 represented 49% of the oxygen demand in that stage. Thus, an increased efficiency in the glucose carbon source use and a higher environmental sustainability were achieved in microalgal biodiesel production using the proposed assembly.
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  230. Economic assessment of microbial lipids for biodiesel production: Competitiveness with microalgae and agricultural plant oils
    Abstract

    Chang, H. N.; Park, G. W. 2014. Economic assessment of microbial lipids for biodiesel production: Competitiveness with microalgae and agricultural plant oils. New Biotechnology. 31S27-S27

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  231. Economic biodiesel production using algal residue as substrate of lipid producing yeast Cryptococcus curvatus
    Abstract

    Seo, Y. H.; Han, S.; Han, J. I. 2014. Economic biodiesel production using algal residue as substrate of lipid producing yeast Cryptococcus curvatus. Renewable Energy. 69473-478

    Oleaginous microbes which are surely one sustainable way of producing lipid in absolute need of reducing the substrate cost for the commercialization. In this study, algal biomass residue, which is a waste generated after the production of algae-based biofuel, was investigated for its possibility as a cheap feedstock using our newly isolated yeast Cryptococcus curvatus. To make the algae biomass bioavailable, hydrodynamic cavitation (HC) was employed as a pretreatment means, whose optimal treatment condition was systematically set up using Response Surface Methodology (RSM). The optimal condition was HC pretreatment time of 6.88 min at pH 9.47. When used the pretreated microalgae, the C curvatus can grow with growth rate of 0.584/h, biomass reached to 7.47 g/L in a day, and lipid productivity (1.5 g/L/d) was better than defined medium using commercial chemicals. (C) 2014 Elsevier Ltd. All rights reserved.
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  232. Economic feasibility of algal biodiesel under alternative public policies
    Abstract

    Amanor-Boadu, V.; Pfromm, P. H.; Nelson, R. 2014. Economic feasibility of algal biodiesel under alternative public policies. Renewable Energy. 67136-142

    The motivation for this research was to determine the influence of public policies on economic feasibility of producing algal biodiesel in a system that produced all its energy needs internally. To achieve this, a steady-state mass balance/unit operation system was modeled first. Open raceway technology was assumed for the production of algal feedstock, and the residual biomass after oil extraction was assumed fermented to produce ethanol for the transesterification process. The project assumed the production of 50 million gallons of biodiesel per year and using about 14% of the diesel output to supplement internal energy requirements. It sold the remainder biodiesel and ethanol as pure biofuels to maximize the rents from the renewable fuel standards quota system. Assuming a peak daily yield of 500 kg algal biomass (dry basis)/ha, the results show that production of algal biodiesel under the foregoing constraints is only economically feasible with direct and indirect public policy intervention. For example, the renewable fuel standards' tracking RIN (Renewable fuel Identification Number) system provides a treasury-neutral value for biofuel producers as does the reinstatement of the renewable fuel tax credit. Additionally, the capital costs of an integrated system are such that some form of capital cost grant from the government would support the economic feasibility of the algal biodiesel production. (C) 2014 Elsevier Ltd. All rights reserved.
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  233. Effect of centrifugation on water recycling and algal growth to enable algae biodiesel production
    Abstract

    Igou, T.; Van Ginkel, S. W.; Penalver-Argueso, P.; Fu, H.; Doi, S.; Narode, A.; Cheruvu, S.; Zhang, Q.; Hassan, F.; Woodruff, F.; Chen, Y. 2014. Effect of centrifugation on water recycling and algal growth to enable algae biodiesel production. Water Environ Res. 86(12) 2325-9

    The latest research shows that algal biofuels, at the production levels mandated in the Energy Independence and Security Act of 2007, will place significant demands on water and compete with agriculture meant for food production. Thus, there is a great need to recycle water while producing algal biofuels. This study shows that when using a synthetic medium, soluble algal products, bacteria, and other inhibitors can be removed by centrifugation and enable water recycling. Average water recovery reached 84% and water could be recycled at least 10 times without reducing algal growth.
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  234. Effect of Centrifugation on Water Recycling and Algal Growth to Enable Algae Biodiesel Production
    Abstract

    Igou, T.; Van Ginkel, S. W.; Penalver-Argueso, P.; Fu, H.; Doi, S.; Narode, A.; Cheruvu, S.; Zhang, Q.; Hassan, F.; Woodruff, F.; Chen, Y. S. 2014. Effect of Centrifugation on Water Recycling and Algal Growth to Enable Algae Biodiesel Production. Water Environment Research. 86(12) 2325-2329

    The latest research shows that algal biofuels, at the production levels mandated in the Energy Independence and Security Act of 2007, will place significant demands on water and compete with agriculture meant for food production. Thus, there is a great need to recycle water while producing algal biofuels. This study shows that when using a synthetic medium, soluble algal products, bacteria, and other inhibitors can be removed by centrifugation and enable water recycling. Average water recovery reached 84% and water could be recycled at least 10 times without reducing algal growth.
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  235. Effect of moisture on in situ transesterification of microalgae for biodiesel production
    Abstract

    Sathish, A.; Smith, B. R.; Sims, R. C. 2014. Effect of moisture on in situ transesterification of microalgae for biodiesel production. Journal of Chemical Technology and Biotechnology. 89(1) 137-142

    BackgroundA major hurdle with algal biodiesel production has been the energy required to dry algal biomass prior to lipid extraction and/or conversion. Water interferes with the extraction and/or conversion of algal lipids to biodiesel. The focus of this study was to evaluate the efficiency of the in situ transesterification method for biodiesel recovery when processing algal biomass with varying amounts of moisture and to evaluate changes in efficiency as in situ transesterification reaction parameters were varied.
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  236. Effective extraction of microalgae lipids from wet biomass for biodiesel production
    Abstract

    Taher, H.; Al-Zuhair, S.; Al-Marzouqi, A. H.; Haik, Y.; Farid, M. 2014. Effective extraction of microalgae lipids from wet biomass for biodiesel production. Biomass & Bioenergy. 66159-167

    Producing biodiesel from lipid extracted from microalgae is a promising approach for sustainable fuel production. However, this approach is not yet commercialized due to the high costs of upstream processes that are associated with the time consuming and/or energy intensive drying, and lipid extraction processes. In this study, the possibility of avoiding the drying process, and extracting the lipid directly from the wet concentrated cells, using enzymatic disruption to enhance the extraction, has been tested. Results showed that lysozyme and cellulase were both efficient in disrupting cell walls and enhancing lipid extraction from wet samples, with highest lipid extraction yield of 16.6% achieved using lysozyme. The applicability of using supercritical CO2 (SC-CO2) in extracting lipid from wet biomass was also tested and the highest yield of 12.5% was achieved using lysozyme. In addition, a two-step culturing process was applied, using Scenedesmus sp., to combine both high biomass growth and lipid content. The strain was able to increase its biomass productivity in the first stage, reaching 174 mg l(-1) d(-1), with almost constant lipid content. In the second stage, the lipid content was enhanced by six-fold after three weeks of nitrogen starvation, but with lower biomass productivity. (C) 2014 Elsevier Ltd. All rights reserved.
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  237. Effects of co-products on the life-cycle impacts of microalgal biodiesel
    Abstract

    Soratana, K.; Barr, W. J.; Landis, A. E. 2014. Effects of co-products on the life-cycle impacts of microalgal biodiesel. Bioresource Technology. 159157-166

    Microalgal biodiesel production has been investigated for decades, yet it is not commercially available. Part of the problem is that the production process is energy and chemical intensive due, in part, to the high portion of microalgal biomass left as residues. This study investigated cradle-to-gate life-cycle environmental impacts from six different scenarios of microalgal biodiesel and its co-products. Ozone depletion, global warming, photochemical smog formation, acidification and eutrophication potentials were assessed using the Tool for the Reduction and Assessment of Chemical and other environmental Impacts (TRACI). Monte Carlo Analysis was conducted to investigate the processes with major contribution in each impact category. The market opportunity for each co-product was examined based on supply, demand and prices of the products that could potentially be substituted by the co-products. The results indicated that the scenario with the least life-cycle environmental impacts in all the five impact categories with the highest net energy ratio was the scenario utilizing a multitude of co-products including bioethanol from lipid-extracted microalgae (LEA), biomethane (to produce electricity and heat) from simultaneous saccharification-fermentation (SSF) residues, land-applied material from SSF residue anaerobic digestion (AD) solid digestate, recycling nutrients from SSF residue AD liquid digestate and CO2 recovered from SSF process contributed. Decreasing the energy consumption of the centrifuge in the land-applied material production process and increasing the lipid content of microalgae can reduce environmental footprints of the co-products. The same scenario also had the highest total income indicating their potential as co-products in the market. (C) 2014 Elsevier Ltd. All rights reserved.
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  238. Efficacy of drying and cell disruption techniques on lipid recovery from microalgae for biodiesel production
    Abstract

    Guldhe, A.; Singh, B.; Rawat, I.; Ramluckan, K.; Bux, F. 2014. Efficacy of drying and cell disruption techniques on lipid recovery from microalgae for biodiesel production. Fuel. 12846-52

    Downstream processing of microalgal biomass presents a significant challenge to large scale biodiesel production. Scenedesmus sp. which is known to be a potential feedstock for biodiesel production was cultivated in an open circular pond. The biomass productivity peaked at day 21 with a yield of 1.16 g L-1. Biomass was harvested by gravitational settling followed by centrifugation. Harvested biomass was dried using the freeze drying, oven drying and sun drying processes followed by lipid extraction which yielded 29.65%, 28.63% and 28.33% lipid g(-1) DCW (dry cell weight) respectively. Lipids were extracted from microalgal biomass dried by selected drying techniques using microwave and sonication for cell disruption in the presence of mixture of chloroform and ethanol ( 1: 1). Microwave assisted extraction of sun dried biomass yielded 28.33% lipid g(-1) DCW, as compared to 18.9% lipid g(-1) DCW achieved by sonication assisted extraction. The saponification and acid values of the lipid obtained from Scenedesmus sp. dried by selected drying techniques showed high saponification and acid value indicating presence of high free fatty acid content. Effect of different drying and cell disruption technique on fatty acid profile of lipids extracted from Scenedesmus sp. biomass was also studied. These values indicate promising potential of the oil produced for conversion into biodiesel. (C) 2014 Elsevier Ltd. All rights reserved.
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  239. Electrochemical harvesting process for microalgae by using nonsacrificial carbon electrode: A sustainable approach for biodiesel production
    Abstract

    Misra, R.; Guldhe, A.; Singh, P.; Rawat, I.; Bux, F. 2014. Electrochemical harvesting process for microalgae by using nonsacrificial carbon electrode: A sustainable approach for biodiesel production. Chemical Engineering Journal. 255327-333

    Microalgal biodiesel has to overcome a cost incurring harvesting bottleneck for its commercial scale production. In this study electrochemical harvesting (ECH) using Chlorella sorokiniana and Scenedesmus obliquus was investigated. Nonsacrificial carbon electrodes were used to overcome the cost and metallic contamination implications. The effect of applied current and addition of electrolyte on harvesting efficiency was investigated. Addition of electrolyte (NaCl) increased the recovery efficiency of C. sorokiniana from 65.99% to 94.52%. ECH process has not shown any deteriorating effect on the lipid extraction process as well as fatty acid composition. ECH process for C sorokiniana with optimum conditions showed 94.52% recovery efficiency with energy consumption of 1.6 kWh kg(-1). This study for the first time validates application of nonsacrificial carbon electrodes in ECH process of microalgae. Attractive high recovery efficiency, low energy consumption and use of nonsacrificial electrodes could make ECH a possible step in commercial microalgal biomass and biodiesel production. (C) 2014 Elsevier B.V. All rights reserved.
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  240. Enhancement of the microalgal growth and fatty acid content under the influence of phytohormones for biodiesel production
    Abstract

    Salama, E.; Kabra, A. N.; Abdlkader, M. M. A.; Jeon, B. H. 2014. Enhancement of the microalgal growth and fatty acid content under the influence of phytohormones for biodiesel production. Abstracts of Papers of the American Chemical Society. 248

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  241. Enhancing growth and lipid production of marine microalgae for biodiesel production via the use of different LED wavelengths
    Abstract

    Teo, C. L.; Atta, M.; Bukhari, A.; Taisir, M.; Yusuf, A. M.; Idris, A. 2014. Enhancing growth and lipid production of marine microalgae for biodiesel production via the use of different LED wavelengths. Bioresource Technology. 16238-44

    Wavelength of light is a crucial factor which renders microalgae as the potential biodiesel. In this study, Tetraselmis sp. and Nannochloropsis sp. as famous targets were selected. The effect of different light wavelengths on growth rate and lipid production was studied. Microalgae were cultivated for 14 days as under blue, red, red-blue LED and white fluorescent light. The growth rate of microalgae was analyzed by spectrophotometer and cell counting while oil production under improved Nile red method. Optical density result showed the microalgae exhibited better growth curve under blue wavelength. Besides, Tetraselmis sp. and Nannochloropsis sp. under blue wavelength showed the higher growth rate (1.47 and 1.64 day(-1)) and oil production (102.954 and 702.366 a.u.). Gas chromatography analysis also showed that palmitic acid and stearic acid which were compulsory components for biodiesel contribute around 49-51% of total FAME from Nannochloropsis sp. and 81-83% of total FAME from Tetraselmis sp. (C) 2014 Elsevier Ltd. All rights reserved.
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  242. Enhancing the various solvent extraction method via microwave irradiation for extraction of lipids from marine microalgae in biodiesel production
    Abstract

    Teo, C. L.; Idris, A. 2014. Enhancing the various solvent extraction method via microwave irradiation for extraction of lipids from marine microalgae in biodiesel production. Bioresource Technology. 171477-481

    The types of microalgae strains and the method used in lipid extraction have become crucial factors which influence the productivity of crude oil. In this paper, Nannochloropsis sp. and Tetraselmis sp. were chosen as the strains and four different methods were used to extract the lipids: Hara and Radin, Folch, Chen and Bligh and Dyer. These methods were performed by using conventional heating and microwave irradiation methods. Results revealed that highest lipid yield from the different species was obtained using different extraction methods; both under microwave irradiation. The lipid yield for Tetraselmis sp. and Nannochloropsis sp. was highest when Hara and Radin (8.19%), and Folch (8.47%) methods were used respectively under microwave irradiation. The lipids extracted were then transesterified to biodiesel and the quality of the biodiesel was analyzed using the gas chromatography. (C) 2014 Elsevier Ltd. All rights reserved.
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  243. Environmental Factors Influencing Algal Biodiesel Production
    Abstract

    Chavan, K. J.; Chouhan, S.; Jain, S.; Singh, P.; Yadav, M.; Tiwari, A. 2014. Environmental Factors Influencing Algal Biodiesel Production. Environmental Engineering Science. 31(11) 602-611

    Biodiesel has received much attention in recent years. Due to significant lipid and carbohydrate production and the ability to grow using nonpotable water sources, microalgae are being scrutinized as a potential high-yield feedstock for biofuel production. For biodiesel production, selection of suitable strain of microalgae depends on various factors, such as lipid productivity, percentage of lipids, biomass productivity, CO2 tolerance, and nutrient requirements. In both natural and engineered systems, microalgae can be exposed to a variety of environmental conditions that have an effect on cellular composition and growth rate. Furthermore, the amount of carbon fixed in lipids and carbohydrates is highly influenced by nutrient availability and environmental factors. This article reviews the potential of microalgae for lipid production and effects of environmental factors (e.g., light, temperature, and pH) and nutrient availability (e.g., nitrogen, carbon, phosphorus, and trace metals).
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  244. Enzymatic biodiesel production of microalgae lipids under supercritical carbon dioxide: Process optimization and integration
    Abstract

    Taher, H.; Al-Zuhair, S.; Al-Marzouqi, A. H.; Haik, Y.; Farid, M. 2014. Enzymatic biodiesel production of microalgae lipids under supercritical carbon dioxide: Process optimization and integration. Biochemical Engineering Journal. 90103-113

    Enzymatic biodiesel production in supercritical CO2 (SC-CO2) has recently received an increasing attention, as an alternative to the conventional chemical processes. In this study, enzymatic production of biodiesel from microalgal lipids was investigated in batch and integrated extraction-reaction systems. In the batch system, the effect of enzyme loading (15-50 wt%), temperature (35-55 degrees C) and methanol to lipid molar ratios (3-15:1) were studied, and response surface methodology was employed to optimize selected factors effect. The optimum transesterification yield of 80% was obtained at 47 degrees C, 200 bar, 35% enzyme loading, and 9:1 molar ratio after 4 h reaction in the batch system. The experimental results were also used to determine the kinetics parameters of the Ping-Pong Bi Bi model, with methanol inhibition, suggested to describe the reaction.
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  245. Evaluation of Algal Biomass and Biodiesel Co-Products for Bioenergy Applications
    Abstract

    Nicol, R. W.; Lamers, A.; Lubitz, W. D.; McGinn, P. J. 2014. Evaluation of Algal Biomass and Biodiesel Co-Products for Bioenergy Applications. Journal of Biobased Materials and Bioenergy. 8(4) 429-436

    Several forms of energy, such as hydrogen gas, butanol, biogas, and ethanol can be produced from renewable, biological resources. However, many bioenergy technologies are currently at the lab scale and the list of commercial operations successfully producing bioenergy in Canada is much shorter. Currently, Canada's bioenergy production is dominated by biofuels such as ethanol and biodiesel, biomass for combustion and the use of anaerobic digesters for biogas production. Bioenergy production in Canada is relatively new, especially in comparison to other renewable energy technologies like hydroelectricity, and therefore opportunities exist to improve bioenergy's economic and environmental impact. One route for improvement is through the valorization of co-products, and our efforts to use fungi to convert biodiesel wastewater and biodiesel derived crude glycerol to the value-added product single cell oil is reviewed. Wastewater is generated during biodiesel production through water washing of the unfinished biodiesel, and COD values for biodiesel wastewater are reported to range from approximately 31,000 to 590,000 mg L-1. Glycerol is generated in biodiesel production during the tranesterification reaction of intact triacylglycerol molecules with an alcohol and a strong base. This glycerol is a crude co-product, and can contain high levels of methanol, residual oils and water. Cultivation of the newly described oleaginous fungus Galactomyces geotrichum in 50 g L-1 crude glycerol, 10 g L-1 casein and 200 mL L-1 biodiesel wastewater yielded fungal biomass with an average single cell oil content of 51.1%. We also review our data on the use of microalga Nannochloropsis granulata as a feedstock for anaerobic digestion. This work was completed in a 2.2 m(3) pilot anaerobic digester and is unique as it is much larger in scope than the vast majority of literature sources reporting on the use of algae in anaerobic digestion applications. The use of N. granulata as a co-digestion substrate with swine manure reduced the methane yield as compared to swine manure alone. Algal biomass added at 0.5 kg volatile solids per day, 1.1 kg volatile solids per day and 1.6 kg volatile solids per day reduced methane yield by 48.4%, 55.9% and 64.7% respectively. The observed reductions may have been due to inhibitory metabolites produced during algal digestion or because of recalcitrance of the algal cell wall. The digester inoculum was not pre-adapted to microalgae degradation and this may have also played a role. Use of algal biomass as a feedstock for anaerobic digestion is still in its infancy, and biomass pre-treatments, different algal strains or different digestion techniques could be needed for the successful utilization of algae. Microalgae have other positive attributes including the ability to remediate waste streams and recycle nutrients as well act as a single source for multiple products and more research is needed in order to successfully exploit this versatile feedstock.
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  246. Evaluation of Different Operational Strategies for Biodiesel Production by Direct Transesterification of Microalgal Biomass
    Abstract

    Hidalgo, P.; Toro, C.; Ciudad, G.; Schober, S.; Mittelbach, M.; Navia, R. 2014. Evaluation of Different Operational Strategies for Biodiesel Production by Direct Transesterification of Microalgal Biomass. Energy & Fuels. 28(6) 3814-3820

    In this study, different operational strategies for biodiesel production by direct transesterification of microalgal biomass (Botryococcus braunii) were evaluated. These operational strategies include the use of different acyl acceptors and the application of different catalysts and solvent mixtures. All these strategies were performed in two reaction systems: a conventional batch reactor (CBR) and a reflux extraction reactor (RER). The highest biodiesel production yields (80.6 wt %) were obtained in the RER using methanol as acyl acceptor and H2SO4 as catalyst. On the opposite, the lowest biodiesel production yield (64.5 wt %) was observed in the CBR system. Moreover, when a low proportion of cosolvent (i.e 3:1 v/v solvent/cosolvent) was incorporated in the reaction, an increase in biodiesel production yields was observed. A higher cosolvent content in the reaction mixture provoked however a diminishment in FAAE (fatty acid alkyl esters) yield in both systems, due to a drastically reduction of alcohol-lipids molar ratio.
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  247. Evaluation of indigenous microalgal isolate Chlorella sp FC2 IITG as a cell factory for biodiesel production and scale up in outdoor conditions
    Abstract

    Muthuraj, M.; Kumar, V.; Palabhanvi, B.; Das, D. 2014. Evaluation of indigenous microalgal isolate Chlorella sp FC2 IITG as a cell factory for biodiesel production and scale up in outdoor conditions. Journal of Industrial Microbiology & Biotechnology. 41(3) 499-511

    The present study reports evaluation of an indigenous microalgal isolate Chlorella sp. FC2 IITG as a potential candidate for biodiesel production. Characterization of the strain was performed under photoautotrophic, heterotrophic, and mixotrophic cultivation conditions. Further, an open-pond cultivation of the strain under outdoor conditions was demonstrated to evaluate growth performance and lipid productivity under fluctuating environmental parameters and in the presence of potential contaminants. The key findings were: (1) the difference in cultivation conditions resulted in significant variation in the biomass productivity (73-114 mg l(-1) day(-1)) and total lipid productivity (35.02-50.42 mg l(-1) day(-1)) of the strain; (2) nitrate and phosphate starvation were found to be the triggers for lipid accumulation in the cell mass; (3) open-pond cultivation of the strain under outdoor conditions resulted in biomass productivity of 44 mg l(-1) day(-1) and total lipid productivity of 10.7 mg l(-1) day(-1); (4) a maximum detectable bacterial contamination of 7 % of the total number of cells was recorded in an open-pond system; and (5) fatty acid profiling revealed abundance of palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2), which are considered to be the key elements for suitable quality biodiesel.
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  248. Extraction of saponifiable lipids from wet microalgal biomass for biodiesel production
    Abstract

    Callejon, M. J. J.; Medina, A. R.; Sanchez, M. D. M.; Pena, E. H.; Cerdan, L. E.; Moreno, P. A. G.; Grima, E. M. 2014. Extraction of saponifiable lipids from wet microalgal biomass for biodiesel production. Bioresource Technology. 169198-205

    Saponifiable lipids (SLs) were extracted with hexane from wet biomass (86 wt% water) of the microalga Nannochloropsis gaditana in order to transform them into fatty acid methyl esters (FAMEs, biodiesel). The influence of homogenization pressure on SL extraction yield at low temperature (20-22 degrees C) was studied. Homogenization at 1700 bar tripled the SL extraction yield. Two biomass batches with similar total lipid content but different lipidic compositions were used. Batch 1 contained fewer SLs (12.0 wt%) and neutral saponifiable lipids (NSLs, 7.9 wt%) than batch 2 (21.6 and 17.2 wt%, respectively). For this reason, and due to the selectivity of hexane toward NSLs, high SL yield (69.1 wt%) and purity (71.0 wt%) were obtained from batch 2. Moreover, this extract contains a small percentage of polyunsaturated fatty acids (16.9 wt%), thereby improving the biodiesel quality. Finally, up to 97.0% of extracted SLs were transformed to FAMEs by acid catalyzed transesterification. (C) 2014 Elsevier Ltd. All rights reserved.
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  249. Highly-efficient enzymatic conversion of crude algal oils into biodiesel
    Abstract

    Wang, Y.; Liu, J.; Gerken, H.; Zhang, C. W.; Hu, Q.; Li, Y. T. 2014. Highly-efficient enzymatic conversion of crude algal oils into biodiesel. Bioresource Technology. 172143-149

    Energy-intensive chemical conversion of crude algal oils into biodiesel is a major barrier for cost-effective algal biofuel production. To overcome this problem, we developed an enzyme-based platform for conversion of crude algal oils into fatty acid methyl esters. Crude algal oils were extracted from the oleaginous microalga Nannochloropsis oceanica IMET1 and converted by an immobilized lipase from Candida antarctica. The effects of different acyl acceptors, t-butanol as a co-solvent, oil to t-butanol ratio, oil to methanol ratio, temperature and reaction time on biodiesel conversion efficiency were studied. The conversion efficiency reached 99.1% when the conversion conditions were optimized, i.e., an oil to t-butanol weight ratio of 1:1, an oil to methanol molar ratio of 1:12, and a reaction time of 4 h at 25 degrees C. The enzymatic conversion process developed in this study may hold a promise for low energy consumption, low wastewater-discharge biochemical conversion of algal feedstocks into biofuels. Published by Elsevier Ltd.
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  250. Improved production of a recombinant Rhizomucor miehei lipase expressed in Pichia pastoris and its application for conversion of microalgae oil to biodiesel
    Abstract

    Huang, J.; Xia, J.; Yang, Z.; Guan, F.; Cui, D.; Guan, G.; Jiang, W.; Li, Y. 2014. Improved production of a recombinant Rhizomucor miehei lipase expressed in Pichia pastoris and its application for conversion of microalgae oil to biodiesel. Biotechnol Biofuels. 7111

    BACKGROUND: We previously cloned a 1,3-specific lipase gene from the fungus Rhizomucor miehei and expressed it in methylotrophic yeast Pichia pastoris strain GS115. The enzyme produced (termed RML) was able to catalyze methanolysis of soybean oil and showed strong position specificity. However, the enzyme activity and amount of enzyme produced were not adequate for industrial application. Our goal in the present study was to improve the enzyme properties of RML in order to apply it for the conversion of microalgae oil to biofuel. RESULTS: Several new expression plasmids were constructed by adding the propeptide of the target gene, optimizing the signal peptide, and varying the number of target gene copies. Each plasmid was transformed separately into P. pastoris strain X-33. Screening by flask culture showed maximal (21.4-fold increased) enzyme activity for the recombinant strain with two copies of the target gene; the enzyme was termed Lipase GH2. The expressed protein with the propeptide (pRML) was a stable glycosylated protein, because of glycosylation sites in the propeptide. Quantitative real-time RT-PCR analysis revealed two major reasons for the increase in enzyme activity: (1) the modified recombinant expression system gave an increased transcription level of the target gene (rml), and (2) the enzyme was suitable for expression in host cells without causing endoplasmic reticulum (ER) stress. The modified enzyme had improved thermostability and methanol or ethanol tolerance, and was applicable directly as free lipase (fermentation supernatant) in the catalytic esterification and transesterification reaction. After reaction for 24 hours at 30 degrees C, the conversion rate of microalgae oil to biofuel was above 90%. CONCLUSIONS: Our experimental results show that signal peptide optimization in the expression plasmid, addition of the gene propeptide, and proper gene dosage significantly increased RML expression level and enhanced the enzymatic properties. The target enzyme was the major component of fermentation supernatant and was stable for over six months at 4 degrees C. The modified free lipase is potentially applicable for industrial-scale conversion of microalgae oil to biodiesel.
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  251. Improved production of a recombinant Rhizomucor miehei lipase expressed in Pichia pastoris and its application for conversion of microalgae oil to biodiesel
    Abstract

    Huang, J. J.; Xia, J.; Yang, Z.; Guan, F. F.; Cui, D.; Guan, G. H.; Jiang, W.; Li, Y. 2014. Improved production of a recombinant Rhizomucor miehei lipase expressed in Pichia pastoris and its application for conversion of microalgae oil to biodiesel. Biotechnology for Biofuels. 7

    Background: We previously cloned a 1,3-specific lipase gene from the fungus Rhizomucor miehei and expressed it in methylotrophic yeast Pichia pastoris strain GS115. The enzyme produced (termed RML) was able to catalyze methanolysis of soybean oil and showed strong position specificity. However, the enzyme activity and amount of enzyme produced were not adequate for industrial application. Our goal in the present study was to improve the enzyme properties of RML in order to apply it for the conversion of microalgae oil to biofuel.
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  252. Integrating Glycerol to Methanol vs. Glycerol to Ethanol within the Production of Biodiesel from Algae
    Abstract

    Martin, M.; Grossmann, I. 2014. Integrating Glycerol to Methanol vs. Glycerol to Ethanol within the Production of Biodiesel from Algae. 24th European Symposium on Computer Aided Process Engineering, Pts a and B. 3385-90

    In this work, we use a superstrucutre optimization approach for the comparison between traditional biodiesel plants and the integration of glycerol to methanol production or its use to obtain ethanol within the production of biodiesel from algae. In the first case the glycerol is reformed, either autoreforming or steam reforming, the raw syngas purified and whose composition (H-2:CO ratio) is adjusted for the production of methanol. The methanol once purified is used for the transesterification of the oil produced from the algae. In the second case we take advantage of the fact that the algae composition allows the simultaneous production of ethanol and biodiesel. The starch is liquified and saccharified to obtain glucose that is fermented to ethanol. On the other hand, the oil is transesterified with ethanol to produce biodiesel, either using an enzymatic or an homogeneous catalysts. The glycerol is fermented to ethanol. Both water-ethanol, streams from glucose and from glycerol are fed to a multieffect column and later to a molecular sieve. The dehydrated ethanol is used for the transesterification of the oil while the excess is sold as biofuel. Glycerol as byproduct is still interesting as long as its price is over $0.05 /kg. In terms of integrated facilities, the use of glycerol to produce ethanol requires almost twice the investment, but the production cost is a fourth lower with an increased production of biofuels by 50 %.
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  253. Isolation and characterization of microalgae for biodiesel production from Nisargruna biogas plant effluent
    Abstract

    Tal, M.; Ghosh, S.; Kapadnis, B.; Kale, S. 2014. Isolation and characterization of microalgae for biodiesel production from Nisargruna biogas plant effluent. Bioresource Technology. 169328-335

    Increasing energy demand and depleting fossil fuel sources have intensified the focus on biofuel production. Microalgae have emerged as a desirable source for biofuel production because of high biomass and lipid production from waste water source. In this study, five microalgae were isolated from effluents of Nisargruna biogas plants. These isolates were identified based on morphology and partial 18S and 23S rRNA gene sequences. Growth and lipid accumulation potential of these microalgae were investigated. One isolate, Chlorella sp. KMN3, accumulated high biomass (1.59 +/- 0.05 g L-1) with moderate lipid content (20%), while another isolate Monoraphidium sp. KMN5 showed moderate biomass accumulation of 0.65 +/- 0.05 g L-1 with a very high (35%) lipid content. The fatty acid methyl esters mainly composed of C-16:0, C-18:0, C-18:1 and C-18:2. This observation makes these microalgae immensely potential candidate for biodiesel production using the effluent of a biogas plant as feed stock. (C) 2014 Elsevier Ltd. All rights reserved.
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  254. Isolation of Novel Microalgae from Acid Mine Drainage and Its Potential Application for Biodiesel Production
    Abstract

    Yun, H. S.; Lee, H.; Park, Y. T.; Ji, M. K.; Kabra, A. N.; Jeon, C.; Jeon, B. H.; Choi, J. 2014. Isolation of Novel Microalgae from Acid Mine Drainage and Its Potential Application for Biodiesel Production. Applied Biochemistry and Biotechnology. 173(8) 2054-2064

    Microalgae were selected and isolated from acid mine drainage in order to find microalgae species which could be cultivated in low pH condition. In the present investigation, 30 microalgae were isolated from ten locations of acid mine drainage in South Korea. Four microalgae were selected based on their growth rate, morphology, and identified as strains of KGE1, KGE3, KGE4, and KGE7. The dry biomass of microalgae species ranged between 1 and 2 g L-1 after 21 days of cultivation. The growth kinetics of microalgae was well described by logistic growth model. Among these, KGE7 has the highest biomass production (2.05 +/- 0.35 g L-1), lipid productivity (0.82 +/- 0.14 g L-1), and C16-C18 fatty acid contents (97.6 %). These results suggest that Scenedesmus sp. KGE 7 can be utilized for biodiesel production based on its high biomass and lipid productivity.
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  255. Isolation, mutagenesis, and optimization of cultivation conditions of microalgal strains for biodiesel production
    Abstract

    Zayadan, B. K.; Purton, S.; Sadvakasova, A. K.; Userbaeva, A. A.; Bolatkhan, K. 2014. Isolation, mutagenesis, and optimization of cultivation conditions of microalgal strains for biodiesel production. Russian Journal of Plant Physiology. 61(1) 124-130

    Algalogically pure cultures were isolated from different aquatic ecosystems and identified as representatives of green algae, euglena algae, and cyanobacteria. Isolated cultures and collection strains of microalgae were screened for productivity. Induced mutagenesis (exposure to UV radiation, 254 nm, 40 Erg/mm(2)) and selection yielded a mutant strain C-2m2 of Chlorella pyrenoidosa notable for a high activity of lipid biosynthesis and accumulation. Optimization of its culture conditions was conducted. It was found that the active lipid accumulation by the cells of C. pyrenoidosa strain C-2m2 occurred when nitrogen concentration in the medium was tenfold reduced (to the level of 0.004 g/L) at an illuminance of 4 klx.
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  256. Joint production of biodiesel and bioethanol from filamentous oleaginous microalgae Tribonema sp.
    Abstract

    Wang, H.; Ji, C. L.; Bi, S. L.; Zhou, P.; Chen, L.; Liu, T. Z. 2014. Joint production of biodiesel and bioethanol from filamentous oleaginous microalgae Tribonema sp.. Bioresource Technology. 172169-173

    Making full use of lipid and carbohydrate in microalgae for joint production of biodiesel and bioethanol may create a potential way to cut the high cost of single biofuel production from microalgae. Compared with conventional unicellular oleaginous microalgae, filamentous microalgae Tribonema sp. is richer in lipid and carbohydrate contents and lower protein content, thus, this study explores the suitability of Tribonema sp. as a substrate for joint production of biodiesel and bioethanol. Acid hydrolysis is the key step to saccharify wall cell into fermentable sugar and release lipid. Microalgae biomass (50 g/L) was acid (3% H2SO4) hydrolyzed at 121 degrees C for 45 min to reach the maximum hydrolysis efficiency (81.48%). Subsequently, the lipid separated with hexane-ethanol from the hydrolysate was converted into microalgae biodiesel and the conversion rate was 98.47%. With yeast Saccharomyces cerevisiae, the maximum ethanol yield of 56.1% was reached from 14.5 g/L glucose in hydrolysate. (C) 2014 Elsevier Ltd. All rights reserved.
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  257. Kinetic and thermodynamic studies on biodiesel production from Spirulina platensis algae biomass using single stage extraction-transesterification process
    Abstract

    Nautiyal, P.; Subramanian, K. A.; Dastidar, M. G. 2014. Kinetic and thermodynamic studies on biodiesel production from Spirulina platensis algae biomass using single stage extraction-transesterification process. Fuel. 135228-234

    Biodiesel production from nonedible feedstocks is gaining attention in the recent years as they do not interfere with the global food economy. In this investigation, Spirulina platensis algae biomass was used as the feedstock for biodiesel production. Single stage extraction-transesterification was carried out with an aim to study the effect of reaction temperature, catalyst concentration, algae biomass to methanol ratio (wt:vol), stirring intensity and algae drying duration on the biodiesel yield. The optimum conditions for maximum biodiesel yield (75 +/- 0.40%) were found to be 90 min duration for algae drying, 60% catalyst concentration, 1:4 algae biomass to methanol ratio, 450 rpm stirring intensity and 55 degrees C reaction temperature. The experimental data appeared to be a good fit with the first order reaction kinetics. For the reaction studied at different temperatures, values of rate constant and activation energy were found out to be 0.001 min (1) and 14518.51 J/mol respectively. The values of thermodynamic parameters such as Gibbs free energy (Delta G), enthalpy of activation (Delta H) and entropy of activation (Delta S) were also determined. The positive values of DG and DH and negative value of DS indicated the unspontaneous and endergonic nature of the reaction. (C) 2014 Elsevier Ltd. All rights reserved.
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  258. Large-scale biodiesel production using flue gas from coal-fired power plants with Nannochloropsis microalgal biomass in open raceway ponds
    Abstract

    Zhu, B. H.; Sun, F. Q.; Yang, M.; Lu, L.; Yang, G. P.; Pan, K. H. 2014. Large-scale biodiesel production using flue gas from coal-fired power plants with Nannochloropsis microalgal biomass in open raceway ponds. Bioresource Technology. 17453-59

    The potential use of microalgal biomass as a biofuel source has raised broad interest. Highly effective and economically feasible biomass generating techniques are essential to realize such potential. Flue gas from coal-fired power plants may serve as an inexpensive carbon source for microalgal culture, and it may also facilitate improvement of the environment once the gas is fixed in biomass. In this study, three strains of the genus Nannochloropsis (4-38, KA2 and 75B1) survived this type of culture and bloomed using flue gas from coal-fired power plants in 8000-L open raceway ponds. Lower temperatures and solar irradiation reduced the biomass yield and lipid productivities of these strains. Strain 4-38 performed better than the other two as it contained higher amounts of triacylglycerols and fatty acids, which are used for biodiesel production. Further optimization of the application of flue gas to microalgal culture should be undertaken. (C) 2014 Elsevier Ltd. All rights reserved.
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  259. Life cycle assessment of biodiesel production from algal bio-crude oils extracted under subcritical water conditions
    Abstract

    Ponnusamy, S.; Reddy, H. K.; Muppaneni, T.; Downes, C. M.; Deng, S. G. 2014. Life cycle assessment of biodiesel production from algal bio-crude oils extracted under subcritical water conditions. Bioresource Technology. 170454-461

    A life cycle assessment study is performed for the energy requirements and greenhouse gas emissions in an algal biodiesel production system. Subcritical water (SCW) extraction was applied for extracting bio-crude oil from algae, and conventional transesterification method was used for converting the algal oil to biodiesel. 58 MJ of energy is required to produce 1 kg of biodiesel without any co-products management, of which 36% was spent on cultivation and 56% on lipid extraction. SCW extraction with thermal energy recovery reduces the energy consumption by 3-5 folds when compared to the traditional solvent extraction. It is estimated that 1 kg of algal biodiesel fixes about 0.6 kg of CO2. An optimized case considering the energy credits from co-products could further reduce the total energy demand. The energy demand for producing 1 kg of biodiesel in the optimized case is 28.23 MJ. (C) 2014 Elsevier Ltd. All rights reserved.
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  260. Life cycle assessment on microalgal biodiesel production using a hybrid cultivation system
    Abstract

    Adesanya, V. O.; Cadena, E.; Scott, S. A.; Smith, A. G. 2014. Life cycle assessment on microalgal biodiesel production using a hybrid cultivation system. Bioresource Technology. 163343-355

    A life cycle assessment (LCA) was performed on a putative biodiesel production plant in which the freshwater alga Chlorella vulgaris, was grown using an existing system similar to a published commercial-scale hybrid cultivation. The hybrid system couples airlift tubular photobioreactors with raceway ponds in a two-stage process for high biomass growth and lipid accumulation. The results show that microalgal biodiesel production would have a significantly lower environmental impact than fossil-derived diesel. Based on the functional unit of 1 ton of biodiesel produced, the hybrid cultivation system and hypothetical downstream process (base case) would have 42% and 38% savings in global warming potential (GWP) and fossil-energy requirements (FER) when compared to fossil-derived diesel, respectively. Sensitivity analysis was performed to identify the most influential process parameters on the LCA results. The maximum reduction in GWP and FER was observed under mixotrophic growth conditions with savings of 76% and 75% when compared to conventional diesel, respectively. (c) 2014 Elsevier Ltd. All rights reserved.
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  261. Life cycle cost of biodiesel production from microalgae in Thailand
    Abstract

    Sawaengsak, W.; Silalertruksa, T.; Bangviwat, A.; Gheewala, S. H. 2014. Life cycle cost of biodiesel production from microalgae in Thailand. Energy for Sustainable Development. 1867-74

    Biofuels derived from microalgae are currently gaining attention as alternative fuels, especially for substituting biodiesel. Microalgae can be grown either in open pond systems or in closed photobioreactors. However, the systems require a high initial capital investment for construction of pond and photobioreactor systems. This study aims to evaluate the financial feasibility of two types of large scale microalgae-based biodiesel production assumed to be located in the northern region of Thailand. Four algae-to-biofuels process scenarios were examined: base cases of raceway ponds and photobioreactors including only biodiesel production; and alternative cases for both, including extraction of high value added products, omega-3 fatty acids, in addition to biodiesel. The basis of biodiesel production was 720,000 L per year operated for 15 years. For the base case, the biodiesel production costs for algae produced from raceway ponds and photobioreactors were 68 and 224 Thai Baht/L, respectively, while for the alternative case, they were 191 and 450 Thai Baht/L, respectively. Even though the omega-3 fatty acid production gained higher revenue, the capital cost and operating cost would need to be reduced at least 50% to make the systems profitable. Several improvement options and possible government incentives to achieve this are presented. (C) 2013 International Energy Initiative. Published by Elsevier Inc All rights reserved.
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  262. Life Cycle GHG Emissions from Microalgal Biodiesel - A CA-GREET Model
    Abstract

    Woertz, I. C.; Benemann, J. R.; Du, N.; Unnasch, S.; Mendola, D.; Mitchell, B. G.; Lundquist, T. J. 2014. Life Cycle GHG Emissions from Microalgal Biodiesel - A CA-GREET Model. Environmental Science & Technology. 48(11) 6060-6068

    A life cycle assessment (LCA) focused on greenhouse gas (GHG) emissions from the production of microalgal biodiesel was carried out based on a detailed engineering and economic analysis. This LCA applies the methodology of the California Low Carbon Fuel Standard (CA LCFS) and uses life cycle inventory (LCI) data for process inputs, based on the California-Modified Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (CA GREET) model. Based on detailed mass and energy balances, calculated GHG emissions from this algal biodiesel system are 70% lower than those of conventional diesel fuel, meeting the minimum 50% GHG reduction requirements under the EPA RFS2 and 60% for the European Union Renewable Energy Directive. This LCA study provides a guide to the research and development objectives that must be achieved to meet both economic and environmental goals for microalgae biodiesel production.
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  263. Life cycle GHG emissions from microalgal biodiesel--a CA-GREET model
    Abstract

    Woertz, I. C.; Benemann, J. R.; Du, N.; Unnasch, S.; Mendola, D.; Mitchell, B. G.; Lundquist, T. J. 2014. Life cycle GHG emissions from microalgal biodiesel--a CA-GREET model. Environ Sci Technol. 48(11) 6060-8

    A life cycle assessment (LCA) focused on greenhouse gas (GHG) emissions from the production of microalgal biodiesel was carried out based on a detailed engineering and economic analysis. This LCA applies the methodology of the California Low Carbon Fuel Standard (CA LCFS) and uses life cycle inventory (LCI) data for process inputs, based on the California-Modified Greenhouse Gases, Regulated Emissions, and Energy use in Transportation (CA GREET) model. Based on detailed mass and energy balances, calculated GHG emissions from this algal biodiesel system are 70% lower than those of conventional diesel fuel, meeting the minimum 50% GHG reduction requirements under the EPA RFS2 and 60% for the European Union Renewable Energy Directive. This LCA study provides a guide to the research and development objectives that must be achieved to meet both economic and environmental goals for microalgae biodiesel production.
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  264. Lipid extraction from Scenedesmus sp microalgae for biodiesel production using hot compressed hexane
    Abstract

    Shin, H. Y.; Ryu, J. H.; Bae, S. Y.; Crofcheck, C.; Crocker, M. 2014. Lipid extraction from Scenedesmus sp microalgae for biodiesel production using hot compressed hexane. Fuel. 13066-69

    Lipid extraction from Scenedesmus sp. microalgae using hot compressed hexane (HCH) was investigated. Extraction performance was evaluated near the critical point of hexane and was compared with that of hexane extraction performed at room temperature and pressure, and the Bligh and Dyer extraction method. Experimental data showed that HCH significantly improves the lipid yield and rate of lipid extraction compared to the use of hexane at ambient conditions. High yields of biodiesel-convertible lipid fractions were rapidly achieved at the critical point of hexane, at a level comparable to that of the Bligh and Dyer method. (C) 2014 Elsevier Ltd. All rights reserved.
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  265. Lipids extraction from microalgae for biodiesel production
    Abstract

    Sanchez, A.; Cancela, A.; Maceiras, R.; Alfonsin, V. 2014. Lipids extraction from microalgae for biodiesel production. 2014 International Renewable and Sustainable Energy Conference (Irsec). 921-924

    Microalgae are being used as an alternative raw material for biodiesel production. This purpose involves the microalgae cultivation, biomass harvesting, lipids extraction and transesterification. In this work, different methods for lipids extraction from Chlorella Vulgaris are evaluated. The different extractions were carried out using Soxhlet method or ultrasound irradiation. In both cases, different solvents were used. Among the analyzed methods, the methanol extraction assisted by ultrasound resulted in the highest extraction of Chlorella Vulgaris oil.
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  266. Microalgae Isolation and Selection for Prospective Biodiesel Production
    Abstract

    Duong, V. T.; Li, Y.; Nowak, E.; Schenk, P. M. 2014. Microalgae Isolation and Selection for Prospective Biodiesel Production. Advances in Biofuel Production: Algae and Aquatic Plants. 257-276

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  267. Microalgae-mediated simultaneous treatment of toxic thiocyanate and production of biodiesel
    Abstract

    Ryu, B. G.; Kim, J.; Yoo, G.; Lim, J. T.; Kim, W.; Han, J. I.; Yang, J. W. 2014. Microalgae-mediated simultaneous treatment of toxic thiocyanate and production of biodiesel. Bioresource Technology. 158166-173

    In this work, a method for simultaneously degrading the toxic pollutant, thiocyanate, and producing microalgal lipids using mixed microbial communities was developed. Aerobic activated sludge was used as the seed culture and thiocyanate was used as the sole nitrogen source. Two cultivation methods were sequentially employed: a lithoautotrophic mode and a photoautotrophic mode. Thiocyanate hydrolysis and a nitrification was found to occur under the first (lithoautotrophic) condition, while the oxidized forms of nitrogen were assimilated by the photoautotrophic consortium and lipids were produced under the second condition. The final culture exhibited good settling efficiency (similar to 70% settling over 10 min), which can benefit downstream processing. The highest CO2 fixation rate and lipid productivity were observed with 2.5% and 5% CO2, respectively. The proposed integrated algal-bacterial system appears to be a feasible and even beneficial option for thiocyanate treatment and production of microbial lipids. (C) 2014 Elsevier Ltd. All rights reserved.
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  268. Microalgal biodiesel from Isochrysis sp
    Abstract

    Burlow, N.; Williams, J.; Culler, A.; Corliss, J.; Gilbert, G.; O'Neil, G. W. 2014. Microalgal biodiesel from Isochrysis sp. Abstracts of Papers of the American Chemical Society. 247

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  269. Mixed Trophic State Production Process for Microalgal Biomass with High Lipid Content for Generating Biodiesel and Biogas
    Abstract

    Bohutskyi, P.; Kula, T.; Kessler, B.; Hong, Y.; Bouwer, E. J.; Betenbaugh, M. J.; Allnutt, F. C. T. 2014. Mixed Trophic State Production Process for Microalgal Biomass with High Lipid Content for Generating Biodiesel and Biogas. Bioenergy Research. 7(4) 1174-1185

    Economically feasible and sustainable energy production from microalgae requires optimization of algal growth, maximization of lipid content, and enhancement of biomass conversion into energy. An innovative, mixed trophic state process with high productivity was implemented to generate microalgae with high lipid content for generating biodiesel and biogas. Auxenochlorella protothecoides, a unicellular green alga, was grown phototrophically to 0.28 dry weight per L (gdw/L) then concentrated to 36 gdw/L for use as an inoculum for a subsequent heterotrophic cultivation to a final density of nearly 120 gdw/L. Simultaneous nitrogen deprivation and glucose supplementation during the heterotrophic stage increased the total lipid content from 16 to 57 % while the triacylglycerol (TAG) fraction of total lipids advanced from 2 to 79 %. Productivity peaked at 4.9 g of biomass/L-h and 1.7 g TAGs/L-h. The extracted lipids, including high levels of oleic, linoleic, and palmitic acids, were converted into biodiesel with a predicted cetane number of 56.4 and low concentrations of long-chain saturated and polyunsaturated fatty acid methyl esters. Both intact microalgal biomass and lipid-extracted algal residues (LEA) were good substrates for anaerobic digestion (AD) with methane yields of 0.6 and 0.4 L/g volatile solids (VS), respectively. These yields represented nearly 80 % of theoretical methane potential. LEA, with a favorable carbon to nitrogen ratio (C:N) of approximately 19:1, is an appropriate substrate for anaerobic microorganisms, most likely because it contains essential nutrients required for microbial digestion. The biochemical composition of the biomass, especially its lipid content, is the major contributor for energy output. As a result, coupling biodiesel production with AD of LEA to generate methane can increase the overall process' energy output up to 40 %.
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  270. Mixotrophic cultivation of green microalgae Scenedesmus obliquus on cheese whey permeate for biodiesel production
    Abstract

    Girard, J. M.; Roy, M. L.; Ben Hafsa, M.; Gagnon, J.; Faucheux, N.; Heitz, M.; Tremblay, R.; Deschenes, J. S. 2014. Mixotrophic cultivation of green microalgae Scenedesmus obliquus on cheese whey permeate for biodiesel production. Algal Research-Biomass Biofuels and Bioproducts. 5241-248

    Microalgae mass cultivation for biodiesel production might very well become the next marketable biofuel. The main challenge to overcome however is the development of high efficiency strategies for the large-scale production of oleaginous microalgae at low costs. In the present work, the use of cheese whey permeate (WP) in mixotrophic microalgae cultures is proposed. Pure lactose, the main constituent of WP (>80% w/w of the total dissolved solids), can support Scenedesmus growth under heterotrophic culture conditions (absence of light). Substituting 40% (v/v) of the culture medium with WP significantly stimulates Scenedesmus obliquus growth undermixotrophic (mu(max) = 1.083 +/- 0.030 day(-1)) and heterotrophic (mu(max) = 0.702 +/- 0.025 day(-1)) conditions, compared to photoautotrophic control cultures (mu(max) = 0.267 +/- 0.083 day(-1)). As growth occurs in the presence of lactose, a significant reduction of its concentration is observed, while the galactose and glucose concentrations actually increase in the culture medium. Culture medium analyses showed complete exhaustion of extracellular nitrogen (nitrate and ammonium), while intracellular lipid analyses showed neutral lipid (NL) accumulation, particularly under conditions of high pH (>9.5). Photoautotrophic control cultures accumulated more lipids (per dryweight) than WP-supplemented cultures, an aspect which is discussed in the context of lipid enrichment strategies. A fast and simple method for NL cellular content estimation is also described. (C) 2014 Elsevier B.V. All rights reserved.
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  271. Mixotrophic cultivation of microalgae for biodiesel production: status and prospects
    Abstract

    Wang, J.; Yang, H.; Wang, F. 2014. Mixotrophic cultivation of microalgae for biodiesel production: status and prospects. Appl Biochem Biotechnol. 172(7) 3307-29

    Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgae can be produced under three major cultivation modes, namely photoautotrophic cultivation, heterotrophic cultivation, and mixotrophic cultivation. Potentials and practices of biodiesel production from microalgae have been demonstrated mostly focusing on photoautotrophic cultivation; mixotrophic cultivation of microalgae for biodiesel production has rarely been reviewed. This paper summarizes the mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes. Influencing factors of microalgal biodiesel production under mixotrophic cultivation are presented, development of combining microalgal biodiesel production with wastewater treatment is especially reviewed, and bottlenecks and strategies for future commercial production are also identified.
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  272. Mixotrophic Cultivation of Microalgae for Biodiesel Production: Status and Prospects
    Abstract

    Wang, J. H.; Yang, H. Z.; Wang, F. 2014. Mixotrophic Cultivation of Microalgae for Biodiesel Production: Status and Prospects. Applied Biochemistry and Biotechnology. 172(7) 3307-3329

    Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgae can be produced under three major cultivation modes, namely photoautotrophic cultivation, heterotrophic cultivation, and mixotrophic cultivation. Potentials and practices of biodiesel production from microalgae have been demonstrated mostly focusing on photoautotrophic cultivation; mixotrophic cultivation of microalgae for biodiesel production has rarely been reviewed. This paper summarizes the mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes. Influencing factors of microalgal biodiesel production under mixotrophic cultivation are presented, development of combining microalgal biodiesel production with wastewater treatment is especially reviewed, and bottlenecks and strategies for future commercial production are also identified.
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  273. New Type of Extraction Solvent for Algal Oils: Fatty Acid Methyl Esters
    Abstract

    Park, C. W.; Huang, W. C.; Gim, S.; Lee, K. S.; Kim, J. D. 2014. New Type of Extraction Solvent for Algal Oils: Fatty Acid Methyl Esters. Acs Sustainable Chemistry & Engineering. 2(12) 2653-2657

    We propose a new process of biodiesel production that utilizes biodiesel as an extractant for lipid extraction from fresh microalgae. Biodiesel-based extractant showed high lipid extraction efficiency from dried Chlorella. The efficiency obtained from the biodiesel-based extractant was comparable to the chloroform/methanol method, while the required amount of solvents was smaller than the chloroform/methanol method. Furthermore, fatty acid methyl esters displayed successful penetration through the cell membrane of wet algae in an aqueous environment, and this result suggests that the biodieselbased extractant has potential for wet extraction.
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  274. Novel electrochemical method for the recovery of lipids from microalgae for biodiesel production
    Abstract

    Daghrir, R.; Igounet, L.; Brar, S. K.; Drogui, P. 2014. Novel electrochemical method for the recovery of lipids from microalgae for biodiesel production. Journal of the Taiwan Institute of Chemical Engineers. 45(1) 153-162

    The performance of electrochemical process for efficient extraction of lipids and proteins from Chlorella vulgaris as microalgae was studied. The process was evaluated in terms of its capability of simultaneously extracting lipids and proteins using different types of anode materials (Ti/IrO2, Ti, Ti/SnO2 and Ti/PbO2). Relatively higher extraction of lipids (3.27% g(Lip)/g(dry) (wt)) and proteins (39.91 mg/L) was reported using Ti/IrO2 material at the anode. Factorial design (FD) and central composite design (CCD) methodologies were successively used to define the optimal operating conditions to reach maximum extraction of lipids and proteins from microalgae. Current intensity and recycling flow rate were found to influence the lipids and proteins extraction. The contribution of recycling flow rate on the lipids and proteins extraction was around 61.72% and 53.80%, respectively, whereas the contribution of current intensity on lipids and proteins extraction was around 22.63% and 21.83%, respectively. The electrochemical treatment applied under 0.6 A of current intensity and 394.51 mL/min of recycling flow rate during 100 mm of electrolysis time was found to be the optimal operating condition in terms of cost/ effectiveness. Under these optimal conditions, 5.53 +/- 0.23% g(Lip)/g(dry) (wt) of lipid and 120.20 +/- 2.05 mg/L of proteins were reported. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier BAT. All rights reserved.
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  275. Optimal Design of an Integrated Microalgae Biorefinery for the Production of Biodiesel and PHBs
    Abstract

    Prieto, C. V. G.; Ramos, F. D.; Estrada, V.; Diaz, M. S. 2014. Optimal Design of an Integrated Microalgae Biorefinery for the Production of Biodiesel and PHBs. Iconbm: International Conference on Biomass, Pts 1 and 2. 37319-324

    In this work, we formulate a nonlinear programming model for the design of an integrated microalgae-based biorefinery for the production of biodiesel and value added co-products which depend on the particular microalgae species considered. The production of biogas by anaerobic digestion of the oil cake together with waste streams is included.
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  276. Optimization and characterization of biodiesel production from microalgae Botryococcus grown at semi-continuous system
    Abstract

    Ashokkumar, V.; Agila, E.; Sivakumar, P.; Salam, Z.; Rengasamy, R.; Ani, F. N. 2014. Optimization and characterization of biodiesel production from microalgae Botryococcus grown at semi-continuous system. Energy Conversion and Management. 88936-946

    The indigenous strain Botryococcus braunii TN101 was isolated and acclimatized under laboratory condition. Upstream and downstream process was thoroughly explored for biofuel production. During semi-continuous cultivation, the alga was grown under batch mode for 6 days; thereafter 40% of algal culture was harvested at every three days interval. At semi-continuous system, the indigenous strain grows well and produces high biomass productivity of 33.8 g m(-3) day(-1). A two step combined harvesting process was designed using ferric iron and organic polymer Poly-(D)glucosamine and harvested 99.5% of biomass. Lipid extraction was optimized using different solvents, cyclohexane and methanol at 3:1 ratio supported for maximum extraction of lipids in Botryococcus up to 26.3%. Physicochemical properties of lipid was analyzed and found, saponification values 184, ester values 164, iodine values 92 and the average molecular weight of the lipids are 920 g mol(-1). The lipid contains 9.7% of FFA level, therefore, a simultaneous esterification and transesterification of free fatty acids and triacylglycerides were optimized for biodiesel production and the methyl ester yield was recorded up to 84%. In addition, an optimization study was carried out for the removal of pigments present in the biodiesel; the result revealed that 99% of pigments were removed from the biodiesel using activated charcoal. The biodiesel profile was analyzed by H-1 and C-13 NMR and GC-MS analyzer, methyl palmitate and methyl oleate was the major fatty acid found. Based on the areal and volumetric biomass productivity, it is estimated that the indigenous strain can produce 101 tons ha(-1) year(-1) of biomass. (C) 2014 Elsevier Ltd. All rights reserved.
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  277. Perspectives and advances of microalgal biodiesel production with supercritical fluid technology
    Abstract

    Zeng, D.; Li, R. S.; Yan, T.; Fang, T. 2014. Perspectives and advances of microalgal biodiesel production with supercritical fluid technology. Rsc Advances. 4(75) 39771-39781

    Biodiesel, a sustainable and clean energy source, has been greatly attracting interest to compete against serious challenges like energy crisis and environmental pollution. Microalgae are currently promoted as a biodiesel feedstock with the most potential and advantages of high lipid content and productivity. This paper provides an overview on a selection of microalgal strains, supercritical carbon dioxide (SCCO2) extraction of microalgal lipids and the advances of microalgae oils transesterification for producing biodiesel with supercritical alcohols. In particular, a two-step process of microalgal biodiesel production using supercritical technology and the following SCCO2 extraction are generalized in this study. Considering the commercialization of microalgal biodiesel in the future, the cost of microalgal biodiesel published in recent literature is analysed. Furthermore, feasible strategies for improvement are proposed. The overall economic efficiency of microalgal biodiesel industry can be improved by the multi-effect co-production coupling technology.
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  278. Potential Biodiesel Production from Four Green Microalgae Cultures Collected off the Lebanese Coast
    Abstract

    Saleh, D.; Hanna, L.; Abdelkader, O.; Mouneimne, Y.; Bouhadir, K.; Saoud, I.; Tzovenis, I.; Abou Jawdah, Y. 2014. Potential Biodiesel Production from Four Green Microalgae Cultures Collected off the Lebanese Coast. 2014 International Conference on Renewable Energies for Developing Countries (REDEC). 230-235

    Seawater samples were collected from various locations along the Lebanese coast. Four unilagal isolates were acquired using streaking and serial dilution methods. The four isolates were cultured in 20 L flat photo-bioreactors containing seawater fertilized with Guillards F/2 medium. The growth dynamics, dry matter yield, lipid content, fatty acid profile and potential biodiesel yield were determined. The lipid content varied among growth phases and was greatest in the stationary phase, where it ranged between 14.5% DW in the Jod isolate and 16.5% DW in Jbd isolate. The best microalgal isolate tested gave a biodiesel production of around 50mg/L. Optimization of culture conditions to improve biodiesel yield and the search for better performing local phytoplankton species are in progress.
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  279. Pretreatment and kinetics of oil extraction from algae for biodiesel production
    Abstract

    Derakhshan, M. V.; Nasernejad, B.; Dadvar, M.; Hamidi, M. 2014. Pretreatment and kinetics of oil extraction from algae for biodiesel production. Asia-Pacific Journal of Chemical Engineering. 9(5) 629-637

    In this study, extraction of lipid from algal sp. Chlorella vulgaris is investigated based on Bligh and Dyer method employing methanol and chloroform on wet biomass. Optimization methodology was established on comparison of pretreatment methods as well as investigation of ultrasonication and stirrer parameters to enhance cell disruption. It was found that biomass with water/solid proportion (w/s = 5) operating temperature of 50 degrees C both for ultrasonication and shaking, 5 min ultrasonication with further 3 h of stirring with 200 rpm is the best set of parameters for breakdown of cell envelops, and using these parameters, total extraction of 22.07% was obtained. Kinetic study of breakdown was carried out with further full-factorial investigation of extraction (%) vs time and temperature. Using Arrhenius equation, activation energy of about 34.73 kJ/mol was obtained for this algal sp. with R-2 = 97.81%. Further analysis using analysis of variance showed that when using lower temperatures, sudden increase of extraction occurs in longer times, and vice versa, hence emphasizing the interaction thereof. It was also found that temperature plays the vital role among all examined parameters. (C) 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
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  280. Production and characterization of biodiesel from algae
    Abstract

    Nautiyal, P.; Subramanian, K. A.; Dastidar, M. G. 2014. Production and characterization of biodiesel from algae. Fuel Processing Technology. 12079-88

    The feasibility of biodiesel production from microalgae as third generation biodiesel feedstock was studied in the present investigation. The studies were conducted to evaluate the growth patterns of the algae species i.e. Spirulina, Chlorella and pond water algae. The oil was extracted from the algae biomass and then transesterified. Simultaneous extraction and transesterification were also studied using different solvents. Maximum biodiesel yield was obtained using simultaneous extraction and transesterification using hexane as a solvent. The systematic characterization of algae biomass, algae oil and algae biodiesel was carried out to establish the potential of microalgae for biodiesel production. (C) 2013 Elsevier B.V. All rights reserved.
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  281. Production of biodiesel from carbon sources of macroalgae, Laminaria japonica
    Abstract

    Xu, X.; Kim, J. Y.; Oh, Y. R.; Park, J. M. 2014. Production of biodiesel from carbon sources of macroalgae, Laminaria japonica. Bioresource Technology. 169455-461

    As aquatic biomass which is called "the third generation biomass'', Laminaria japonica (also known as Saccharina japonica) consists of mannitol and alginate which are the main polysaccharides of algal carbohydrates. In this study, oleaginous yeast (Cryptococcus curvatus) was used to produce lipid from carbon sources derived from Laminaria japonica. Volatile fatty acids (VFAs) were produced by fermentation of alginate extracted from L. japonica. Thereafter, mannitol was mixed with VFAs to culture the oleaginous yeast. The highest lipid content was 48.30%. The composition of the fatty acids was similar to vegetable oils. This is the first confirmation of the feasibility of using macroalgae as a carbon source for biodiesel production. (C) 2014 Elsevier Ltd. All rights reserved.
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  282. Production of Biodiesel from Microalgae
    Abstract

    Danilovic, B. R.; Avramovic, J. M.; Ciric, J. T.; Savic, D. S.; Veljkovic, V. B. 2014. Production of Biodiesel from Microalgae. Hemijska Industrija. 68(2) 213-232

    In recent years, more attention has been paid to the use of third generation feedstocks for the production of biodiesel. Microalgae have emerged as one of the most promising sources for biodiesel production. They are unicellular or colonial photosynthetic organisms, with permanently increasing role in industrial application in the production. of not only chemicals and nutritional supplements, but also the biodiesel. The biodiesel productivity per hectare of cultivation area can be up to 100 times higher for microalgae than for oil crops. Also, microalgae can grow in a variety of environments that are often unsuitable for agricultural purposes. Microalgae oil content varies in different species and can reach Lip to 77% of dry biomass, while the oil productivity by the phototrophic cultivation of microalgae is up to 122 mg/l/d. Variations of the growth conditions and the implementation of the genetic engineering can induce the changes in the composition and productivity of microalgae oil. Biodiesel from microalgae can be produced in two ways: by transesterification of oil extracted from biomass or by direct transesterification of algal biomass (so called in situ transesterification). This paper reviews the curent status of microalgae used for the production of biodiesel including their isolation, cultivation, harvesting and conversion to biodiesel. Because of high Oil productivity, microalgae will play a significant role in future biodiesel production. The advantages of using microalgae as a source for biofuel production are increased efficiency and reduced cost of production. Also, microalgae do not require a lot of space for growing and do not have a negative impact on the global food and water supplies. Disadvantages of using microalgae are more difficult separation of biomass and the need for further research to develop standardized methods for microalgae cultivation and biodiesel production. Currently, microalgae are not yet sustainable option for the commercial production of biodiesel. First of all, the price of biodiesel from microalgae is still higher than the price of diesel, due to high production costs.
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  283. Production of marine microalgal biodiesel through interesterification using novel Bacillus lipase
    Abstract

    Duraiarasan, S.; Mani, V. 2014. Production of marine microalgal biodiesel through interesterification using novel Bacillus lipase. J Microbiol Biotechnol.

    In this study, enzymatic interesterification is carried out using encapsulated lipase as biocatalyst with methyl acetate as acyl acceptor in a solvent free system. Lipase, isolated from a marine bacterial isolate. Bacillus sp.S23 (KF220659.1) was immobilized in a sodium alginate beads. This investigation elaborated on the effects of various parameters namely enzyme loading, temperature, water, molar ratio, reaction time and agitation for interesterification. The study resulted in the following optimal conditions- 1.5 g immobilised lipase, 1:12 molar ratio of oil to methyl acetate, 35 degrees C, 8 % water, 60 h reaction time, 250 rpm of agitation. With the standardized condition, the maximum conversion efficiency was 95.68%. The immobilized beads, even after 10 cycles of repeated usage showed high stability in the presence of methyl acetate and no loss of lipase activity. The microalgal biodiesel composition was analysed by Gas Chromatography. The current study was efficient in using immobilized lipase for interesterification process, as the method turned to be cost effective and ecofriendly, no solvent was involved and enzyme being encapsulated in a natural polymer.
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  284. Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris
    Abstract

    Hu, Q.; Zeng, R.; Zhang, S. X.; Yang, Z. H.; Huang, H. 2014. Production of Microalgal Lipids as Biodiesel Feedstock with Fixation of CO2 by Chlorella vulgaris. Food Technology and Biotechnology. 52(3) 285-291

    The global warming and shortage of energy are two critical problems for human social development. CO2 mitigation and replacing conventional diesel with biodiesel are effective routes to reduce these problems. Production of microalgal lipids as biodiesel feedstock by a freshwater microalga, Chlorella vulgaris, with the ability to fixate CO2 is studied in this work. The results show that nitrogen deficiency, CO2 volume fraction and photoperiod are the key factors responsible for the lipid accumulation in C. vulgaris. With 5 % CO2, 0.75 g/L of NaNO3 and 18:6 h of light/dark cycle, the lipid content and overall lipid productivity reached 14.5 % and 33.2 mg/(L.day), respectively. Furthermore, we proposed a technique to enhance the microalgal lipid productivity by activating acetyl-CoA carboxylase (ACCase) with an enzyme activator. Citric acid and Mg2+ were found to be efficient enzyme activators of ACCase. With the addition of 150 mg/L of citric acid or 1.5 mmol/L of MgCl2, the lipid productivity reached 39.1 and 38.0 mg/(L.day), respectively, which was almost twofold of the control. This work shows that it is practicable to produce lipids by freshwater microalgae that can fixate CO2, and provides a potential route to solving the global warming and energy shortage problems.
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  285. Proximate composition, total phenolics content and antioxidant activities of microalgal residue from biodiesel production
    Abstract

    Pumas, P.; Pumas, C. 2014. Proximate composition, total phenolics content and antioxidant activities of microalgal residue from biodiesel production. Maejo International Journal of Science and Technology. 8(2) 122-128

    In biodiesel production, lipid is extracted from algal biomass but some beneficial substances may remain in its residue. In this study proximate composition, total phenolics content and antioxidant activities of a microalgal residue after lipid extraction were determined. It was found that the residue has a high protein content and the hot aqueous extract of the residue is high in both the phenolics content and the level of antioxidant activities.
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  286. Rapid biodiesel production using wet microalgae via microwave irradiation
    Abstract

    Wahidin, S.; Idris, A.; Shaleh, S. R. M. 2014. Rapid biodiesel production using wet microalgae via microwave irradiation. Energy Conversion and Management. 84227-233

    The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production. (C) 2014 Elsevier Ltd. All rights reserved.
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  287. Reducing electrocoagulation harvesting costs for practical microalgal biodiesel production
    Abstract

    Dassey, A. J.; Theegala, C. S. 2014. Reducing electrocoagulation harvesting costs for practical microalgal biodiesel production. Environmental Technology. 35(6) 691-697

    Electrocoagulation has shown potential to be a primary microalgae harvesting technique for biodiesel production. However, methods to reduce energy and electrode costs are still necessary for practical application. Electrocoagulation tests were conducted on Nannochloris sp. and Dunaliella sp. using perforated aluminium and iron electrodes under various charge densities. Aluminium electrodes were shown to be more efficient than iron electrodes when harvesting both algal species. Despite the lower harvesting efficiency, however, the iron electrodes were more energy and cost efficient. Operational costs of less than $0.03/L oil were achieved when harvesting Nannochloris sp. with iron electrodes at 35% harvest efficiency, whereas aluminium electrodes cost $0.75/L oil with 42% harvesting efficiency. Increasing the harvesting efficiencies for both aluminium and iron electrodes also increased the overall cost per litre of oil, therefore lower harvesting efficiencies with lower energy inputs was recommended. Also, increasing the culturing salinity to 2 ppt sodium chloride for freshwater Nannochloris sp. was determined practical to improve the electrocoagulation energy efficiency despite a 25% reduction in cell growth.
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  288. Regulatory function of organic carbon supplementation on biodiesel production during growth and nutrient stress phases of mixotrophic microalgae cultivation
    Abstract

    Chandra, R.; Rohit, M. V.; Swamy, Y. V.; Mohan, S. V. 2014. Regulatory function of organic carbon supplementation on biodiesel production during growth and nutrient stress phases of mixotrophic microalgae cultivation. Bioresource Technology. 165279-287

    Critical role of organic carbon supplementation on the lipid synthesis during growth and nutrient deprived stress phase was investigated in present study. Mixotrophic cultivation showed relatively higher biomass productivity at lower carbon loading condition (500 mg COD/l). Nutrient deprivation induced physiological stress and glucose supplementation with 2000 mg COD/l supported higher lipid accumulation (26%). Glucose supplementation in mixotrophic growth phase showed distinct influence on biomass growth whereas glucose supplementation in nutrient starvation resulted in higher lipid storage. Compositional variation in FAME profile was observed with respect to saturated fatty acids when operated with increasing glucose concentrations. Mixotrophic mode of cultivation showed remarkable benefits of nutrient removal and organic carbon supplementation influenced greatly on biodiesel production which can be easily scaled up to pilot plant and large scale production facilities. (C) 2014 Elsevier Ltd. All rights reserved.
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  289. Response surface methodology as a decision-making tool for optimization of culture conditions of green microalgae Chlorella spp. for biodiesel production
    Abstract

    Kirrolia, A.; Bishnoi, N. R.; Singh, R. 2014. Response surface methodology as a decision-making tool for optimization of culture conditions of green microalgae Chlorella spp. for biodiesel production. Annals of Microbiology. 64(3) 1133-1147

    We have evaluated process optimization and the interactive effects of a number of variables using a Box-Behnken design of response surface methodology (RSM). The process variables nitrate, phosphate, glucose and pH were optimized to enhance the cell growth rate, lipid accumulation and other biochemical parameters of Chlorella spp. The most significant increase in lipid production (dry cell weight basis) occurred at limited concentrations of nitrate and phosphate, 1 % glucose and pH 7.5. The addition of nitrates during the mid-lag and mid-exponential phases produced the maximum inhibitory effect on lipid accumulation and the presence of yeast extract led to a further enhancement of lipid accumulation. Of all the media tested, BG-11 was the best suited medium for algal biomass production and chlorophyll content. A significant increase in algal biomass was observed in BG-11 supplemented with bicarbonate and glucose (1 %). The maximum specific growth rate observed was on 9th day of culturing. Results of optimization of process variables through response surface methodology and optimization of various other conditions reflect cutting edge research directed towards increasing algal biomass and lipid content for biodiesel production using an efficient economical technological approach.
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  290. Screening microalgae native to Quebec for wastewater treatment and biodiesel production
    Abstract

    Abdelaziz, A. E. M.; Leite, G. B.; Belhaj, M. A.; Hallenbeck, P. C. 2014. Screening microalgae native to Quebec for wastewater treatment and biodiesel production. Bioresource Technology. 157140-148

    Biodiesel production from microalgae lipids is being considered as a potential source of renewable energy. However, practical production processes will probably require the use of local strains adapted to prevailing climatic conditions. This report describes the isolation of 100 microalgal strains from freshwater lakes and rivers located in the vicinity of Montreal, Quebec, Canada. Strains were identified and surveyed for their growth on secondary effluent from a municipal wastewater treatment plant (La Prairie, QC, Canada) using a simple and high throughput microalgal screening method employing 12 well plates. The biomass and lipid productivity of these strains on wastewater were compared to a synthetic medium under different temperatures (10 +/- 2 degrees C and 22 +/- 2 degrees C) and a number identified that showed good growth at 10 degrees C, gave a high lipid content (ranging from 20% to 45% of dry weight) or a high capacity for nutrient removal. (C) 2014 Elsevier Ltd. All rights reserved.
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  291. Screening, growth medium optimisation and heterotrophic cultivation of microalgae for biodiesel production
    Abstract

    Jia, Z.; Liu, Y.; Daroch, M.; Geng, S.; Cheng, J. J. 2014. Screening, growth medium optimisation and heterotrophic cultivation of microalgae for biodiesel production. Appl Biochem Biotechnol. 173(7) 1667-79

    This article presents a study on screening of microalgal strains from the Peking University Algae Collection and heterotrophic cultivation for biodiesel production of a selected microalgal strain. Among 89 strains, only five were capable of growing under heterotrophic conditions in liquid cultures and Chlorella sp. PKUAC 102 was found the best for the production of heterotrophic algal biodiesel. Composition of the growth medium was optimised using response surface methodology and optimised growth conditions were successfully used for cultivation of the strain in a fermentor. Conversion of algal lipids to fatty acid methyl esters (FAMEs) showed that the lipid profile of the heterotrophically cultivated Chlorella sp. PKUAC 102 contains fatty acids suitable for biodiesel production.
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  292. Screening, Growth Medium Optimisation and Heterotrophic Cultivation of Microalgae for Biodiesel Production
    Abstract

    Jia, Z. C.; Liu, Y.; Daroch, M.; Geng, S.; Cheng, J. J. 2014. Screening, Growth Medium Optimisation and Heterotrophic Cultivation of Microalgae for Biodiesel Production. Applied Biochemistry and Biotechnology. 173(7) 1667-1679

    This article presents a study on screening of microalgal strains from the Peking University Algae Collection and heterotrophic cultivation for biodiesel production of a selected microalgal strain. Among 89 strains, only five were capable of growing under heterotrophic conditions in liquid cultures and Chlorella sp. PKUAC 102 was found the best for the production of heterotrophic algal biodiesel. Composition of the growth medium was optimised using response surface methodology and optimised growth conditions were successfully used for cultivation of the strain in a fermentor. Conversion of algal lipids to fatty acid methyl esters (FAMEs) showed that the lipid profile of the heterotrophically cultivated Chlorella sp. PKUAC 102 contains fatty acids suitable for biodiesel production.
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  293. Selection of microalgae for biodiesel production in a scalable outdoor photobioreactor in north China
    Abstract

    Xia, L.; Song, S. X.; He, Q. N.; Yang, H. J.; Hu, C. X. 2014. Selection of microalgae for biodiesel production in a scalable outdoor photobioreactor in north China. Bioresource Technology. 174274-280

    The aim of this study was to identify the most promising species as biodiesel feedstock for large-scale cultivation in north China. Eight species of microalgae, selected on the basis of indoor screening, were tested for lipid productivity and the suitability of their fatty acid profiles for biodiesel production under outdoor conditions. Among them, three species Desmodesmus sp. NMX451, Desmodesmus sp. T28-1 and Scenedesmus obtusus XJ-15 were selected for further characterization due to their possessing higher lipid productivities and favorable biodiesel properties. The best strain was S. obtusus XJ-15, with highest biomass productivity of 20.2 g m(-2) d(-1) and highest lipid content of 31.7% in a culture of 140 L. S. obtusus XJ-15 was further identified as the best candidate for liquid biofuel production, characterized by average areal growth rate of 23.8 g m(-2) d(-1) and stable lipid content of above 31.0% under a scale of 1400 L over a season. (C) 2014 Elsevier Ltd. All rights reserved.
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  294. Simultaneous Optimization and Heat Integration for the Coproduction of Diesel Substitutes: Biodiesel (FAME and FAEE) and Glycerol Ethers from Algae Oil
    Abstract

    Martin, M.; Grossmann, I. E. 2014. Simultaneous Optimization and Heat Integration for the Coproduction of Diesel Substitutes: Biodiesel (FAME and FAEE) and Glycerol Ethers from Algae Oil. Industrial & Engineering Chemistry Research. 53(28) 11371-11383

    In this paper, an optimal process for the simultaneous production of biodiesel (using methanol or bioethanol) and ethers of glycerol is proposed to increase the yield to diesel substitutes in current bio diesel production facilities. The problem is formulated as an optimization model including algae oil production, production of ethanol from starch, transesterification of the oil with bioethanol or methanol, etherification of glycerol with i-butene, which depends on a dynamic model to compute the complex chemical kinetics, and the purification of the ethers. Simultaneous optimization and heat integration are carried out and finally the water consumption of the integrated processes is optimized. Several comparisons are presented. First, the use of glycerol to produce ethers or as a byproduct. Second, the use of different alcohols for biodiesel synthesis in an integrated process. The production of glycerol ethers increases the yield of diesel substitutes by 20%. Furthermore, the energy and water consumptions are competitive with those processes when glycerol is the byproduct. For the integration of glycerol ethers with current biodiesel plants, the use of methanol instead of ethanol is cheaper. However, the current price of i-butene results in high production costs. Simultaneous production of ethanol, biodiesel and glyerol ethers reaches the target of $1/gal for biofuels production cost.
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  295. Study of the microwave lipid extraction from microalgae for biodiesel production
    Abstract

    Dai, Y. M.; Chen, K. T.; Chen, C. C. 2014. Study of the microwave lipid extraction from microalgae for biodiesel production. Chemical Engineering Journal. 250267-273

    Biomass energy is considered as the most potential petroleum substitute in a shorter period of time, for its renewable ability and lower pollution. This research tends to extract algae oil from microalgae with microwave fragmentation technology. This process can reduce the production costs of microalgae biodiesel. The catalysts prepared in different conditions are characterized by BET, XRD and the conversion from the transesterification catalyzed by each catalyst which was determined using GC. Microwave is used for assisting in the lipid extraction of microalgae by solvents in this study. Microwave assists in lipid extraction under various solvents, and the extracting time and power are compared. The experimental results show that microalgae extracted using the solvent has the largest extracted quantity of microalgae lipid, 30 wt.%, and the heating performance for transesterification shows that the best conversion is 76.2% under 68 degrees C with the Li4SiO4 amount 3 wt.% and the oil/methanol molar ratio 1:18 for 4 h. (C) 2014 Elsevier B.V. All rights reserved.
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  296. Subcritical water extraction of lipids from wet algae for biodiesel production
    Abstract

    Reddy, H. K.; Muppaneni, T.; Sun, Y. Q.; Li, Y.; Ponnusamy, S.; Patil, P. D.; Dailey, P.; Schaub, T.; Holguin, F. O.; Dungan, B.; Cooke, P.; Lammers, P.; Voorhies, W.; Lu, X. Y.; Deng, S. G. 2014. Subcritical water extraction of lipids from wet algae for biodiesel production. Fuel. 13373-81

    An energy efficient extraction of algal lipids from wet algal biomass was performed at subcritical conditions of water. This was achieved using microwave assisted heating as well as conventional heating. The conventional heating subcritical water (C-SCW) extraction and microwave assisted subcritical water (MW-SCW) experiments were designed and conducted to study the effects of extraction temperature, time, and biomass loading on lipid extraction. The Response surface methodology was used to optimize the parameters for maximum extraction of lipids. The influence of extraction temperature is more when compared to other experimental parameters in both processes. The maximum extraction efficiencies were achieved at 220 degrees C using conventional heating and 205 degrees C using microwave heating. Complete extraction of lipids was observed with microwave assisted heating and 70% extraction efficiency was achieved using conventional heating. The energy required for extraction is greatly reduced (2-8 folds) when compared to the conventional solvent extraction. The potential by-products like protein rich residual algae, omega-3 fatty acids, and sugars in residual water phase were identified. The biomass and the crude extracts were characterized using GC-MS, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and thermogravimetric analysis (TGA). (C) 2014 Elsevier Ltd. All rights reserved.
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  297. Sustainable Integration of Algal Biodiesel Production with Steam Electric Power Plants for Greenhouse Gas Mitigation
    Abstract

    Gutierrez-Arriaga, C. G.; Serna-Gonzalez, M.; Ponce-Ortega, J. M.; El-Halwagi, M. M. 2014. Sustainable Integration of Algal Biodiesel Production with Steam Electric Power Plants for Greenhouse Gas Mitigation. Acs Sustainable Chemistry & Engineering. 2(6) 1388-1403

    Significant reductions in anthropogenic greenhouse gas (GHG) emissions, particularly of fossil carbon dioxide (CO2), are necessary worldwide in order to prevent adverse impacts of global climate change on the socioeconomic sectors, ecological systems, and human health. In this context, this study aims to investigate the economic and environmental aspects of sustainability associated with the integration of algal biodiesel production with a steam electric power plant for microalgae biofixation of CO2 in flue gases and then algal biomass conversion to biodiesel. This integrated energy system is a multipurpose process that provides the CO2 required by the microalgae cultures as well as electricity, biodiesel produced from the algal biomass, and lipid-depleted biomass which is in turn used as an auxiliary fuel in the power plant. A multi-objective optimization strategy based on genetic algorithms is proposed to yield a set of optimal solutions providing the best compromise between the profit and the environmental impact of regenerative Rankine power generation plants coupled with algae-to-biodiesel production facilities. The power plant operates continuously, but CO2 is fed to open pond raceways only during the daytime (12 h a day) for algae growth. The rigorous IAPWS-1F97 formulation is used to calculate the thermodynamic properties of water and steam in the steam power cycle. The environmental impact is measured by the Eco-indicator 99 methodology that follows LCA principles. The optimization problem includes the selection of multiple primary energy sources for the power plant boiler, such as fossil fuels (coal, oil, and natural gas), biofuels, and biomass (switchgrass, softwood, and hardwood) in order to achieve significant reductions of CO2 emissions. The optimal trade-off designs are obtained by implementing the e-constraint method. The optimization method has been applied to a case study in Mexico. The Pareto optimal solutions indicate that the current price for biodiesel of $3.91/gal on average would make the integrated energy system under consideration profitable. In addition, the system could achieve significant environmental improvements due to life-cycle GHG reductions that result not only from biofixation of CO2 from combustion flue gases by microalgae and then algal biomass conversion and use as renewable fuels (i.e., biodiesel and lipid-depleted biomass) that substitute for fossil fuels, but also by significantly reducing the fossil fuel requirement compared to stand-alone coal-fired power plants.
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  298. The combined production of ethanol and biogas from microalgal residuals to sustain microalgal biodiesel: A theoretical evaluation
    Abstract

    Zhu, L. D. 2014. The combined production of ethanol and biogas from microalgal residuals to sustain microalgal biodiesel: A theoretical evaluation. Biofuels Bioproducts & Biorefining-Biofpr. 8(1) 7-15

    To date, researchers have expressed increasing interest in the potential of using microalgae as a biofuel feedstock and technological solution for CO2 sequestration. Microalgae-derived biodiesel production is one of the best choices for biofuels production, since microalgae have substantial amounts of lipids which can be used for biodiesel conversion. Nonetheless, after the production of algal biodiesel, large quantities of residuals or post-extracts are left over, threatening environmental hygiene if not disposed of appropriately. In this respect, it is critical that the utilization of these remnants is taken into account in an effort to make microalgal biodiesel sustainable. This paper evaluates the theoretical biodiesel, ethanol, and methane yields and the relative calorific values in the production chain of algal biofuels. It is found that fermentation and anaerobic digestion of microalgae residuals are two steps which could assist in dealing with the problem of algal waste, as well as the economic and energetic balance of such a promising technology. It also discusses in detail the potential of the continuous conversion of algal residuals into ethanol and methane, with particular focus on the energetic interest, and nitrogen and phosphorus recycling. Key technical issues related to fermentation and anaerobic digestion are indentified, the strategies to improve their production highlighted, and the necessity of producing algal biodiesel and/or ethanol discussed. (c) 2013 Society of Chemical Industry and John Wiley & Sons, Ltd
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  299. The effect of algae species on biodiesel and biogas production observed by using a data model combines algae cultivation with an anaerobic digestion (ACAD) and a biodiesel process
    Abstract

    Sapci, Z.; Morken, J. 2014. The effect of algae species on biodiesel and biogas production observed by using a data model combines algae cultivation with an anaerobic digestion (ACAD) and a biodiesel process. Energy Conversion and Management. 79519-524

    The influence of an algae species based on the biodiesel yield was investigated by using a combined plant model from the literature. The model has six different processes: algal cultivation, the flocculation and separation process, biodiesel production, anaerobic digestion, scrubbing, and combined heat and power (CHP). The data model in the literature was operated with the values for Chlorella vulgaris. To investigate the roles of the algae species on the biodiesel yield in the model, two different algae species, Nannochloropsis sp. and Haematococcus pluvialis, were selected. Depending on the data from these algae in the literature, three different scenarios were modeled in the study. The model shows that all of the scenarios for biodiesel production can be totally independent of an external energy supply. Energy estimations for all of the applications scenarios show that the system produces more energy than the amount that is required for the processing operation. (C) 2013 Elsevier Ltd. All rights reserved.
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  300. The Optimization of Biodiesel Fuel Production from Microalgae Oil Using Response Surface Methodology
    Abstract

    Makareviciene, V.; Skorupskaite, V.; Levisauskas, D.; Andruleviciute, V.; Kazancev, K. 2014. The Optimization of Biodiesel Fuel Production from Microalgae Oil Using Response Surface Methodology. International Journal of Green Energy. 11(5) 527-541

    Biodiesel fuel was produced by the transesterification of microalgae oil using sodium hydroxide as a catalyst. The oil was extracted from heterotrophic cultivated algae biomass. The transesterification process was optimized using response surface methodologyto increase the yield of methyl esters. The Box-Behnken design and fractional factorial design 2(4-1) points were used to investigate the interaction of process variables, such as the methanol/oil molar ratio, the percentage of sodium hydroxide, the temperature, and the reaction time in the production of biodiesel fuel, and to predict the optimum process conditions for the FAME yield. Based on the results, the optimal conditions for the synthesis of biodiesel fuel were as follows: methanol/oil molar ratio, 7:1; catalyst concentration, 1.0% (by weight of algae oil); temperature, 67 degrees C, and reaction time, 51 minutes. The yield of FAME was confirmed by gas chromatography analysis.
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  301. Thermo-resistant green microalgae for effective biodiesel production: Isolation and characterization of unialgal species from geothermal flora of Central Anatolia
    Abstract

    Onay, M.; Sonmez, C.; Oktem, H. A.; Yucel, A. M. 2014. Thermo-resistant green microalgae for effective biodiesel production: Isolation and characterization of unialgal species from geothermal flora of Central Anatolia. Bioresource Technology. 16962-71

    Oil content and composition, biomass productivity and adaptability to different growth conditions are important parameters in selecting a suitable microalgal strain for biodiesel production. Here, we describe isolation and characterization of three green microalgal species from geothermal flora of Central Anatolia. All three isolates, namely, Scenedesmus sp. METUNERGY1402 (Scenedesmus sp. ME02), Hindakia tetrachotoma METUNERGY1403 (H. tetrachotoma ME03) and Micractinium sp. METUNERGY1405 (Micractinium sp. ME05) are adaptable to growth at a wide temperature range (25-50 degrees C). Micractinium sp. ME05, particularly has superior properties for biodiesel production. Biomass productivity, lipid content and lipid productivity of this isolate are 0.17 g L (1) d (1), 22.7% and 0.04 g L (1) d (1), respectively. In addition, Micractinium sp. ME05 and Scenedesmus sp. ME03 mainly contain desirable fatty acid methyl esters (i.e. 16:0, 16:1, 18:0 and 18:1) for biodiesel production. All isolates can further be improved via genetic and metabolic engineering strategies. (C) 2014 Elsevier Ltd. All rights reserved.
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  302. Thermo-resistant microalgae for biodiesel production
    Abstract

    Onay, M.; Sonmez, C.; Oktem, H. A.; Yucel, M. 2014. Thermo-resistant microalgae for biodiesel production. Febs Journal. 281672-673

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  303. Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors
    Abstract

    Maroneze, M. M.; Barin, J. S.; de Menezes, C. R.; Queiroz, M. I.; Zepka, L. Q.; Jacob-Lopes, E. 2014. Treatment of cattle-slaughterhouse wastewater and the reuse of sludge for biodiesel production by microalgal heterotrophic bioreactors. Scientia Agricola. 71(6) 521-524

    Microalgal heterotrophic bioreactors are a potential technological development that can convert organic matter, nitrogen and phosphorus of wastewaters into a biomass suitable for energy production. The aim of this work was to evaluate the performance of microalgal heterotrophic bioreactors in the secondary treatment of cattle-slaughterhouse wastewater and the reuse of microalgal sludge for biodiesel production. The experiments were performed in a bubble column bioreactor using the microalgae Phormidium sp. Heterotrophic microalgal bioreactors removed 90 % of the chemical oxygen demand, 57 % of total nitrogen and 52 % of total phosphorus. Substantial microalgal sludge is produced in the process (substrate yield coefficient of 0.43 mg(sludge) mg(chemical) (-1)(oxygen demand)) resulting in a biomass with high potential for producing biodiesel (ester content of more than 99 %, cetane number of 55, iodine value of 73.5 g (lodine)100 g(-1), unsaturation degree of similar to 75 % and a cold filter plugging point of 5 degrees C).
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  304. Two-step process for production of biodiesel blends from oleaginous yeast and microalgae
    Abstract

    McCurdy, A. T.; Higham, A. J.; Morgan, M. R.; Quinn, J. C.; Seefeldt, L. C. 2014. Two-step process for production of biodiesel blends from oleaginous yeast and microalgae. Fuel. 137269-276

    Biodiesel produced from oleaginous microorganisms shows promise in displacing use of petroleum diesel fuel, however, low biodiesel yields and rigorous processing have thwarted large-scale commercialization. Here, we report a simple and efficient two-step process for generating biodiesel blends from microbial biomass, which eliminates the need for solvent extractions, distillations, or additional purifications. In the present work, diesel fuel was utilized to extract biodiesel produced from direct transesterification of the yeast, Cryptococcus curvatus, and microalgae, Scenedesmus dimorphus, thus generating a blend of microbial biodiesel and diesel fuel. Up to 93% and 83% of the produced biodiesel is extracted from both yeast and microalgae, respectively, whereas the majority of pigments are excluded. A B20 blend produced from yeast meets key ASTM fuel requirements including flash point, viscosity, sulfur, oxidation stability, and acid number. Integration of experimental data into system models reveals a 25% reduction in the net energy ratio (NER) with the process presented here compared to traditional solvent extraction. (C) 2014 Elsevier Ltd. All rights reserved.
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  305. Ultrasound-enhanced rapid in situ transesterification of marine macroalgae Enteromorpha compressa for biodiesel production
    Abstract

    Suganya, T.; Kasirajan, R.; Renganathan, S. 2014. Ultrasound-enhanced rapid in situ transesterification of marine macroalgae Enteromorpha compressa for biodiesel production. Bioresource Technology. 156283-290

    In situ transesterification of Enteromorpha compressa algal biomass was carried out for the production of biodiesel. The maximum methyl esters (ME) yield of 98.89% was obtained using ultrasonic irradiation. Tetra hydro furan (THF) and acid catalyst (H2SO4) was found to be an appropriate co-solvent and catalyst for high free fatty acids (FFA) content E. compressa biomass to increase the efficiency of the reactive in situ process. The optimization study was conducted to obtain the maximum yield and it was determined as 30 vol% of THF as a co-solvent, 10 wt% of H2SO4, 5.5:1 ratio of methanol to algal biomass and 600 rpm of mixing intensity at 65 degrees C for 90 min of ultrasonic irradiation time. The produced biodiesel was characterized by H-1 nuclear magnetic resonance spectroscopy (H-1 NMR) analysis. Kinetic studies revealed that the reaction followed the first-order reaction mechanism. Rapid in situ transesterification was found to be suitable technique to produce biodiesel from marine macroalgae feedstock. (C) 2014 Elsevier Ltd. All rights reserved.
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  306. UV-C-mediated lipid induction and settling, a step change towards economical microalgal biodiesel production
    Abstract

    Sharma, K.; Li, Y.; Schenk, P. M. 2014. UV-C-mediated lipid induction and settling, a step change towards economical microalgal biodiesel production. Green Chemistry. 16(7) 3539-3548

    Microalgae are highly efficient primary producers that can be grown in most types of water on non-arable land as a promising source of biofuel. However, large-scale microalgal biofuel production is currently uneconomical due to slow growth of high-percentage oleaginous algae and large harvesting costs. Here we present a new strategy, using a small dose of externally applied UV-C radiation, that significantly increases lipid contents of fast growing microalgae and that at higher doses also results in rapid settling. The procedure essentially separates biomass growth from lipid accumulation and harvesting which was tested in several microalgal strains and optimized to be completed within 48 h for Tetraselmis sp. using pilot-scale outdoor cultivation. This process resulted in a significant increase of both volumetric and areal lipid productivity with higher polyunsaturated fatty acid contents, while considerably reducing harvesting costs. Other benefits include control of co-cultured microbes and sanitized water for recirculation. UV-C-mediated lipid induction and settling (LIS) may contribute to commercial microalgal biofuel production.
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  307. A microalgae residue based carbon solid acid catalyst for biodiesel production
    Abstract

    Fu, X. B.; Li, D. H.; Chen, J.; Zhang, Y. M.; Huang, W. Y.; Zhu, Y.; Yang, J.; Zhang, C. W. 2013. A microalgae residue based carbon solid acid catalyst for biodiesel production. Bioresource Technology. 146767-770

    Biodiesel production from microalgae is recognized as one of the best solutions to deal with the energy crisis issues. However, after the oil extraction from the microalgae, the microalgae residue was generally discarded or burned. Here a novel carbon-based solid acid catalyst derived from microalgae residue by in situ hydrothermal partially carbonization were synthesized. The obtained catalyst was characterized and subjected to both the esterification of oleic acid and transesterification of triglyceride to produce biodiesel. The catalyst showed high catalytic activity and can be regenerated while its activity can be well maintained after five cycles. (C) 2013 Elsevier Ltd. All rights reserved.
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  308. A quantitative analysis of microalgal lipids for optimization of biodiesel and omega-3 production
    Abstract

    Olmstead, I. L.; Hill, D. R.; Dias, D. A.; Jayasinghe, N. S.; Callahan, D. L.; Kentish, S. E.; Scales, P. J.; Martin, G. J. 2013. A quantitative analysis of microalgal lipids for optimization of biodiesel and omega-3 production. Biotechnol Bioeng. 110(8) 2096-104

    The lipid characteristics of microalgae are known to differ between species and change with growth conditions. This work provides a methodology for lipid characterization that enables selection of the optimal strain, cultivation conditions, and processing pathway for commercial biodiesel production from microalgae. Two different microalgal species, Nannochloropsis sp. and Chlorella sp., were cultivated under both nitrogen replete and nitrogen depleted conditions. Lipids were extracted and fractionated into three major classes and quantified gravimetrically. The fatty acid profile of each fraction was analyzed using GC-MS. The resulting quantitative lipid data for each of the cultures is discussed in the context of biodiesel and omega-3 production. This approach illustrates how the growth conditions greatly affect the distribution of fatty acid present in the major lipid classes and therefore the suitability of the lipid extracts for biodiesel and other secondary products.
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  309. A quantitative analysis of microalgal lipids for optimization of biodiesel and omega-3 production
    Abstract

    Olmstead, I. L. D.; Hill, D. R. A.; Dias, D. A.; Jayasinghe, N. S.; Callahan, D. L.; Kentish, S. E.; Scales, P. J.; Martin, G. J. O. 2013. A quantitative analysis of microalgal lipids for optimization of biodiesel and omega-3 production. Biotechnology and Bioengineering. 110(8) 2096-2104

    The lipid characteristics of microalgae are known to differ between species and change with growth conditions. This work provides a methodology for lipid characterization that enables selection of the optimal strain, cultivation conditions, and processing pathway for commercial biodiesel production from microalgae. Two different microalgal species, Nannochloropsis sp. and Chlorella sp., were cultivated under both nitrogen replete and nitrogen depleted conditions. Lipids were extracted and fractionated into three major classes and quantified gravimetrically. The fatty acid profile of each fraction was analyzed using GC-MS. The resulting quantitative lipid data for each of the cultures is discussed in the context of biodiesel and omega-3 production. This approach illustrates how the growth conditions greatly affect the distribution of fatty acid present in the major lipid classes and therefore the suitability of the lipid extracts for biodiesel and other secondary products. Biotechnol. Bioeng. 2013; 110: 2096-2104. (c) 2013 Wiley Periodicals, Inc.
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  310. A Study of Microalgal Symbiotic Communities with the Aim to Increase Biomass and Biodiesel Production
    Abstract

    Baggesen, C.; Gjermansen, C.; Brandt, A. B. 2013. A Study of Microalgal Symbiotic Communities with the Aim to Increase Biomass and Biodiesel Production. Phycologia. 52(4) 6-6

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  311. A Techno-Economic Analysis of Biodiesel Production from Microalgae
    Abstract

    Olivieri, G.; Guida, T.; Salatino, P.; Marzocchella, A. 2013. A Techno-Economic Analysis of Biodiesel Production from Microalgae. Environmental Engineering and Management Journal. 12(8) 1563-1573

    The preliminary assessment of a cost-effective flow-sheet for the production of biodiesel from microalgae lipid fraction was carried out. The study was based on approximated cost-estimation methods integrated with the simulation software Aspen Plus (R). Several scenarios were investigated to compare costs regarding the main steps of the biodiesel production process. Ranges of input variables from downstream literature and experimental data were used to simulate the sections that define concrete process routes for production of algal biofuels: the extraction of the lipid fraction from aqueous solution, the lipid transesterification, and the methyl esters (FAMEs) and glycerol recover. The design variables were selected so as to correspond to the main degrees of freedom of the process: number of equilibrium stages, solvent recycle flow rate, transesterification time, methanol to triacylglycerols ratio, plate number and reflux ratio of the distillation unit for methanol recovery. The cost estimation for the conceptual design of the flowsheet dedicated to the FAMEs production from microalgae was carried out according to Happel's method. Data were worked out to assess the venture profit and the selling price (s) for mass unit of FAMEs. The minimization of s was adopted as the objective function. A preliminary determination of plausible values of the cost for unit of mass of biodiesel was attempted as a function of operating conditions.
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  312. Advances in cultivation and processing techniques for microalgal biodiesel: A review
    Abstract

    Xiao, M. Z.; Shin, H. J.; Dong, Q. H. 2013. Advances in cultivation and processing techniques for microalgal biodiesel: A review. Korean Journal of Chemical Engineering. 30(12) 2119-2126

    The key technologies for producing microalgal biodiesel include microalgae screening, economical cultivation, and efficient methods in lipid extraction and conversion. Recent advances in microalgae cultivation, lipid extraction, and biodiesel preparation are reviewed in this work, with emphasis on photosynthetic metabolisms, separation efficiency and catalytic kinetics. The mutual exclusion between lipid accumulation and fast growth limits total lipid productivity, while only triglycerides in neutral lipids are converted to biodiesel through transesterification. The hurdles in large scale culture and low neural lipids yield are discussed, as well as the relationship between high unsaturation and fuel properties. This review aims to provide technical information to guide strain screening and lipid conversion for microalgal biodiesel industry.
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  313. Advances in direct transesterification of microalgal biomass for biodiesel production
    Abstract

    Hidalgo, P.; Toro, C.; Ciudad, G.; Navia, R. 2013. Advances in direct transesterification of microalgal biomass for biodiesel production. Reviews in Environmental Science and Bio-Technology. 12(2) 179-199

    Microalgae biomass is becoming an interesting raw material to produce biodiesel, where several approaches in the transesterification process have been applied such as different catalysts, different acyl acceptors, incorporation of co-solvents and the different operational conditions. However there are some drawbacks that must be solved before any industrial application could be intended. The main problems are related with the high water content of the biomass (over 80 %) and the several process steps involved in biodiesel production such as: drying, cell disruption, oils extraction, transesterification and biodiesel refining. In comparison to other alternatives, the use of direct transesterification could be a suitable alternative since cell disruption, lipids extraction and transesterification are carried out in one step, with a direct reaction of oil-bearing biomass to biodiesel. This process could be applied even using biomass with high water content, and its efficiency could be improved by the incorporation of promising technologies such as microwave or ultrasonication that can enhance the mass transfer rate between immiscible phases, simultaneously diminishing the reaction time. However, it is still necessary to decrease the costs of these technologies so they can be suitable alternatives in future industrial applications.
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  314. An assessment of the economic aspects of CO2 sequestration in a route for biodiesel production from microalgae
    Abstract

    Soares, F. R.; Martins, G.; Seo, E. S. M. 2013. An assessment of the economic aspects of CO2 sequestration in a route for biodiesel production from microalgae. Environmental Technology. 34(13-14) 1777-1781

    Photosynthetic microalgae are unicellular organisms that, during their cultivation, can fix carbon dioxide efficiently from various sources, including the air and exhaust gases from industrial processes. This feature can lead to economic benefits in the production process of biodiesel by way of the clean development mechanism, for which carbon credits for environmental benefits may be granted and which will contribute towards reducing costs in the production process. This study seeks to quantify the contribution of carbon credits in the operating costs of a route for biodiesel production from microalgae, as proposed by Davis et al. [Techno-economic analysis of autotrophic microalgae for fuel production. Appl Energy. 2011;88:3524-3531]. The results showed a reduction in annual operating costs by around 5%. This figure may be conservative, since the production process considered can be further improved to reduce operating costs and thus increase the contribution margin of carbon credits, which will reduce costs. On the other hand, the price of carbon may also rise in the future, thereby increasing its contribution towards a reduction in operating costs.
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  315. Analysis of Microalgal Biorefineries for Bioenergy from an Environmental and Economic Perspective Focus on Algal Biodiesel
    Abstract

    Harrison, S. T. L.; Richardson, C.; Griffiths, M. J. 2013. Analysis of Microalgal Biorefineries for Bioenergy from an Environmental and Economic Perspective Focus on Algal Biodiesel. Biotechnological Applications of Microalgae: Biodiesel and Value-Added Products. 113-136

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  316. Biodiesel catalysts for algal oil and other low quality feedstocks
    Abstract

    Adams, D.; Chuck, C.; Davidson, M. 2013. Biodiesel catalysts for algal oil and other low quality feedstocks. Abstracts of Papers of the American Chemical Society. 246

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  317. Biodiesel from microalgae: A critical evaluation from laboratory to large scale production
    Abstract

    Rawat, I.; Kumar, R. R.; Mutanda, T.; Bux, F. 2013. Biodiesel from microalgae: A critical evaluation from laboratory to large scale production. Applied Energy. 103444-467

    The economically significant production of carbon-neutral biodiesel from microalgae has been hailed as the ultimate alternative to depleting resources of petro-diesel due to its high cellular concentration of lipids, resources and economic sustainability and overall potential advantages over other sources of biofuels. Pertinent questions however need to be answered on the commercial viability of large scale production of biodiesel from microalgae. Vital steps need to be critically analysed at each stage. Isolation of microalgae should be based on the question of whether marine or freshwater microalgae, cultures from collections or indigenous wild types are best suited for large scale production. Furthermore, the determination of initial sampling points play a pivotal role in the determination of strain selection as well as strain viability. The screening process should identify, purify and select lipid producing strains. Are natural strains or stressed strains higher in lipid productivity? The synergistic interactions that occur naturally between algae and other microorganisms cannot be ignored. A lot of literature is available on the downstream processing of microalgae but a few reports are available on the upstream processing of microalgae for biomass and lipid production for biodiesel production. We present in this review an empirical and critical analysis on the potential of translating research findings from laboratory scale trials to full scale application. The move from laboratory to large scale microalgal cultivation requires careful planning. It is imperative to do extensive pre-pilot demonstration trials and formulate a suitable trajectory for possible data extrapolation for large scale experimental designs. The pros and cons of the two widely used methods for growing microalgae by photobioreactors or open raceway ponds are discussed in detail. In addition, current methods for biomass harvesting and lipid extraction are critically evaluated. This would be novel approach to economical biodiesel production from microalgae in the near future. Globally, microalgae are largest biomass producers having higher neutral lipid content outcompeting terrestrial plants for biofuel production. However, the viscosities of microalgal oils are usually higher than that of petroleum diesel. (c) 2012 Elsevier Ltd. All rights reserved.
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  318. Biodiesel from Microalgal Oil Extraction
    Abstract

    Goncalves, A. L.; Pires, J. C. M.; Simoes, M. 2013. Biodiesel from Microalgal Oil Extraction. Green Materials for Energy, Products and Depollution. 31-25

    The rapid development of the modern society has resulted in an increased demand for energy, and consequently an increased use of fossil fuel reserves. Burning fossil fuels is nowadays one of the main threats to the environment, especially due to the accumulation of greenhouse gases in the atmosphere, which are responsible for global warming. Furthermore, the continuous use of this non-renewable source of energy will lead to an energy crisis because fossil fuels are of limited availability. In response to this energy and environmental crisis, it is of extreme importance to search for different energy supplies that are renewable and more environmentally friendly. Microalgae are a promising sustainable resource that can reduce the dependence on fossil fuel. Biodiesel production through microalgae is actually highly studied. It includes several steps, such as cell cultivation and harvesting, oil extraction and biodiesel synthesis. Although several attempts have been made to improve biodiesel yields from microalgae, further studies are required to optimize production conditions and to reduce production costs.
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  319. Biodiesel production from heterotrophic microalgae through transesterification and nanotechnology application in the production
    Abstract

    Zhang, X. L.; Van, S.; Tyagi, R. D.; Surampalli, R. Y. 2013. Biodiesel production from heterotrophic microalgae through transesterification and nanotechnology application in the production. Renewable & Sustainable Energy Reviews. 26216-223

    Vegetable oils and animal fats are the most often used feedstock in biodiesel production; however, they are also used in food production, which results in increasing the feedstock price due to the competition. Therefore, alternative feedstock is required in biodiesel production. Heterotrophic microalgae are found capable of accumulating high lipid (up to 57% w/w). They can use complex carbons such as sweet sorghum and Jerusalem artichoke as nutrients to produce equivalent quantity oil as that of using glucose, which provides a cheap biodiesel production strategy. It was found that nanomaterials could stimulate microorganism metabolism, which suggested that nanomaterial addition in the cultivation could enhance lipid production of microalgae. Furthermore, the use of nanomaterials could improve the efficiency of the lipid extraction and even accomplish it without harming the microalgae. Nanomaterials such as CaO and MgO nanoparticles have been used as biocatalyst carriers or as heterogeneous catalyst in oil transesterification to biodiesel. In this paper, the factors that could impact on lipid accumulation of heterotrophic microalgae are critically reviewed; the advances on application of nanotechnology in microalgae lipid accumulation, extraction, and transesterification are addressed. (C) 2013 Elsevier Ltd. All rights reserved.
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  320. Characterization and Application in Biocomposites of Residual Microalgal Biomass Generated in Third Generation Biodiesel
    Abstract

    Toro, C.; Reddy, M. M.; Navia, R.; Rivas, M.; Misra, M.; Mohanty, A. K. 2013. Characterization and Application in Biocomposites of Residual Microalgal Biomass Generated in Third Generation Biodiesel. Journal of Polymers and the Environment. 21(4) 944-951

    This research paper provides a brief discussion about the relevance of third generation biodiesel co-products diversification. This diversification can be performed through the utilization of residual microalgal biomass (RMB) after oil extraction process. The present work analyses the use of RMB as potential filler for biocomposite production by means of understanding the chemical composition, the thermal stability as well as the protein content of RMB. Thermogravimetric analysis revealed the processing window of the RMB for biocomposite production and its dependence on its purity, especially on residual fat content. Biocomposites of RMB and poly(butylene succinate) (PBS) were prepared by melting processing technique using extrusion followed by injection-molding. Tensile, flexural and impact properties of the processed samples were evaluated. Scanning electron microscopy of fractured sections of the biocomposites was also used to examine the dispersion of RMB in PBS matrix. Finally, this study shows a competitive alternative to produce PBS-RMB biocomposites by replacing PBS by RMB in the range between 20 and 30 %. However, further studies are necessary to improve the compatibility of RMB with PBS to obtain competitive mechanical properties, compared to neat materials through, for instance, block co-polymers.
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  321. Chromatographic characterization of triacylglycerides and fatty acid methyl esters in microalgae oils for biodiesel production
    Abstract

    Soares, A. T.; Silva, B. F.; Fialho, L. L.; Pequeno, M. A. G.; Vieira, A. A. H.; Souza, A. G.; Antoniosi, N. R. 2013. Chromatographic characterization of triacylglycerides and fatty acid methyl esters in microalgae oils for biodiesel production. Journal of Renewable and Sustainable Energy. 5(5)

    The fatty acid methyl ester and triacylglyceride content of the oils of seven microalgae species were analyzed by gas chromatography in order to predict the influence of fatty acid content on the physicochemical properties of biodiesel. Among the seven species examined, Chlorella minutissima and Arthrospira platensis showed biodiesel production potential, while fatty acids from Chlorella vulgaris, Cyclotella sp., Cylindrotheca closterium, Entomoneis alata, and A. platensis have great economic values, with application in the pharmaceutical and food industries. The oxidative stability of the biodiesel produced from C. minutissima will be high, but there will be problems with cold filter plugging point temperatures. These can be solved by mixing C. minutissima biodiesel with a biodiesel like that from Ankistrodesmus gracilis that is rich in di- or tri-unsaturated fatty acids. Triacylglyceride analysis made it possible to tell if a microalgae oil is composed mainly of triacylglycerides or of some other class of lipids. (C) 2013 AIP Publishing LLC.
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  322. Comments on a Method for Estimating Cloud Point and Cold Filter Plugging Point of Microalgal Oil Fatty Acid Methyl Esters
    Abstract

    Iyer, R. 2013. Comments on a Method for Estimating Cloud Point and Cold Filter Plugging Point of Microalgal Oil Fatty Acid Methyl Esters. Journal of the American Oil Chemists Society. 90(10) 1569-1576

    Cloud points (CPs) of five vegetable oil fatty acid methyl esters (FAME) and three biodiesel mixtures estimated by a thermodynamic equation were compared to measured CPs. The results indicate that estimated CP of peanut oil FAME are similar to measured CP and for three biodiesel mixtures a minimum total saturated FAME (SFAME) concentration is required for measured CPs to be closer to estimated CPs. These comparisons provide the basis for comments on using this method for estimating CPs of 22 test data of microalgae FAME. Cold filter plugging points (CFPPs) calculated by equation CFPP = 1.0191 x CP - 2.9 with CPs verified from the thermodynamic equation was found to be identical to CFPPs reported in literature for 22 test data of microalgae FAME. Therefore these CPs were inserted in equation CFPP = CP -4.5 for another set of CFPPs. Plots of CFPPs versus percent SFAME of the 22 test data of microalgae FAME (> 12 %) for these two equations indicates that CFPP is controlled by 85 % of SFAME. Calculated CFPPs of vegetable oil FAME and biodiesel mixtures using both equations for estimated and measured CPs is discussed. Low concentrations of long chain saturated FAME impacting the estimation of CPs of vegetable oil FAME is used as a rationale to discuss the role of unidentified other species (OS) in estimation of CPs of microalgae FAME.
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  323. Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production
    Abstract

    Mandal, S.; Patnaik, R.; Singh, A. K.; Mallick, N. 2013. Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production. Environmental Technology. 34(13-14) 2009-2018

    Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pre-treatments of biomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4 h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.
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  324. Comparison of Algal Biodiesel Production Pathways Using Life Cycle Assessment Tool
    Abstract

    Singh, A.; Olsen, S. I. 2013. Comparison of Algal Biodiesel Production Pathways Using Life Cycle Assessment Tool. Life Cycle Assessment of Renewable Energy Sources. 145-168

    The consideration of algal biomass in biodiesel production increased very rapidly in the last decade. A life cycle assessment (LCA) study is presented to compare six different biodiesel production pathways (three different harvesting techniques, i.e., aluminum as flocculent, lime flocculent, and centrifugation, and two different oil extraction methods, i.e., supercritical CO2 (sCO(2)) and press and co-solvent extraction). The cultivation of Nannochloropsis sp. considered in a flat-panel photobioreactor (FPPBR). These algal biodiesel production systems were compared with the conventional diesel in a EURO 5 passenger car used for transport purpose (functional unit 1 person km (pkm). The algal biodiesel production systems provide lesser impact (22-105 %) in comparison with conventional diesel. Impacts of algal biodiesel on climate change were far better than conventional diesel, but impacts on human health, ecosystem quality, and resources were higher than the conventional diesel. This study recommends more practical data at pilot-scale production plant with maximum utilization of byproducts generated during the production to produce a sustainable algal biodiesel.
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  325. Direct Biodiesel Production from Wet Microalgae Biomass of Chlorella pyrenoidosa through In Situ Transesterification
    Abstract

    Cao, H. C.; Zhang, Z. L.; Wu, X. W.; Miao, X. L. 2013. Direct Biodiesel Production from Wet Microalgae Biomass of Chlorella pyrenoidosa through In Situ Transesterification. Biomed Research International.

    A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90 degrees C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% as water content increased from 0% to 90%. Higher temperature could compensate the negative effect. When temperature reached 150 degrees C, there was no negative effect, and biodiesel yield was over 100%. Based on the above research, wet microalgae biomass was directly applied to biodiesel production, and the optimal conditions were investigated. Under the optimal conditions of 100 mg dry weight equivalent wet microalgae biomass, 4 mL methanol, 8 mL n-hexane, 0.5 M H2SO4, 120 degrees C, and 180 min reaction time, the biodiesel yield reached as high as 92.5% and the FAME content was 93.2%. The results suggested that biodiesel could be effectively produced directly from wet microalgae biomass and this effort may offer the benefits of energy requirements for biodiesel production.
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  326. Effect of growth phase on harvesting characteristics, autoflocculation and lipid content of Ettlia texensis for microalgal biodiesel production
    Abstract

    Salim, S.; Shi, Z.; Vermue, M. H.; Wijffels, R. H. 2013. Effect of growth phase on harvesting characteristics, autoflocculation and lipid content of Ettlia texensis for microalgal biodiesel production. Bioresource Technology. 138214-221

    The effect of growth phase on the recovery of the autoflocculating microalgae Ettlia texensis was studied. In the stationary phase, 90% recovery was achieved after 3 h settling. Scanning electron microscopic pictures revealed that extracellular polymeric substances (EPS) on the cell surface were involved in autoflocculation. During the stationary phase an increase of the protein fraction in the EPS was observed while the total fatty acids content increased. The autoflocculating properties of E. texensis combined with favourite fatty acid content and composition make this microalgae an excellent candidate for biodiesel production if harvested at the end of the stationary phase. (c) 2013 Elsevier Ltd. All rights reserved.
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  327. Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst
    Abstract

    Tran, Dang-Thuan; Chen, C. L.; Chang, J. S. 2013. Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst. Bioresource Technology. 135213-221

    In this work, a one-step extraction/transesterification process was developed to directly convert wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 into biodiesel using immobilized Burkholderia lipase as the catalyst. The microalgal biomass (water content of 86-91%; oil content 14-63%) was pretreated by sonication to disrupt the cell walls and then directly mixed with methanol and solvent to carry out the enzymatic transesterification. Addition of a sufficient amount of solvent (hexane is most preferable) is required for the direct transesterification of wet microalgal biomass, as a hexane-to-methanol mass ratio of 1.65 was found optimal for the biodiesel conversion. The amount of methanol and hexane required for the direct transesterification process was also found to correlate with the lipid content of the microalga. The biodiesel synthesis process was more efficient and economic when the lipid content of the microalgal biomass was higher. Therefore, using high-lipid-content microalgae as feedstock appears to be desirable. (C) 2012 Elsevier Ltd. All rights reserved.
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  328. Effect of Various Catalysts on Biodiesel Production from Biomass of Freshwater Algae
    Abstract

    Ahmad, F.; Khan, A. U.; Yasar, A. 2013. Effect of Various Catalysts on Biodiesel Production from Biomass of Freshwater Algae. Asian Journal of Chemistry. 25(8) 4624-4628

    Catalyst selection for transesterification of oil to biodiesel depends on composition of oil and its source. Algal biomass is a cheaper and effective source for this purpose. Chlorella vulgaris, Rhizoclonium hieroglyphicum and mixed algae culture (Microspora sp., Navicula sp., Lyngbya sp., Cladophora sp., Spirogyra sp and Rhizoclonium sp.) were selected for current study. Several variables such as solvent types (acetone, hexane and methanol), extraction time (60-300min), molar ration (1:1, 3:1 and 6:1), catalyst types (Na, NaOH, KOH and H2SO4), catalyst concentration (0.5, 1.0 and 1.5%) and transesterification reaction time (20-100 min) were used for extraction of oil and biodiesel production. Highest quantity of oil was extracted using hexane as a solvent while highest biodiesel yield (93.93%) was obtained from transesterification of Chlorella vulgaris oil under 3;1 alcohol to oil molar ration, Na catalyst (1%) and 1 h of reaction time. The work investigated that biodiesel properties are comparable to ASTM standards hence it can be used as vehicular fuel.
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  329. Effects of Drying and Storage on Year-Round Production of Butanol and Biodiesel from Algal Carbohydrates and Lipids using Algae from Water Remediation
    Abstract

    Jernigan, A.; May, M.; Potts, T.; Rodgers, B.; Hestekin, J.; May, P. I.; McLaughlin, J.; Beitle, R. R.; Hestekin, C. 2013. Effects of Drying and Storage on Year-Round Production of Butanol and Biodiesel from Algal Carbohydrates and Lipids using Algae from Water Remediation. Environmental Progress & Sustainable Energy. 32(4) 1013-1022

    Algae harvested from a pilot water quality improvement technology at the Rockaway Wastewater Treatment Facility in New York were examined as a source of carbohydrates and lipids for the production of biofuels. Dried stocks of algae harvested during a 6-month period were used to feed the bioreactors, and the process to extract sugar from the natural wastewater grown algae was optimized. The length of storage time, storage conditions, sugar extraction process, and fuel production were studied. The results show that if the algae is stored dry (<25% moisture) the algae stock can be used for up to a year with good conversion of carbohydrates to sugars using a 10% w/v of dried algae. These optimized conditions extracted the maximum amount of sugar, which yielded an average of 0.11 (g butanol/g sugar) from the bioreactors year-round from a wide range of diatoms and other microalgae used to treat wastewater. Similarly, lipids could be obtained from the stored algal with value of >0.015 g/g algae even after a year in storage. These results demonstrate the potential for year round production of fuel from algae harvested as part of a water reclamation process. (c) 2013 American Institute of Chemical Engineers Environ Prog, 32: 1013-1022, 2013
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  330. Energetic optimization of microalgal cultivation in photobioreactors for biodiesel production
    Abstract

    Arudchelvam, Y.; Nirmalakhandan, N. 2013. Energetic optimization of microalgal cultivation in photobioreactors for biodiesel production. Renewable Energy. 5677-84

    Traditionally, algal cultivation in sparged photobioreactors has been optimized to maximize biomass productivity. In this study, an energy-based methodology is presented to maximize the net energy gain of the cultivation process by minimizing the energy input for sparging and by maximizing the energy output. Options for minimizing energy input through optimal gas-to-culture volume ratio and CO2-air ratio and options for maximizing lipid production through optimal levels of nutrition and CO2 are presented and validated with results from 900-mL bubble column reactors. In contrast to the traditional practice, the proposed energy-based optimization resulted in positive net energy gains. In single stage approach under optimal conditions (CO2 enrichment of 0.5%, gas-to-culture volume ratio of 0.18 min(-1), and nitrate level of 1 mM), tests with Nannochloropsis sauna resulted in positive net energy gain of 20 W/m(3). In a test under nitrate starvation, the net energy gain in a reactor sparged with CO2 enrichment of 0.5% was double that in the reactor sparged with ambient air (8 vs. 19 W/m(3)). (C) 2012 Elsevier Ltd. All rights reserved.
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  331. Engineering challenges in biodiesel production from microalgae
    Abstract

    Aguirre, A. M.; Bassi, A.; Saxena, P. 2013. Engineering challenges in biodiesel production from microalgae. Critical Reviews in Biotechnology. 33(3) 293-308

    In recent years, the not too distant exhaustion of fossil fuels is becoming apparent. Apart from this, the combustion of fossil fuels leads to environmental concerns, the emission of greenhouse gases and issues with global warming and health problems. Production of biodiesel from microalgae may represent an attractive solution to the above mentioned problems, and can offer a renewable source of fuel with fewer pollutants. This review presents a compilation of engineering challenges related to microalgae as a source of biodiesel. Advantages and current limitations for biodiesel production are discussed; some aspects of algae cells biology, with emphasis on cell wall composition, as it represents a barrier for fatty acid extraction and lipid droplets are also presented. In addition, recent advances in the different stages of the manufacturing process are included, starting from the strain selection and finishing in the processing of fatty acids into biodiesel.
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  332. Environmental Assessment of Microalgae Biodiesel Production in Colombia: Comparison of Three Oil Extraction Systems
    Abstract

    Pardo-Cardenas, Y.; Herrera-Orozco, I.; Gonzalez-Delgado, A. D.; Kafarov, V. 2013. Environmental Assessment of Microalgae Biodiesel Production in Colombia: Comparison of Three Oil Extraction Systems. Ct&F-Ciencia Tecnologia Y Futuro. 5(2) 85-100

    The objective of the study was to compare three cases of biodiesel production from microalgae dried biomass applying the Life Cycle Assessment (LCA) technique by means of the "cradle to grave" concept, presenting preliminary results for environmental assessment of emerging technologies for microalgae biodiesel production in Colombia focused on oil extraction stage. The evaluated processes correspond to the following cases: case 1 hexane-based extraction (HE), case 2 methanol/chloroform (MCE) and case 3 ethanol/hexane (EHE). Operating conditions for each extraction method were adjusted with experimental work. Routes were simulated using the Aspen Plus (R) 7.1 software, taking as a feedstock a robust modeled composition of Chlorella sp. Environmental emissions associated with algae biodiesel production were quantified and-evaluated through the Simapro 7.1 software. The outcomes confirm the potential of microalgae as a sink of greenhouses gases, but highlight the crucial necessity of decreasing energy consumption and some technical improvements in oil extraction step. Results related with greenhouse gas (GHG) emissions were compared with European sustainability criteria, in order to identify the reduction of the hypothetical microalgae biodiesel. Case 1 presents the most important reduction respect to fossil reference (156%). For the other two scenarios, reduction decreases because of higher energy consumption. Case 2 presents a reduction of approximately 99% and case 3 presents a reduction reaching 14%.
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  333. Evaluating new isolates of microalgae from Kazakhstan for biodiesel production
    Abstract

    Dyo, Y. M.; Vonlanthen, S. E.; Purton, S.; Zayadan, B. K. 2013. Evaluating new isolates of microalgae from Kazakhstan for biodiesel production. Russian Journal of Plant Physiology. 60(4) 549-554

    New microalgal strains that are native to South-East Kazakhstan were isolated and characterized with a view to identifying suitable candidates for biodiesel production. Six strains of chlorophyte algae (named K1-K6) were recovered from environmental samples as axenic cultures, and molecular analysis revealed that five (K1-K5) are strains of Parachlorella kessleri, whereas K6 is a strain of Chlorella vulgaris. A third isolate from Uzbekistan (termed UZ) was also identified as a separate strain of P. kessleri. All strains show high growth rates and an ability to utilize acetate as an exogenous source of fixed carbon. Furthermore, under conditions of nitrogen depletion, all three strains showed a significant accumulation of neutral lipids (triacylglycerides). P. kessleri K5 and C. vulgaris K6 therefore represent promising autochthon strains for large-scale cultivation and biodiesel production in Kazakhstan.
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  334. Evaluation of the potential of 10 microalgal strains for biodiesel production
    Abstract

    Song, M. M.; Pei, H. Y.; Hu, W. R.; Ma, G. X. 2013. Evaluation of the potential of 10 microalgal strains for biodiesel production. Bioresource Technology. 141245-251

    In this study, the potential of 10 algae species for biodiesel production were evaluated by determining their fatty acid profiles, biodiesel properties besides growth rate, biomass concentration and lipid productivity. Among seven strains with high growth and lipid accumulation properties, excluding Kirchneriella lunaris and Lyngbya kuetzingii, five species Selenastrum capricornutum, Chlorella vulgaris, Scenedesmus obliqnus, Phaeodactylum tricornutum and Isochtysis sphacrica were finally selected for biodiesel production due to their possessing higher lipid productivity and favorable biodiesel properties. The best strain was P. tricornutum, with lipid content of 61.43 +/- 0.95%, lipid productivity of 26.75 mg L-1 d(-1), the favorable fatty acid profiles of C16-C18 (74.50%), C14:0 (11.68%) and C16:1 (22.34%) as well as suitable biodiesel properties of higher cetane number (55.10), lower iodine number (99.2 gI(2)/100 g) and relatively low cloud point (4.47 degrees C). (c) 2013 Elsevier Ltd. All rights reserved.
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  335. Evaluation of the Potentiality of Freshwater Microalgae as a Source of Raw Material for Biodiesel Production
    Abstract

    Menezes, R. S.; Leles, M. I. G.; Soares, A. T.; Franco, P. I. B. E. M.; Antoniosi, N. R.; Sant'Anna, C. L.; Vieira, A. A. H. 2013. Evaluation of the Potentiality of Freshwater Microalgae as a Source of Raw Material for Biodiesel Production. Quimica Nova. 36(1) 10-15

    EVALUATION OF THE POTENTIALITY OF FRESHWATER MICROALGAE AS A SOURCE OF RAW MATERIAL FOR BIODIESEL PRODUCTION. In this work, the fatty acid quantity and composition of six freshwater microalgae and soybean grains was determined by direct transesterification and gas chromatography analysis. The results showed that all the freshwater microalgae species presented a higher quantity of fatty acid than soybean grain. Choricystis sp. (A) provides 115% more fatty acids per gram of biomass than soybean grain. With regard to the fatty acid composition, Choricystis sp. (A) showed an adequate proportion of saturated and unsaturated fatty acids, with lower quantity of polyunsaturated fatty acids and, akin to some marine microalgae, constitutes an alternative raw material for biodiesel production.
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  336. Exploring Biodiesel: Chemistry, Biochemistry, and Microalgal Source
    Abstract

    Gaurav, K.; Srivastava, R.; Singh, R. 2013. Exploring Biodiesel: Chemistry, Biochemistry, and Microalgal Source. International Journal of Green Energy. 10(8) 775-796

    Because of the world energy crisis, many countries have initiated a series of measures to resolve this problem through alternative energy resources. Biodiesel as an alternate fuel has received much attention in recent years. A number of reports are available on the production of biodiesel from vegetable oils and related sources but its production from microalgae is a highly prospective field. Microalgae can produce and accumulate lipids within their cells. These lipids on transesterification yields biodiesel. Hence, microalgae have the capacity to produce more biodiesel per acre land than any other plants or living organisms. This manuscript deals with chemical and biochemical aspects of microalgae-based biodiesel and methodology of its production.
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  337. Extractive-transesterification of algal biomass into biodiesel under supercritical methanol and microwave conditions
    Abstract

    Gude, V. G.; Patil, P.; Deng, S. G. 2013. Extractive-transesterification of algal biomass into biodiesel under supercritical methanol and microwave conditions. Abstracts of Papers of the American Chemical Society. 245

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  338. Fatty acids profiling: A selective criterion for screening microalgae strains for biodiesel production
    Abstract

    Talebi, A. F.; Mohtashami, S. K.; Tabatabaei, M.; Tohidfar, M.; Bagheri, A.; Zeinalabedini, M.; Mirzaei, H. H.; Mirzajanzadeh, M.; Shafaroudi, S. M.; Bakhtiari, S. 2013. Fatty acids profiling: A selective criterion for screening microalgae strains for biodiesel production. Algal Research-Biomass Biofuels and Bioproducts. 2(3) 258-267

    The type and amount of lipids produced by an algal species directly influence the quality of the achieved biodiesel. This study is the first to report on the isolation process and lipid profile analysis of algal strains obtained from the Persian Gulf as well as 9 previously introduced strains. Biomass productivity and lipid productivity seemed to be adequate criteria for estimating the potential of different microalgae species for producing biodiesel. A principal component analysis (PCA) was applied to the estimated properties of biodiesel and the results obtained were plotted against lipid productivity. This led to the distinction of five different microalgae groups in regard to their potential for biodiesel production. This analysis also highlighted the dependence of the fuel properties on oil saturation level. On that basis, Amphora sp. and the two locally isolated strains (Dunaliella sp.) formed the extreme groups. The other three groups generated biodiesel of intermediate quality. The highest volumetric lipid productivity (79.08 mg l(-1)day(-1)) was found in Chlorella vulgaris. Based on the results of bioprospection by FAME profiling, the best approach for obtaining quality algal biodiesel is to mix the oils of distinct cell cultures or to specifically select proper microalgal strains for different climate conditions. (C) 2013 Elsevier B. V. All rights reserved.
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  339. Feasibility of biodiesel production by microalgae Chlorella sp (FACHB-1748) under outdoor conditions
    Abstract

    Zhou, X. P.; Xia, L.; Ge, H. M.; Zhang, D. L.; Hu, C. X. 2013. Feasibility of biodiesel production by microalgae Chlorella sp (FACHB-1748) under outdoor conditions. Bioresource Technology. 138131-135

    Chlorella sp. (FACHB-1748) was cultivated outdoors under natural sunlight to evaluate its potential for biofuel production. Urea was selected as nitrogen source, and the concentration was optimized. When the culture reached the late exponential stage, a triggering lipid accumulation test was conducted using different concentrations of sodium chloride and acetate. A scaling-up experiment was also conducted in a 70 L photobioreactor. The highest biomass productivity (222.42, 154.48 mg/L/d) and lipid productivity (64.30, 33.69 mg/L/d) were obtained with 0.1 g/L urea in 5 and 70 L bioreactors, respectively. The highest lipid content (43.25%) and lipid yield (1243.98 mg/L) were acquired with the combination of 10 g/L sodium chloride and acetate. Moreover, the qualities of biodiesel, cetane number, saponification value, iodine value, and cold filter plugging point complied with the standards set by the National Petroleum Agency (ANP255), Standard ASTMD6751, and European Standard (EN 14214). (C) 2013 Elsevier Ltd. All rights reserved.
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  340. Global Future Prospects and Problems of Microbial Biofuel : Algal Biodiesel
    Abstract

    Bhatnagar, S. K.; Sengar, R. S.; Singh, A.; Sengar, K. 2013. Global Future Prospects and Problems of Microbial Biofuel : Algal Biodiesel. Vegetos. 2650-55

    Human population explosion, progressive industrialization, automobiles and world energy requirements, particularly for the fossil fuel is likely to deplete limited natural resources over short period of time. Therefore, search for an alternative fuel resource is the only way to overcome the upcoming energy crisis. Biofuel, in this context seems to be a sustainable option. Biomasses so far used for biodiesel production include animal fats, vegetable oils like soybean, rapeseed, Jatropha, mahua, mustard, flax, sunflower, palm, hemp, field pennycress, Pongamia pinnata etc. which require agricultural land for their growth. In the present context, population explosion does not permit the use agricultural land for the cultivation of petro crops and therefore the scientists have to find an energy feedstock which does not require fertile land use. Keeping it in view, emphasis has been given to the autotrophic tiny organisms of algae for biodiesel production, the world over. Certain algal species contains oil producing substrate and are rapidly growing under normal conditions. This algal fat can be processed into biodiesel by trans esterification. Biodiesel production from algae involves identification of high fatty acid storing algal species, their cultivation in open or hybrid photobioreactors, harvesting, oil extraction and process standardization. Biodiesel production from algae had been emphasized by Bhatnagar et al. (2011) which need proper initiative to become energy sustainable.
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  341. Identification of naturally isolated Southern Louisiana's algal strains and the effect of higher CO2 content on fatty acid profiles for biodiesel production
    Abstract

    Moreno, R.; Aita, G. M.; Madsen, L.; Gutierrez, D. L.; Yao, S. M.; Hurlburt, B.; Brashear, S. 2013. Identification of naturally isolated Southern Louisiana's algal strains and the effect of higher CO2 content on fatty acid profiles for biodiesel production. Journal of Chemical Technology and Biotechnology. 88(5) 948-957

    BACKGROUND: Microalgae, with both high biomass productivity and oil content, are regarded as attractive candidates for the production of alternative biodiesel as well as for CO2 biofixation. In the present study, four microalgal strains native to southeastern Louisiana's waters were isolated and identified to evaluate their potential for the production of biodiesel. Selected strains were identified through genomic DNA in sequencing of either 16S rRNA or 18S rRNA genes followed by lipid and fatty acid content characterization and quantification. RESULTS: High correlation was found with known nucleotide sequence identities at 98% with Sellaphora pupula, and 99% with Synechococcus sp., Chlorella sorokiniana, Scenedesmus abundans, and Chlorella vulgaris (control). The fatty acid profiles of these organisms changed when using 5% CO2 aeration. Total fatty acids (TFA) decreased from 20.63 to 17.62, 54.83 to 24.4, and 29.82 to 23.99 g kg1 in Synechococcus sp., Sellaphora pupula and Chlorella sorokiniana, respectively. TFA increased from 14.14 to 31.49 and 15.14 to 47.52 g kg1 dry biomass in Scenedesmus abundans and Chlorella vulgaris (control), respectively. CONCLUSION: Chlorella sorokiniana, with a lower C18:3 and the highest biomass yield at 5% CO2 aeration, was found to be the best candidate for biodiesel production. (c) 2012 Society of Chemical Industry
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  342. Integration process of biodiesel production from filamentous oleaginous microalgae Tribonema minus
    Abstract

    Wang, H.; Gao, L. L.; Chen, L.; Guo, F. J.; Liu, T. Z. 2013. Integration process of biodiesel production from filamentous oleaginous microalgae Tribonema minus. Bioresource Technology. 14239-44

    Biodiesel production from microalgae has been receiving considerable attention. Past studies mainly relied on tiny sized single-cell oleaginous microalgal species, the biodiesel based on filamentous oleaginous microalgae was rarely reported. Thus, integrated process of biodiesel production from filamentous oleaginous microalgal strain Tribonema minus was studied in this work. The filamentous microalgae was cultivated for 21 days in 40 L glass panel, microalgae cells was harvested by DAF without any flocculants after the lipid content was 50.23%. After that, total lipid was extracted by subcritical ethanol from wet algal paste and 44.55% of crude lipid was triacylglycerols. Two-step catalytic conversion of pre-esterification and transesterification was adopted to convert the crude algal oil to biodiesel. The conversion rate of triacylglycerols reached 96.52% under the methanol to oil molar ratio of 12:1 during catalysis with 2% potassium hydroxide at 65 degrees C for 30 min. The biodiesel product from T. minus conformed to Chinese National Standards. (C) 2013 Elsevier Ltd. All rights reserved.
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  343. Life Cycle Energy and Carbon Footprints of Microalgal Biodiesel Production in Western Australia: A Comparison of Byproducts Utilization Strategies
    Abstract

    Gao, X. P.; Yu, Y.; Wu, H. W. 2013. Life Cycle Energy and Carbon Footprints of Microalgal Biodiesel Production in Western Australia: A Comparison of Byproducts Utilization Strategies. Acs Sustainable Chemistry & Engineering. 1(11) 1371-1380

    This study compares the performances of anaerobic digestion and hydrothermal liquefaction as by-products (defatted microalgae and glycerol) utilization strategies to offset overall life cycle energy and carbon footprints of microalgal biodiesel production in Western Australian (WA). Utilization of byproducts via anaerobic digestion or hydrothermal liquefaction enables the production of electricity and process heat, as well as the recovery of inherent nutrients. As a result, the anaerobic digestion route and hydrothermal liquefaction route substantially reduce life cycle energy inputs for producing 1 MJ biodiesel from 4.3 MJ (without byproducts utilization) to 1.3 and 0.7 MJ, yielding carbon footprints of similar to 80 and similar to 33 g CO2-eq/MJ biodiesel, respectively. The results indicate that hydrothermal liquefaction, which shows better life cycle performance and requires smaller reactor footprint than anaerobic digestion, can be another potential strategy to recover energy embedded in defatted microalgae. It is also evident that while vast coastal areas are available in WA for marine microalgae cultivation, further technological advances are required to realize a truly sustainable biodiesel production from microalgae. Sensitivity analyses suggest that key R&D areas are improvement of microalgae biological properties (e.g., growth rate and lipid content) and innovations in engineering designs (e.g., culture circulation velocity, methane yield during anaerobic digestion, and bio-oil yield during hydrothermal liquefaction).
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  344. Lipid and total fatty acid productivity in photoautotrophic fresh water microalgae: screening studies towards biodiesel production
    Abstract

    Abomohra, A.; Wagner, M.; El-Sheekh, M.; Hanelt, D. 2013. Lipid and total fatty acid productivity in photoautotrophic fresh water microalgae: screening studies towards biodiesel production. Journal of Applied Phycology. 25(4) 931-936

    Microalgae are considered as a promising feedstock for biomass production. The selection of the most suitable species is based on several key parameters such as lipid and fatty acid productivity. In the present study, the growth of different microalgae strains was examined in freshwater media for photoautotrophs suited for large-scale applications to identify the most suitable medium for each species. In the optimal medium, Scenedesmus obliquus showed the highest biomass productivity measured as increase of cell dry weight (0.25 g cellu dry weight (CDW) L-1 day(-1)), while Botryococcus braunii showed the highest lipid and total fatty acid content (430 and 270 mg g(-1) CDW, respectively) among the tested species. Regarding lipid and total fatty acid productivity, S. obliquus was the most lipid and total fatty acid productive strain with 41 and 18 mg L-1 day(-1) during the exponential phase, respectively. Additionally, the proportion of saturated and monounsaturated fatty acids increased with duration of the incubation in S. obliquus, while polyunsaturated fatty acids decreased. These results nominate S. obliquus as a promising microalga in order to serve as a feedstock for renewable energy production.
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  345. Lipid extraction methods from microalgal biomass harvested by two different paths: Screening studies toward biodiesel production
    Abstract

    Rios, S. D.; Castaneda, J.; Torras, C.; Farriol, X.; Salvado, J. 2013. Lipid extraction methods from microalgal biomass harvested by two different paths: Screening studies toward biodiesel production. Bioresource Technology. 133378-388

    Microalgae can grow rapidly and capture CO2 from the atmosphere to convert it into complex organic molecules such as lipids (biodiesel feedstock). High scale economically feasible microalgae based oil depends on optimizing the entire process production. This process can be divided in three very different but directly related steps (production, concentration, lipid extraction and transesterification). The aim of this study is to identify the best method of lipid extraction to undergo the potentiality of some microalgal biomass obtained from two different harvesting paths. The first path used all physicals concentration steps, and the second path was a combination of chemical and physical concentration steps. Three microalgae species were tested: Phaeodactylum tricornutum, Nannochloropsis gaditana, and Chaetoceros calcitrans One step lipid extraction-transesterification reached the same fatty acid methyl ester yield as the Bligh and Dyer and soxhlet extraction with n-hexane methods with the corresponding time, cost and solvent saving. (C) 2013 Elsevier Ltd. All rights reserved.
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  346. Low solvent, low temperature method for extracting biodiesel lipids from concentrated microalgal biomass
    Abstract

    Olmstead, I. L. D.; Kentish, S. E.; Scales, P. J.; Martin, G. J. O. 2013. Low solvent, low temperature method for extracting biodiesel lipids from concentrated microalgal biomass. Bioresource Technology. 148615-619

    An industrially relevant method for disrupting microalgal cells and preferentially extracting neutral lipids for large-scale biodiesel production was demonstrated on pastes (20-25% solids) of Nannochloropsis sp. The highly resistant Nannochloropsis sp. cells. were disrupted by incubation for 15 h at 37 degrees C followed by high pressure homogenization at 1200 +/- 100 bar. Lipid extraction was performed by twice contacting concentrated algal paste with minimal hexane (solvent:biomass ratios (w/w) of <2:1 and <1.3:1) in a stirred vessel at 35 degrees C. Cell disruption prior to extraction increased lipid recovery 100-fold, with yields of 30-50% w/w obtained in the first hexane contact, and a further 6.5-20% in the second contact. The hexane preferentially extracted neutral lipids over glyco- and phospholipids, with up to 86% w/w of the neutral lipids recovered. The process was effective on wet concentrated paste, required minimal solvent and moderate temperature, and did not require difficult to recover polar solvents. (C) 2013 Elsevier Ltd. All rights reserved.
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  347. Marine microalgae selection and culture conditions optimization for biodiesel production
    Abstract

    San Pedro, A.; Gonzalez-Lopez, C. V.; Acien, F. G.; Molina-Grima, E. 2013. Marine microalgae selection and culture conditions optimization for biodiesel production. Bioresource Technology. 134353-361

    Continuous cultures of Nannochloropsis gaditana, Tetraselmis chuii, Tetraselmis suecica and Phaeodactylum tricornutum were carried out at different dilution rates and culture media in order to check their influence on biomass productivity. N. gaditana attained maximum biomass productivity of 0.49 g/l day at a dilution rate of 0.42 1/day. The influence of nitrate concentration on biomass productivity was tested by continuous cultures of N. gaditana. At 8.0 mM nitrate and dilution rates ranging between 0.30 and 0.40 1/day, maximum biomass productivities were achieved. To enhance lipid accumulation, a two-stage culture strategy consisting in a first stage of nitrate-replete conditions followed by a nitrate-depleted phase was performed. The accumulated productivity was 51 mg(FATTY ACIDS)/1 day. Results showed an important change in the fatty acids profile and an increase in the neutral lipids content, representing 73.1% of total lipids. Additionally, the combination of nitrogen depletion and light stress was proved to contribute to lipid enhancement. (C) 2013 Elsevier Ltd. All rights reserved.
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  348. Methods of downstream processing for the production of biodiesel from microalgae
    Abstract

    Kim, J.; Yoo, G.; Lee, H.; Lim, J.; Kim, K.; Kim, C. W.; Park, M. S.; Yang, J. W. 2013. Methods of downstream processing for the production of biodiesel from microalgae. Biotechnology Advances. 31(6) 862-876

    Despite receiving increasing attention during the last few decades, the production of microalgal biofuels is not yet sufficiently cost-effective to compete with that of petroleum-based conventional fuels. Among the steps required for the production of microalgal biofuels, the harvest of the microalgal biomass and the extraction of lipids from microalgae are two of the most expensive. In this review article, we surveyed a substantial amount of previous work in microalgal harvesting and lipid extraction to highlight recent progress in these areas. We also discuss new developments in the biodiesel conversion technology due to the importance of the connectivity of this step with the lipid extraction process. Furthermore, we propose possible future directions for technological or process improvements that will directly affect the final production costs of microalgal biomass-based biofuels. (C) 2013 Elsevier Inc. All rights reserved.
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  349. Microalgae-based biodiesel: A multicriteria analysis of the production process using realistic scenarios
    Abstract

    Torres, C. M.; Rios, S. D.; Torras, C.; Salvado, J.; Mateo-Sanz, J. M.; Jimenez, L. 2013. Microalgae-based biodiesel: A multicriteria analysis of the production process using realistic scenarios. Bioresource Technology. 1477-16

    Microalgae-based biodiesel has several benefits over other resources such as less land use, potential cultivation in non-fertile locations, faster growth and especially a high lipid-to-biodiesel yield. Nevertheless, the environmental and economic behavior for high scale production depends on several variables that must be addressed in the scale-up procedure. In this sense, rigorous modeling and multicriteria evaluation are performed in order to achieve optimal topology for third generation biodiesel production. Different scenarios and the most promising technologies tested at pilot scale are assessed. Besides, the sensitivity analysis allows the detection of key operating variables and assumptions that have a direct effect on the lipid content. The deviation of these variables may lead to an erroneous estimation of the scale-up performance of the technology reviewed in the microalgae-based biodiesel process. The modeling and evaluation of different scenarios of the harvesting, oil extraction and transesterification help to identify greener and cheaper alternatives. (C) 2013 Elsevier Ltd. All rights reserved.
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  350. Microalgal Biodiesel
    Abstract

    Pereira, H.; Amaro, H. M.; Katkam, N. G.; Barreira, L.; Guedes, A. C.; Varela, J.; Malcata, F. X. 2013. Microalgal Biodiesel. Air Pollution Prevention and Control: Bioreactors and Bioenergy. 399-430

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  351. Microalgal biodiesel production via a two-step process with biochar-based acidic catalyst
    Abstract

    Dong, T.; Gao, D. F.; Miao, C.; Chen, S. L. 2013. Microalgal biodiesel production via a two-step process with biochar-based acidic catalyst. Abstracts of Papers of the American Chemical Society. 246

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  352. Microalgal cultivation in wastewater from the fermentation effluent in Riboflavin (B2) manufacturing for biodiesel production
    Abstract

    Sun, X. F.; Wang, C. W.; Li, Z. H.; Wang, W. G.; Tong, Y. J.; Wei, J. 2013. Microalgal cultivation in wastewater from the fermentation effluent in Riboflavin (B2) manufacturing for biodiesel production. Bioresource Technology. 143499-504

    In this work, the acclimation of Chlorella pyrenoidosa in diluted wastewater was studied to produce biomass and remove chemical oxygen demand (COD), ammonia-N and phosphorous. The results indicated that the optimal conditions (the volume ratio of wastewater, light intensity, culture temperature, CO2 concentration in feeding gas) which could influence the wastewater treatment efficiency were 0.05, 250 photons m(-2) s(-1), 28 degrees C and 5%, respectively. Under these conditions, the removal efficiency of COD reached up to 89.2%, while the total nitrogen and total phosphorous decreased by 64.52% and 82.20%, respectively. With the second treatment, COD in the wastewater was further reduced to less than 100 mg/L while it was only reduced to 542.9 mg/L after the first treatment. The treated wastewater could be discharged directly or subjected to for further treatment for recycling. In addition, 1.25 g/L of the biomass and 38.27% (dry basis, w%) of lipid content were reached after microalgal cultivation. (C) 2013 Elsevier Ltd. All rights reserved.
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  353. Microalgal species growing on piggery wastewater as a valuable candidate for nutrient removal and biodiesel production
    Abstract

    Abou-Shanab, R. A.; Ji, M. K.; Kim, H. C.; Paeng, K. J.; Jeon, B. H. 2013. Microalgal species growing on piggery wastewater as a valuable candidate for nutrient removal and biodiesel production. J Environ Manage. 115257-64

    Six microalgal species were examined in this study to determine their effectiveness in the coupling of piggery wastewater treatment and biodiesel production. The dry biomasses of Ourococcus multisporus, Nitzschia cf. pusilla, Chlamydomonas mexicana, Scenedesmus obliquus, Chlorella vulgaris, and Micractinium reisseri were 0.34 +/- 0.08, 0.37 +/- 0.13, 0.56 +/- 0.35, 0.53 +/- 0.30, 0.49 +/- 0.26, and 0.35 +/- 0.08 g dwt/L, respectively. The highest removal of nitrogen (62%), phosphorus (28%), and inorganic carbon (29%) were achieved by C. mexicana. In the absence of microalgae, the spontaneous precipitation of phosphorus, calcium, and inorganic carbon occurred at slightly alkaline pH. The highest lipid productivity and lipid content (0.31 +/- 0.03 g/L and 33 +/- 3%, respectively) were found in C. mexicana. The fatty acid compositions of the studied species were mainly palmitic, linoleic, alpha-linolenic, and oleic. The results of our study suggest that C. mexicana is one of the most promising candidates for simultaneous nutrient removal and high-efficient biodiesel production.
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  354. Microalgal species growing on piggery wastewater as a valuable candidate for nutrient removal and biodiesel production
    Abstract

    Abou-Shanab, R. A. I.; Ji, M. K.; Kim, H. C.; Paeng, K. J.; Jeon, B. H. 2013. Microalgal species growing on piggery wastewater as a valuable candidate for nutrient removal and biodiesel production. Journal of Environmental Management. 115257-264

    Six microalgal species were examined in this study to determine their effectiveness in the coupling of piggery wastewater treatment and biodiesel production. The dry biomasses of Ourococcus multisporus, Nitzschia cf. pusilla, Chlamydomonas mexicana, Scenedesmus obliquus, Chiorella vulgaris, and Micractinium reisseri were 0.34 +/- 0.08, 0.37 +/- 0.13, 0.56 +/- 0.35, 0.53 +/- 0.30, 0.49 +/- 0.26, and 0.35 +/- 0.08 g dwt/L, respectively. The highest removal of nitrogen (62%), phosphorus (28%), and inorganic carbon (29%) were achieved by C mexicana. In the absence of microalgae, the spontaneous precipitation of phosphorus, calcium, and inorganic carbon occurred at slightly alkaline pH. The highest lipid productivity and lipid content (0.31 +/- 0.03 g/L and 33 +/- 3%, respectively) were found in C mexicana. The fatty acid compositions of the studied species were mainly palmitic, linoleic, a-linolenic, and oleic. The results of our study suggest that C mexicana is one of the most promising candidates for simultaneous nutrient removal and high-efficient biodiesel production. (C) 2012 Elsevier Ltd. All rights reserved.
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  355. Microalgal Species Selection for Biodiesel Production Based on Fuel Properties Derived from Fatty Acid Profiles
    Abstract

    Islam, M. A.; Magnusson, M.; Brown, R. J.; Ayoko, G. A.; Nabi, M. N.; Heimann, K. 2013. Microalgal Species Selection for Biodiesel Production Based on Fuel Properties Derived from Fatty Acid Profiles. Energies. 6(11) 5676-5702

    Physical and chemical properties of biodiesel are influenced by structural features of the fatty acids, such as chain length, degree of unsaturation and branching of the carbon chain. This study investigated if microalgal fatty acid profiles are suitable for biodiesel characterization and species selection through Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Graphical Analysis for Interactive Assistance (GAIA) analysis. Fatty acid methyl ester (FAME) profiles were used to calculate the likely key chemical and physical properties of the biodiesel [cetane number (CN), iodine value (IV), cold filter plugging point, density, kinematic viscosity, higher heating value] of nine microalgal species (this study) and twelve species from the literature, selected for their suitability for cultivation in subtropical climates. An equal-parameter weighted (PROMETHEE-GAIA) ranked Nannochloropsis oculata, Extubocellulus sp. and Biddulphia sp. highest; the only species meeting the EN14214 and ASTM D6751-02 biodiesel standards, except for the double bond limit in the EN14214. Chlorella vulgaris outranked N. oculata when the twelve microalgae were included. Culture growth phase (stationary) and, to a lesser extent, nutrient provision affected CN and IV values of N. oculata due to lower eicosapentaenoic acid (EPA) contents. Application of a polyunsaturated fatty acid (PUFA) weighting to saturation led to a lower ranking of species exceeding the double bond EN14214 thresholds. In summary, CN, IV, C18:3 and double bond limits were the strongest drivers in equal biodiesel parameter-weighted PROMETHEE analysis.
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  356. Modeling of biodiesel production in algae cultivation with anaerobic digestion (ACAD)
    Abstract

    Morken, J.; Sapci, Z.; Stromme, J. E. T. 2013. Modeling of biodiesel production in algae cultivation with anaerobic digestion (ACAD). Energy Policy. 6098-105

    This study presents a model of an ecotechnology that combines algae cultivation with anaerobic digestion in order to recycle nutrients and to reduce the need for external energy. The concept is to convert organic waste into several products, such as electricity, biodiesel and organic fertilizer. It is labeled as the ACAD biorefinery. The simulation model of the ACAD biorefinery proved itself to be a powerful tool for understanding the symbioses and dynamics of the system, and therefore also a good tool for reaching political decisions. The model shows that the ACAD biorefinery could be totally independent of external energy supplies. Energy calculations indicate that more energy can be produced by combining the algae cultivation and anaerobic digestion processes. For every unit of energy entering the system in feedstock, 0.6 units of energy are exported as either biodiesel or electricity. The exported electricity accounts for approximately 30% of the total exported energy, while the remaining 70% is exported as biodiesel. By producing its own energy, the biorefinery improves its renewability and level of carbon neutrality. (C) 2013 Elsevier Ltd. All rights reserved.
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  357. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment
    Abstract

    Zhu, L.; Wang, Z.; Shu, Q.; Takala, J.; Hiltunen, E.; Feng, P.; Yuan, Z. 2013. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment. Water Res. 47(13) 4294-302

    An integrated approach, which combined freshwater microalgae Chlorella zofingiensis cultivation with piggery wastewater treatment, was investigated in the present study. The characteristics of algal growth, lipid and biodiesel production, and nutrient removal were examined by using tubular bubble column photobioreactors to cultivate C. zofingiensis in piggery wastewater with six different concentrations. Pollutants in piggery wastewater were efficiently removed among all the treatments. The specific growth rate and biomass productivity were different among all the cultures. As the initial nutrient concentration increased, the lipid content of C. zofingiensis decreased. The differences in lipid and biodiesel productivity of C. zofingiensis among all the treatments mainly resulted from the differences in biomass productivity. It is worthy of note that the diluted piggery wastewater with 1900 mg L(-1) COD provided an optimal nutrient concentration for C. zofingiensis cultivation, where the advantageous nutrient removal and the highest productivities of biomass, lipid and biodiesel were presented.
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  358. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment
    Abstract

    Zhu, L. D.; Wang, Z. M.; Shu, Q.; Takala, J.; Hiltunen, E.; Feng, P. Z.; Yuan, Z. H. 2013. Nutrient removal and biodiesel production by integration of freshwater algae cultivation with piggery wastewater treatment. Water Research. 47(13) 4294-4302

    An integrated approach, which combined freshwater microalgae Chlorella zofingiensis cultivation with piggery wastewater treatment, was investigated in the present study. The characteristics of algal growth, lipid and biodiesel production, and nutrient removal were examined by using tubular bubble column photobioreactors to cultivate C. zofingiensis in piggery wastewater with six different concentrations. Pollutants in piggery wastewater were efficiently removed among all the treatments. The specific growth rate and biomass productivity were different among all the cultures. As the initial nutrient concentration increased, the lipid content of C. zofingiensis decreased. The differences in lipid and biodiesel productivity of C. zofingiensis among all the treatments mainly resulted from the differences in biomass productivity. It is worthy of note that the diluted piggery wastewater with 1900 mg L (1) COD provided an optimal nutrient concentration for C. zofingiensis cultivation, where the advantageous nutrient removal and the highest productivities of biomass, lipid and biodiesel were presented. (C) 2013 Elsevier Ltd. All rights reserved.
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  359. Optimal engineered algae composition for the integrated simultaneous production of bioethanol and biodiesel
    Abstract

    Martin, M.; Grossmann, I. E. 2013. Optimal engineered algae composition for the integrated simultaneous production of bioethanol and biodiesel. Aiche Journal. 59(8) 2872-2883

    The optimization of the composition of the algae for the simultaneous production of bioethanol and biodiesel is presented. We consider two alternative technologies for the biodiesel synthesis from algae oil, enzymatic or homogeneous alkali catalyzed that are coupled with bioethanol production from algae starch. In order to determine the optimal operating conditions, we not only couple the technologies, but simultaneously optimize the production of both biofuels and heat integrate them while optimizing the water consumption. Multi-effect distillation is included to reduce the energy and cooling water consumption for ethanol dehydration. In both cases, the optimal algae composition results in 60% oil, 30% starch, and 10% protein. The best alternative for the production of biofuels corresponds to a production price of 0.35 $/gal, using enzymes, with energy and water consumption values (4.00 MJ/gal and 0.59 gal/gal). (c) 2013 American Institute of Chemical Engineers AIChE J, 59: 2872-2883, 2013
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  360. Optimal processing pathway for the production of biodiesel from microalgal biomass: A superstructure based approach
    Abstract

    Rizwan, M.; Lee, J. H.; Gani, R. 2013. Optimal processing pathway for the production of biodiesel from microalgal biomass: A superstructure based approach. Computers & Chemical Engineering. 58305-314

    In this study, we propose a mixed integer nonlinear programming (MINLP) model for superstructure based optimization of biodiesel production from microalgal biomass. The proposed superstructure includes a number of major processing steps for the production of biodiesel from microalgal biomass, such as the harvesting of microalgal biomass, pretreatments including drying and cell disruption of harvested biomass, lipid extraction, transesterification, and post-transesterfication purification. The proposed model is used to find the optimal processing pathway among the large number of potential pathways that exist for the production of biodiesel from microalgae. The proposed methodology is tested by implementing on a specific case with different choices of objective functions. The MINLP model is implemented and solved in GAMS using a database built in Excel. The results from the optimization are analyzed and their significances are discussed. (C) 2013 Elsevier Ltd. All rights reserved.
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  361. Optimization of lipid production for algal biodiesel in nitrogen stressed cells of Dunaliella salina using FTIR analysis
    Abstract

    Liu, J. Y.; Mukherjee, J.; Hawkes, J. J.; Wilkinson, S. J. 2013. Optimization of lipid production for algal biodiesel in nitrogen stressed cells of Dunaliella salina using FTIR analysis. Journal of Chemical Technology and Biotechnology. 88(10) 1807-1814

    BackgroundLarge improvements in productivity are required to make massive scale biodiesel production from microalgae an economic reality. Although the maximum neutral lipid content of microalgae has received much attention as a target for optimization, there are other factors that are equally important. These are (1) the rates of accumulation of both biomass and lipids and (2) the maximum densities of algal cells that can be sustained in continuous cultivation. The combined effect of these factors for lipid production has not been thoroughly examined in Dunaliella species. Hence this study examines the rates of growth and lipid accumulation in Dunaliella salina using Fourier transform infrared spectroscopy (FTIR) under several combinations of temperatures and cell densities.
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  362. Optimization of microwave-enhanced methanolysis of algal biomass to biodiesel under temperature controlled conditions
    Abstract

    Patil, P.; Reddy, H.; Muppaneni, T.; Ponnusamy, S.; Sun, Y. Q.; Dailey, P.; Cooke, P.; Patil, U.; Deng, S. G. 2013. Optimization of microwave-enhanced methanolysis of algal biomass to biodiesel under temperature controlled conditions. Bioresource Technology. 137278-285

    The effect of a "controlled temperature" approach was investigated in the microwave-enhanced simultaneous extraction and transesterification of dry algae. Experimental runs were designed using a response surface methodology (RSM). The process parameters such as dry algae to methanol ratio, reaction time, and catalyst concentrations were optimized to evaluate their effects on the fatty acid methyl ester (FAME) yield under the "controlled temperature" conditions. Thermal energy associated with the microwave transesterification process was calculated at various temperature levels using the optimized process parameters. Algal biomass characterization and algal biodiesel analysis were carried out using various analytical instruments such as FTIR, TEM, GC-MS and confocal laser scanning microscopy. Thermogravimetric analysis under both nitrogen and oxygen environments was performed to examine the thermal and oxidative stability of the algal fatty acid methyl esters. (C) 2013 Elsevier Ltd. All rights reserved.
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  363. Potential of Microalgae Scenedesmus obliquus Grown in Brewery Wastewater for Biodiesel Production
    Abstract

    Mata, T. M.; Melo, A. C.; Meireles, S.; Mendes, A. M.; Martins, A. A.; Caetano, N. S. 2013. Potential of Microalgae Scenedesmus obliquus Grown in Brewery Wastewater for Biodiesel Production. Icheap-11: 11th International Conference on Chemical and Process Engineering, Pts 1-4. 32901-906

    This work aims to analyze the possibility of growing microalgae Scenedesmus obliquus (S. obliquus) in a brewery wastewater as a potential candidate for biodiesel production. For this purpose S. obliquus was cultivated in a synthetic brewery wastewater at 12,000 Lux of light intensity, with a 12 h period of daily light and aeration. Under these conditions, results revealed an average lipid content of 27 % of dry-weight (dwt) biomass and average biomass and lipid concentrations of respectively, 0.90 and 0.24 g/L (of dwt biomass). The fatty acid methyl esters (FAME) transesterified from the lipids are mainly composed of saturated esters (56.4 %) among which, palmitate (C16:0) is the most significant with a relative percentage of 47.8 % (wt). With regard to the unsaturated esters, the percentage of 10.6 % (wt) obtained for linolenate (C18:3) is below the maximum limit imposed by the EN 14214: 2003 standard for this ester in biodiesel. The average molecular mass of these lipids and FAME are respectively 845.2 and 283.1 g/mol.
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  364. Production of algal biodiesel from marine macroalgae Enteromorpha compressa by two step process: Optimization and kinetic study
    Abstract

    Suganya, T.; Gandhi, N. N.; Renganathan, S. 2013. Production of algal biodiesel from marine macroalgae Enteromorpha compressa by two step process: Optimization and kinetic study. Bioresource Technology. 128392-400

    In this investigation, Enteromorpha compressa algal oil with high free fatty acids (FFA) used as a feedstock for biodiesel production. Two step process was developed and kinetic study executed to obtain reaction rate constant for the transesterification reaction. The acid esterification was carried out to reduce FFA from 6.3% to 0.34% with optimized parameters of 1.5% H2SO4, 12:1 methanol-oil ratio, 400 rpm at 60 degrees C and 90 min of reaction time. The maximum biodiesel yield 90.6% was achieved from base transesterification through optimum conditions of 1% NaOH, 9:1 methanol-oil ratio, 600 rpm and 60 degrees C temperature for 70 min. The algal biodiesel was characterized by GC-MS, HPLC and NIR. This transesterification follows first order reaction kinetics and the activation energy was determined as 73,154.89 J/mol. The biodiesel properties were analyzed and found to be within the limits of American standards. Hence, E. compressa serves as a valuable renewable raw-material for biodiesel production. (C) 2012 Elsevier Ltd. All rights reserved.
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  365. Production of biodiesel from microalgae Chlamydomonas polypyrenoideum grown on dairy industry wastewater
    Abstract

    Kothari, R.; Prasad, R.; Kumar, V.; Singh, D. P. 2013. Production of biodiesel from microalgae Chlamydomonas polypyrenoideum grown on dairy industry wastewater. Bioresource Technology. 144499-503

    This study involves a process of phyco-remediation of dairy industry wastewater by algal strain Chlamydomonas polypyrenoideum. The results of selected algal strain indicated that dairy industry wastewater was good nutrient supplement for algal growth in comparable with BG-11 growth medium. Alga grown on dairy industry wastewater reduced the pollution load of nitrate (90%), nitrite (74%), phosphate (70%), chloride (61%), fluoride (58%), and ammonia (90%) on 10th day of its growth as compared to that of uninoculated wastewater. The lipid content of algal biomass grown on dairy wastewater on 10th day (1.6 g) and 15th day (1.2 g) of batch experiment was found to be higher than the lipid content of algal biomass grown in BG-11 growth medium on 10th day (1.27 g) and 15th day (1.0 g) of batch experiment. The results on FTIR analysis of the extracted bio-oil through transesterification reaction was comparable with bio-oil obtained from other sources. (c) 2013 Elsevier Ltd. All rights reserved.
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  366. Purification of triacylglycerols for biodiesel production from Nannochloropsis microalgae by membrane technology
    Abstract

    Giorno, F.; Mazzei, R.; Giorno, L. 2013. Purification of triacylglycerols for biodiesel production from Nannochloropsis microalgae by membrane technology. Bioresource Technology. 140172-178

    Triacylglycerols recovery from wet microalgae is a key aspect of biodiesel production, because of the energetic balance gained from avoiding biomass drying. In order to isolate TAG from Nannochloropsis cells, the possibility to concentrate biomass and to recover TAG in a single step by membrane process was studied. Different polymeric membranes were selected and screened on the basis of adsorption test and permeation flux. Results showed that membrane of regenerated cellulose (RC) with nominal molecular weight cutoff of 100 kDa and 30 kDa gave the best performance. Indeed, permeate flux was stable during ultrafiltration experiment in concentration mode and no severe fouling/cake deposition was observed. Both membranes allowed to recover permeates with high content of triacylglicerols. However, a more purity of the triacylglicerols from the other co-products was only obtained with the 30 kDa RC membrane because the retention of the unwanted proteins was in the range of 89%. (C) 2013 Published by Elsevier Ltd.
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  367. Screening Microalgae Strains for Biodiesel Production: Lipid Productivity and Estimation of Fuel Quality Based on Fatty Acids Profiles as Selective Criteria
    Abstract

    Nascimento, I. A.; Marques, S. S. I.; Cabanelas, I. T. D.; Pereira, S. A.; Druzian, J. I.; de Souza, C. O.; Vich, D. V.; de Carvalho, G. C.; Nascimento, M. A. 2013. Screening Microalgae Strains for Biodiesel Production: Lipid Productivity and Estimation of Fuel Quality Based on Fatty Acids Profiles as Selective Criteria. Bioenergy Research. 6(1) 1-13

    The viability of algae-based biodiesel industry depends on the selection of adequate strains in regard to profitable yields and oil quality. This work aimed to bioprospecting and screening 12 microalgae strains by applying, as selective criteria, the volumetric lipid productivity and the fatty acid profiles, used for estimating the biodiesel fuel properties. Volumetric lipid productivity varied among strains from 22.61 to 204.91 mg l(-1) day(-1). The highest lipid yields were observed for Chlorella (204.91 mg l(-1) day(1)) and Botryococcus strains (112.43 and 98.00 mg l(-1) day(-1) for Botryococcus braunii and Botryococcus terribilis, respectively). Cluster and principal components analysis analysis applied to fatty acid methyl esters (FAME) profiles discriminated three different microalgae groups according to their potential for biodiesel production. Kirchneriella lunaris, Ankistrodesmus fusiformis, Chlamydocapsa bacillus, and Ankistrodesmus falcatus showed the highest levels of polyunsaturated FAME, which incurs in the production of biodiesels with the lowest (42.47-50.52) cetane number (CN), the highest (101.33-136.97) iodine values (IV), and the lowest oxidation stability. The higher levels of saturated FAME in the oils of Chlamydomonas sp. and Scenedesmus obliquus indicated them as source of biodiesel with higher oxidation stability, higher CN (63.63-64.94), and lower IV (27.34-35.28). The third group, except for the Trebouxyophyceae strains that appeared in isolation, are composed by microalgae that generate biodiesel of intermediate values for CN, IV, and oxidation stability, related to their levels of saturated and monosaturated lipids. Thus, in this research, FAME profiling suggested that the best approach for generating a microalgae-biodiesel of top quality is by mixing the oils of distinct cell cultures.
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  368. Selection of elite microalgae for biodiesel production in tropical conditions using a standardized platform
    Abstract

    Ho, S. H.; Lai, Y. Y.; Chiang, C. Y.; Chen, C. N. N.; Chang, J. S. 2013. Selection of elite microalgae for biodiesel production in tropical conditions using a standardized platform. Bioresource Technology. 147135-142

    Four thermotolerant microalgae were isolated from tropical Taiwan and classified as members of Desmodesmus based on morphological and molecular studies. A platform was established to evaluate their biodiesel production-related traits, including thermotolerance, lipid productivity, lipid oxidative stability and auto-sedimentation. The findings demonstrated thermotolerance of all four species was at the same level, as all could live at 45 degrees C for 24 h and 50 degrees C for 8 h with mortality rates below 5% of cells. The lipid productivity of Desmodesmus sp. F2 reached 113 mg/L/d. Its saturated and monounsaturated fatty acids accounted for 75% of the FAMEs, and it required only 3.1 h to achieve 85% sedimentation. Comparing these traits to those of the other three Desmodesmus and microalgae in the literature, Desmodesmus sp. F2 is one of the best candidates for biodiesel production in tropical and subtropical areas. This platform effectively assessed traits of microalgae related to biodiesel production. (C) 2013 Elsevier Ltd. All rights reserved.
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  369. Techno-economic assessment of carbon-negative algal biodiesel for transport solutions
    Abstract

    Taylor, B.; Xiao, N.; Sikorski, J.; Yong, M.; Harris, T.; Helme, T.; Smallbone, A.; Bhave, A.; Kraft, M. 2013. Techno-economic assessment of carbon-negative algal biodiesel for transport solutions. Applied Energy. 106262-274

    This paper presents a techno-economic analysis of carbon-negative algal biodiesel production routes that use currently available technologies. The production process includes the following stages: carbon-neutral renewable electricity generation for powering the plant, algal growth in photobioreactors, algae dewatering and lipid extraction, and biofuel conversion and refining. As carbon dioxide is consumed in the algal growth process, side products are not burned (with CO2 release), and the energy supplied to the entire production process is obtained from concentrated solar power, the whole system is assumed carbon footprint negative. Under assumptions related to economics of scale, the techno-economic model is extended to account for varying industrial scales of production. Verified data from a selection of commercially available technologies are used as inputs for the model, and the economic viability of the various production routes is assessed. From the various routes investigated, one scheme involving combined gasification and Fischer-Tropsch of algal solids to produce biodiesel along with conversion of algal lipids into biodiesel through transesterification was found to be promising. Assuming a typical economic scaling factor of 0.8, an algal biodiesel process with an annual production rate of 100 Mt/year is identified to achieve a biodiesel price comparable to the current conventional diesel price (approximately 1.39 pound/litre at the pump, or $114/barrel of crude) with a discounted break-even time of 6 years. (C) 2013 Elsevier Ltd. All rights reserved.
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  370. Two-step in situ biodiesel production from microalgae with high free fatty acid content
    Abstract

    Dong, T.; Wang, J.; Miao, C.; Zheng, Y. B.; Chen, S. L. 2013. Two-step in situ biodiesel production from microalgae with high free fatty acid content. Bioresource Technology. 1368-15

    The yield of fatty acid methyl ester (FAME) from microalgae biomass is generally low via traditional extraction-conversion route due to the deficient solvent extraction. In this study a two-step in situ process was investigated to obtain a high FAME yield from microalgae biomass that had high free fatty acids (FFA) content. This was accomplished with a pre-esterification process using heterogeneous catalyst to reduce FFA content prior to the base-catalyzed transesterification. The two-step in situ process resulted in a total FAME recovery up to 94.87 +/- 0.86%, which was much higher than that obtained by a one-step acid or base catalytic in situ process. The heterogeneous catalyst, Amberlyst-15, could be used for 8 cycles without significant loss in activity. This process have the potential to reduce the production cost of microalgae-derived FAME and be more environmental compatible due to the higher FAME yield with reduced catalyst consumption. (C) 2013 Published by Elsevier Ltd.
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  371. Using wet microalgae for direct biodiesel production via microwave irradiation
    Abstract

    Cheng, J.; Yu, T.; Li, T.; Zhou, J. H.; Cen, K. F. 2013. Using wet microalgae for direct biodiesel production via microwave irradiation. Bioresource Technology. 131531-535

    To address the large energy consumption of microalgae dewatering and to simplify the conventional two-step method (cellular lipid extraction and lipid transesterification) for biodiesel production, a novel process for the direct conversion of wet microalgae biomass into biodiesel by microwave irradiation is proposed. The influences of conventional thermal heating and microwave irradiation on biodiesel production from wet microalgae biomass were investigated. The effects of using the one-step (simultaneous lipid extraction and transesterification) and two-step methods were also studied. Approximately 77.5% of the wet microalgal cell walls were disrupted under microwave irradiation. The biodiesel production rate and yield from wet microalgae biomass obtained through the one-step process using microwave irradiation were 6-fold and 1.3-fold higher than those from wet microalgae obtained through the two-step process using conventional heating. (C) 2013 Elsevier Ltd. All rights reserved.
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  372. An economic, sustainability, and energetic model of biodiesel production from microalgae
    Abstract

    Delrue, F.; Seiter, P. A.; Sahut, C.; Cournac, L.; Roubaud, A.; Peltier, G.; Froment, A. K. 2012. An economic, sustainability, and energetic model of biodiesel production from microalgae. Bioresource Technology. 111191-200

    A new process evaluation methodology of microalgae biodiesel has been developed. Based on four evaluation criteria, i.e. the net energy ratio (NER), biodiesel production costs, greenhouse gases (GHG) emission rate and water footprint, the model compares various technologies for each step of the process, from cultivation to oil upgrading. An innovative pathway (hybrid raceway/PBR cultivation system, belt filter press for dewatering. wet lipid extraction, oil hydrotreating and anaerobic digestion of residues) shows good results in comparison to a reference pathway (doubled NER, lower GHG emission rate and water footprint). The production costs are still unfavourable (between 1.99 and 3.35 (sic)/L of biodiesel). The most influential parameters have been targeted through a global sensitivity analysis and classified: (i) lipid productivity, (ii) the cultivation step, and (iii) the downstream processes. The use of low-carbon energy sources is required to achieve significant reductions of the biodiesel GHG emission rate compared to petroleum diesel. (C) 2012 Elsevier Ltd. All rights reserved.
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  373. Analysis of Macroalgae Oil Transesterification for Biodiesel Production
    Abstract

    Urrejola, S.; Maceiras, R.; Perez, L.; Cancela, A.; Sanchez, A. 2012. Analysis of Macroalgae Oil Transesterification for Biodiesel Production. Pres 2012: 15th International Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction. 291153-1158

    In this research, the kinetic of the transesterification of algae oil with methanol in presence of sodium hydroxide was studied. The final conversion was determined using the acid value and it was obtained a conversion of 70 % at 8 h. The experimental results were found to fit a first-order kinetics. Finally, the kinetic constant was determined for the algae oil transesterification.
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  374. Biodiesel Production and Biotechnological Applications from Microalgae Isolated from Water System of Riyadh, Saudi Arabia
    Abstract

    Sholkamy, E. N.; Abdel-Megeed, A.; Elnakieb; Fatma, A. A.; Al-Arfaj, A. 2012. Biodiesel Production and Biotechnological Applications from Microalgae Isolated from Water System of Riyadh, Saudi Arabia. Journal of Pure and Applied Microbiology. 6(4) 1653-1662

    Microalgae are a potential source of biodiesel. Isolates of the present study were isolated from Wadi-henifa, Rhiyad, Saudi Arabia. The urgent need for an alternative and sustainable energy has created renewed interest to analyse the microalgae for biodiesel production. The greatest lipid content reached 20.2, 16.4, 9.7 and 12.3 To under the optimal conditions of nitrate concentration (0.75 g/l), temperature (24 and 30 degrees C), salinity (0.05 and 0.001 mole/l) and pH (8 with Chlorellavulgarus and 9 with other strains), Chlorella vulgarusArthrospiraplatensisGomont and Spirulina major, respectively. It was demonstrated that the obtained model was effective for predicting lipid productivity of the isolated microalgae. The maximum protein content was at 24 degrees C for Chlorella vulgarus,ArthrospiraplatensisGomont and Spirulinamajorkutz, (53, 56.8 and 54 % respectively), while the maximum protein content of Arthrospira maxima was at 30 degrees C (56.2 %).The optimum protein content was found at pH9 for Arthrospiraplatensis Gomont, Spirulina major kutzand Arthrospira maxima(48.47, 55.47 and 63.25 % respectively) while in case of Chlorella vulgarus was at pH 8 (51 %).The maximum protein content was 76.96 To at 0.001 mole Nacl/L, 54, 75.38 and 75.09 % at 0.05 mole/L for Chlorella vulgarus,Spirulina major kutz, Arthrospira maxima and Arthrospiraplatensis Gomont respectively. Results of this study revealed thatthe mention optimization conditions enhanced protein content of the tested isolates. ArthrospiraplatensisGomont, Spirulinamajor kutzand Arthrospira maxima are promising organisms with high nutritional value for animal and human beings.
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  375. Biodiesel Production from Algae
    Abstract

    Khola, G.; Ghazala, B. 2012. Biodiesel Production from Algae. Pakistan Journal of Botany. 44(1) 379-381

    Algae appear to be an emerging source of biomass for biodiesel that has the potential to completely displace fossil fuel. Two thirds of earth's surface is covered with water, thus algae would truly be renewable option of great potential for global energy needs. This study discusses specific and comparative biodiesel quantitative potential of Cladophora sp., also highlighting its biomass (after oil extraction), pH and sediments (glycerine, water and pigments) quantitative properties. Comparison of Cladophora sp., with Oedogonium sp., and Spirogyra sp., (Hossain et al., 2008) shows that Cladophora sp., produce higher quantity of biodiesel than Spirogyra sp., whereas biomass and sediments were higher than the both algal specimens in comparison to the results obtained by earlier workers. No prominent difference in pH of biodiesel was found. In Pakistan this is a first step towards biodiesel production from algae. Results indicate that Cladophora sp., provide a reasonable quantity of biodiesel, its greater biomass after oil extraction and sediments make it a better option for biodiesel production than the comparing species.
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  376. Biodiesel production from algae oil high in free fatty acids by two-step catalytic conversion
    Abstract

    Chen, L.; Liu, T. Z.; Zhang, W.; Chen, X. L.; Wang, J. F. 2012. Biodiesel production from algae oil high in free fatty acids by two-step catalytic conversion. Bioresource Technology. 111208-214

    The effect of storage temperature and time on lipid composition of Scenedesmus sp. was studied. When stored at 4 degrees C or higher, the free fatty acid content in the wet biomass increased from a trace to 62.0% by day 4. Using two-step catalytic conversion, algae oil with a high free fatty acid content was converted to biodiesel by pre-esterification and transesterification. The conversion rate of triacylglycerols reached 100% under the methanol to oil molar ratio of 12:1 during catalysis with 2% potassium hydroxide at 65 degrees C for 30 min. This process was scaled up to produce biodiesel from Scenedesmus sp. and Nannochloropsis sp. oil. The crude biodiesel was purified using bleaching earth. Except for moisture content, the biodiesel conformed to Chinese National Standards. (C) 2012 Elsevier Ltd. All rights reserved.
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  377. Biodiesel production from microalgae
    Abstract

    Esen, M.; Urek, R. O. 2012. Biodiesel production from microalgae. New Biotechnology. 29S43-S43

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  378. Biodiesel production from microalgae
    Abstract

    Veillette, M.; Giroir-Fendler, A.; Faucheux, N.; Heitz, M. 2012. Biodiesel production from microalgae. Management of Natural Resources, Sustainable Development and Ecological Hazards Iii. 148465-473

    By 2020, according to several government policies like the European Union countries, road transportation fuels must contain at least 10% (v/v) biofuel like biodiesel. Consequently, the world biodiesel production is expected to rise in the next years. However, most biodiesel is produced from vegetable oils, which compete with human food production. Biodiesel from microalgae could help to reach the requested level of biofuel (biodiesel) without endangering the world food supply because microalgae cultivation does not compete with arable land. Nevertheless, the cost of biodiesel production from microalgae must be lowered. One of the main challenges is to extract the lipids from the microalgae and to transform them into biodiesel.
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  379. Biodiesel production from microalgae: Co-location with sugar mills
    Abstract

    Lohrey, C.; Kochergin, V. 2012. Biodiesel production from microalgae: Co-location with sugar mills. Bioresource Technology. 10876-82

    Co-location of algae production facilities with cane sugar mills can be a technically advantageous path towards production of biodiesel. Algal biodiesel production was integrated with cane sugar production in the material and energy balance simulation program Sugars (TM). A model was developed that allowed comparison of production scenarios involving dewatering the algae to 20% ds (dry solids) or 30% ds prior to thermal drying. The net energy ratio, E-R (energy produced/energy consumed) of the proposed process was found to be 1.5. A sensitivity analysis showed that this number ranged from 0.9 to 1.7 when the range of values for oil content, CO2 utilization, oil conversion, and harvest density reported in the literature were evaluated. By utilizing available waste-resources from a 10,000 ton/d cane sugar mill, a 530 ha algae farm can produce 5.8 million L of biodiesel/yr and reduce CO2 emissions of the mill by 15% without the need for fossil fuels. Published by Elsevier Ltd.
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  380. Biodiesel production from microalgal isolates of southern Pakistan and quantification of FAMEs by GC-MS/MS analysis
    Abstract

    Musharraf, S. G.; Ahmed, M. A.; Zehra, N.; Kabir, N.; Choudhary, M. I.; Rahman, A. U. 2012. Biodiesel production from microalgal isolates of southern Pakistan and quantification of FAMEs by GC-MS/MS analysis. Chemistry Central Journal. 6

    Background: Microalgae have attracted major interest as a sustainable source for biodiesel production on commercial scale. This paper describes the screening of six microalgal species, Scenedesmus quadricauda, Scenedesmus acuminatus, Nannochloropsis sp., Anabaena sp., Chlorella sp. and Oscillatoria sp., isolated from fresh and marine water resources of southern Pakistan for biodiesel production and the GC-MS/MS analysis of their fatty acid methyl esters (FAMEs).
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  381. Biomass productivity and productivity of fatty acids and amino acids of microalgae strains as key characteristics of suitability for biodiesel production
    Abstract

    Hempel, N.; Petrick, I.; Behrendt, F. 2012. Biomass productivity and productivity of fatty acids and amino acids of microalgae strains as key characteristics of suitability for biodiesel production. Journal of Applied Phycology. 24(6) 1407-1418

    Microalgae are discussed as an alternative source for the production of biofuels. The lipid content compared to cultivation time of used species is the main reason for any choice of a special strain. This paper reviews more analytical data of 38 screened microalgae strains. After the cultivation period, total content of lipids was analysed. The extracted fatty acids were quantified as fatty acid methyl esters by GC analysis. The amino acids were analysed by HPLC. Chlorella sp., Chlorella saccharophila, Chlorella minutissima and Chlorella vulgaris were identified as species with the highest productivity of fatty acids relevant to transesterification reactions. The components were mainly linoleic acid, palmitic acid and oleic acid. To increase productivity of highly saturated fatty acids, cultivation parameters light intensity and temperature were varied. In this manner, the ideal conditions for biodiesel production were defined in this publication.
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  382. Chemical and physical properties of algal methyl ester biodiesel containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate
    Abstract

    Bucy, H. B.; Baumgardner, M. E.; Marchese, A. J. 2012. Chemical and physical properties of algal methyl ester biodiesel containing varying levels of methyl eicosapentaenoate and methyl docosahexaenoate. Algal Research-Biomass Biofuels and Bioproducts. 1(1) 57-69

    Microalgae are currently receiving strong consideration as an advanced biofuel feedstock because of their theoretically high yield (gal/acre/year) in comparison to terrestrial vegetable oil feedstocks. Microalgal lipids can be readily converted into a variety of biofuels including fatty acid methyl esters (i.e. biodiesel) via transesterification or alkanes via hydroprocessing. In contrast to paraffinic fuels whose properties can be tailored for a specific application, the properties of algal methyl ester biodiesel are directly related to the fatty acid composition of the algal lipids. Several microalgae species that are suitable for large scale cultivation such as those in the genus Nannochloropsis produce lipids that contain long chain-polyunsaturated fatty acids (LC-PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These constituents have high value as co-products but are problematic in terms of biodiesel properties such as ignition quality and oxidative stability. The objective of this study was to examine the effect of varying levels of EPA and DHA on algal methyl ester fuel properties. Oxidative stability, Cetane Number, density, viscosity, bulk modulus, cloud point and cold filter plugging point were measured for algal methyl esters produced from various microalgae feedstocks as well as model algal methyl ester compounds formulated to match the fatty acid composition of Nannochloropsis sp., Nannochloropsis oculata and Isochlysis galbana subjected to varying levels of removal of EPA and DHA. The results suggest that removal of 50 to 80% of the LC-PUFA from Nannochloropsis-based methyl esters would be sufficient for meeting existing specifications for oxidative stability. However, higher levels of LC-PUFA removal from Nannochloropsis-based methyl esters would be required to produce fuels with acceptable Cetane Number. The removal of EPA and DHA was shown to have a detrimental effect on cold flow properties since the algal methyl esters are also high in fully saturated fatty acid content. (C) 2012 Elsevier B.V. All rights reserved.
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  383. Comparative Techno-economic Analysis of Biodiesel Production from Microalgae via Transesterification Methods
    Abstract

    Bello, B. Z.; Nwokoagbara, E.; Wang, M. H. 2012. Comparative Techno-economic Analysis of Biodiesel Production from Microalgae via Transesterification Methods. 22 European Symposium on Computer Aided Process Engineering. 30132-136

    Microalgae, which hold great potential for carbon neutral biofuels production, is regarded as one of the most viable options to serve as sustainable feedstock for biodiesel production. This paper analyses two processes for biodiesel production from microalgae (Chlorella Protothecoides). The analysis showed that the energy efficiency of the supercritical transesterification process is 52.85% with the most energy (75.55%) used in the separation step of the process. The alkali-catalysed process has 49.67% energy efficiency with 35.25% used in the biodiesel purification step. The supercritical process requires higher capital cost, the alkali-catalysed process requires slightly higher production cost due to higher number of unit operations and processing steps. It was found that technically, the non-catalytic supercritical transesterification method has higher energy efficiency, but the unit price of the biodiesel is slightly lower via the alkali-catalysed transesterification method.
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  384. Computer aided evaluation of eco-efficiency of solvent-based algae oil extraction processes for biodiesel production
    Abstract

    Pardo, Y.; Peralta, Y.; Gonzalez, A.; Kafarov, V. 2012. Computer aided evaluation of eco-efficiency of solvent-based algae oil extraction processes for biodiesel production. 22 European Symposium on Computer Aided Process Engineering. 3086-90

    This paper provides an environmental assessment and exergy analysis for the extraction of oil of microalgae. In this work, three solvent extraction methods are simulated with the Aspen Plus (R) 7.1 software, using as feedstock the microalgae genera Chorella sp. The solvent-based methods evaluated were methanol/chloroform, ethanol/hexane, and in situ-hexane extraction; operating conditions for each method were adjusted with experimental work. Mass, energy and exergy balances for each method were performed. The impact categories considered were: Global Warming (GWP100), acidification, eutrophication, photochemical oxidation, ozone layer depletion (ODP) and non-renewable fossil; each one were evaluated with the SIMAPRO 7.1 software. The environmental assessment was applied following the procedures established by the ISO 14040 and 14044 (2006) standards. Finally, exergetic losses, efficiency and environmental profile were calculated for the process. The environmental assessment and exergy analysis confirms the potential of third generation biofuels as an energy source, but is necessary to perform some technical improvements in the oil extraction stage to increase exergetic efficiency and to reduce environmental impacts of the process.
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  385. Current Status and Prospects of Biodiesel Production from Microalgae
    Abstract

    Wu, X. D.; Ruan, R. S.; Du, Z. Y.; Liu, Y. H. 2012. Current Status and Prospects of Biodiesel Production from Microalgae. Energies. 5(8) 2667-2682

    Microalgae represent a sustainable energy source because of their high biomass productivity and ability to remove air and water born pollutants. This paper reviews the current status of production and conversion of microalgae, including the advantages of microalgae biodiesel, high density cultivation of microalgae, high-lipid content microalgae selection and metabolic control, and innovative harvesting and processing technologies. The key barriers to commercial production of microalgae biodiesel and future perspective of the technologies are also discussed.
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  386. Economic and environmental evaluation of microalgae biodiesel production using process simulation tools
    Abstract

    Brunet, R.; Carrasco, D.; Munoz, E.; Guillen-Gosalbez, G.; Katakis, I.; Jimenez, L. 2012. Economic and environmental evaluation of microalgae biodiesel production using process simulation tools. 22 European Symposium on Computer Aided Process Engineering. 30547-551

    This work introduces a systematic method for the economic and environmental analysis and design of new technologies applied to the 3rd generation (from microalgae) biodiesel production process. The evaluation method is based on the integrated use of process simulation techniques with economic and environmental models. The approach is applied to a new technology introduced by some of the authors, where the glycerol produced in the transesterification is used as carbon source for microalgae growth. Firstly, a state of the art biodiesel production plant in the process simulator it is modelled and the economical and environmental performance is computed. Then, the new technology is introduced and its performance are compared. The method presented is very useful for decision-makers in order to evaluate the inclusion of new technologies to improve the chemical process operation and topological designs.
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  387. Effect of light intensity on algal biomass accumulation and biodiesel production for mixotrophic strains Chlorella kessleri and Chlorella protothecoide cultivated in highly concentrated municipal wastewater
    Abstract

    Li, Y.; Zhou, W.; Hu, B.; Min, M.; Chen, P.; Ruan, R. R. 2012. Effect of light intensity on algal biomass accumulation and biodiesel production for mixotrophic strains Chlorella kessleri and Chlorella protothecoide cultivated in highly concentrated municipal wastewater. Biotechnol Bioeng. 109(9) 2222-9

    In this research, the effect of light intensity on biomass accumulation, wastewater nutrient removal through algae cultivation, and biodiesel productivity was investigated with algae species Chlorella kessleri and Chlorella protothecoide. The light intensities studied were 0, 15, 30, 60, 120, and 200 micromol m(-2) s(-1). The results showed that light intensity had profound impact on tested responses for both strains, and the dependence of these responses on light intensity varied with different algae strains. For C. kessleri, the optimum light intensity was 120 micromol m(-2) S(-1) for all responses except for COD removal. For C. protothecoide, the optimum light intensity was 30 micromol m(-2) S(-1). The major components of the biodiesel produced from algae biomass were 16-C and 18-C FAME, and the highest biodiesel contents were 24.19% and 19.48% of dried biomass for C. kessleri and C. protothecoide, respectively. Both species were capable of wastewater nutrients removal under all lighting conditions with high removal efficiencies.
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  388. Effect of light intensity on algal biomass accumulation and biodiesel production for mixotrophic strains Chlorella kessleri and Chlorella protothecoide cultivated in highly concentrated municipal wastewater
    Abstract

    Li, Y. C.; Zhou, W. G.; Hu, B.; Min, M.; Chen, P.; Ruan, R. R. 2012. Effect of light intensity on algal biomass accumulation and biodiesel production for mixotrophic strains Chlorella kessleri and Chlorella protothecoide cultivated in highly concentrated municipal wastewater. Biotechnology and Bioengineering. 109(9) 2222-2229

    In this research, the effect of light intensity on biomass accumulation, wastewater nutrient removal through algae cultivation, and biodiesel productivity was investigated with algae species Chlorella kessleri and Chlorella protothecoide. The light intensities studied were 0, 15, 30, 60, 120, and 200?mu mol?m-2?s-1. The results showed that light intensity had profound impact on tested responses for both strains, and the dependence of these responses on light intensity varied with different algae strains. For C. kessleri, the optimum light intensity was 120?mu mol?m-2?S-1 for all responses except for COD removal. For C. protothecoide, the optimum light intensity was 30?mu mol?m-2?S-1. The major components of the biodiesel produced from algae biomass were 16-C and 18-C FAME, and the highest biodiesel contents were 24.19% and 19.48% of dried biomass for C. kessleri and C. protothecoide, respectively. Both species were capable of wastewater nutrients removal under all lighting conditions with high removal efficiencies. Biotechnol. Bioeng. 2012;109: 22222229. (c) 2012 Wiley Periodicals, Inc.
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  389. Energy analysis and environmental impacts of microalgal biodiesel in China
    Abstract

    Liao, Y. F.; Huang, Z. H.; Ma, X. Q. 2012. Energy analysis and environmental impacts of microalgal biodiesel in China. Energy Policy. 45142-151

    The entire life cycle of biodiesel produced by microalgal biomasses was evaluated using the method of life cycle assessment (LCA) to identify and quantify the fossil energy requirements and environmental impact loading of the system. The life cycle considers microalgae cultivation, harvesting, drying, oil extraction, anaerobic digestion, oil transportation, esterification, biodiesel transportation and biodiesel combustion. The investigation results show that the fossil energy requirement for the biodiesel production is 0.74 MJ/MJ biodiesel, indicating that 1 MJ of biodiesel requires an input of 0.74 MJ of fossil energy. Accordingly, biodiesel production is feasible as an energy producing process. The environmental impact loading of microalgal biodiesel is 3.69 PET2010 (Person Equivalents, Targeted, in 2010) and the GWP is 0.16 kg CO2-eq/MJ biodiesel. The effects of photochemical ozone formation were greatest among all calculated categorization impacts. The fossil energy requirement and GWP in this operation were found to be particularly sensitive to oil content, drying rate and esterification rate. Overall, the results presented herein indicate that the cultivation of microalgae has the potential to produce an environmentally sustainable feedstock for the production of biodiesel. (C) 2012 Elsevier Ltd. All rights reserved.
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  390. Energy balance and environmental impact analysis of marine microalgal biomass production for biodiesel generation in a photobioreactor pilot plant
    Abstract

    Sevigne-Itoiz, E.; Fuentes-Grunewald, C.; Gasol, C. M.; Garces, E.; Alacid, E.; Rossi, S.; Rieradevall, J. 2012. Energy balance and environmental impact analysis of marine microalgal biomass production for biodiesel generation in a photobioreactor pilot plant. Biomass & Bioenergy. 39324-335

    A life cycle assessment (LCA) and an energy balance analysis of marine microalgal biomass production were conducted to determine the environmental impacts and the critical points of production for large scale planning. The artificial lighting and temperature conditions of an indoor bubble column photobioreactor (bcPBR) were compared to the natural conditions of an equivalent outdoor system. Marine microalgae, belonging to the dinoflagellate and raphidophyte groups, were cultured and the results were compared with published LCA data obtained from green microalgae (commonly freshwater algae). Among the species tested, Alexandrium minutum was chosen as the target marine microalgae for biomass production under outdoor conditions, although there were no substantial differences between any of the marine microalgae studied. Under indoor culture conditions, the total energy input for A. minutum was 923 MJ kg (1) vs. 139 MJ kg (1) for outdoor conditions. Therefore, a greater than 85% reduction in energy requirements was achieved using natural environmental conditions, demonstrating the feasibility of outdoor culture as an alternative method of bioenergy production from marine microalgae. The growth stage was identified as the principal source of energy consumption for all microalgae tested, due to the electricity requirements of the equipment, followed by the construction material of the bcPBR. The global warming category (GWP) was 6 times lower in outdoor than in indoor conditions. Although the energy balance was negative under both conditions, this study concludes with suggestions for improvements in the outdoor system that would allow up-scaling of this biomass production technology for outdoor conditions in the Mediterranean. (C) 2012 Elsevier Ltd. All rights reserved.
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  391. Enzymatic production of microalgal biodiesel in ionic liquid [BMIm][PF6]
    Abstract

    Lai, J. Q.; Hu, Z. L.; Wang, P. W.; Yang, Z. 2012. Enzymatic production of microalgal biodiesel in ionic liquid [BMIm][PF6]. Fuel. 95(1) 329-333

    Microalgae have been taken as a sustainable energy source for biodiesel production. In this work, oils were extracted from microalgae Botryococcus braunii (two strains, BB763 and BB764), Chlorella vulgaris (CV), and Chlorella pyrenoidosa (CP). The highest lipid content was produced from CV (40.7%, w/w), whereas the lowest from CP (2.2%, w/w). The major fatty acid components of the microalgal oil from CP include myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3), and their mass proportion is 1:3.9:1.9:4.2:4.3:13.8. Enzymatic production of biodiesel from the microalgal oil was investigated, catalyzed by two immobilized lipases, Penicillium expansum lipase (PEL) and Candida antarctica lipase B (Novozym 435), in two solvent systems: an ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, [BMIm][PF6]) and an organic solvent (tert-butanol). The effect of the following factors on the production yield was studied for all the four reaction systems: methanol/oil molar ratio, reaction temperature, solvent volume, and water content. Under optimal conditions, both enzymes induced significantly higher yields in the IL (90.7% and 86.2%) relative to that obtained in tert-butanol (48.6% and 44.4%), while the PEL-catalyzed conversions were comparable to or slightly higher than those catalyzed by Novozym 435. These results demonstrate that ionic liquids offer a promising new type of solvent for enzymatic production of microalgal biodiesel and that PEL can be employed as an efficient catalyst for such application. (C) 2011 Elsevier Ltd. All rights reserved.
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  392. Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase
    Abstract

    Tran, D. T.; Yeh, K. L.; Chen, C. L.; Chang, J. S. 2012. Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase. Bioresource Technology. 108119-127

    An indigenous microalga Chlorella vulgaris ESP-31 grown in an outdoor tubular photobioreactor with CO2 aeration obtained a high oil content of up to 63.2%. The microalgal oil was then converted to biodiesel by enzymatic transesterification using an immobilized lipase originating from Burkholderia sp. C20. The conversion of the microalgae oil to biodiesel was conducted by transesterification of the extracted microalgal oil (M-I) and by transesterification directly using disrupted microalgal biomass (M-II). The results show that M-II achieved higher biodiesel conversion (97.3 wt% oil) than M-I (72.1 wt% oil). The immobilized lipase worked well when using wet microalgal biomass (up to 71% water content) as the oil substrate. The immobilized lipase also tolerated a high methanol to oil molar ratio (>67.93) when using the M-II approach, and can be repeatedly used for six cycles (or 288 h) without significant loss of its original activity. (c) 2012 Elsevier Ltd. All rights reserved.
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  393. Erratum to: Microalgal fatty acid composition: implications for biodiesel quality (vol 24, pg 791, 2012)
    Abstract

    Stansell, G. R.; Gray, V. M.; Sym, S. D. 2012. Erratum to: Microalgal fatty acid composition: implications for biodiesel quality (vol 24, pg 791, 2012). Journal of Applied Phycology. 24(4) 985-985

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  394. Extraction of oil from microalgae for biodiesel production: A review
    Abstract

    Halim, R.; Danquah, M. K.; Webley, P. A. 2012. Extraction of oil from microalgae for biodiesel production: A review. Biotechnology Advances. 30(3) 709-732

    The rapid increase of CO2 concentration in the atmosphere combined with depleted supplies of fossil fuels has led to an increased commercial interest in renewable fuels. Due to their high biomass productivity, rapid lipid accumulation, and ability to survive in saline water, microalgae have been identified as promising feedstocks for industrial-scale production of carbon-neutral biodiesel. This study examines the principles involved in lipid extraction from microalgal cells, a crucial downstream processing step in the production of microalgal biodiesel. We analyze the different technological options currently available for laboratory-scale microalgal lipid extraction, with a primary focus on the prospect of organic solvent and supercritical fluid extraction. The study also provides an assessment of recent breakthroughs in this rapidly developing field and reports on the suitability of microalgal lipid compositions for biodiesel conversion. (C) 2012 Elsevier Inc. All rights reserved.
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  395. Fatty acid profiling and molecular characterization of some freshwater microalgae from India with potential for biodiesel production
    Abstract

    Kaur, S.; Sarkar, M.; Srivastava, R. B.; Gogoi, H. K.; Kalita, M. C. 2012. Fatty acid profiling and molecular characterization of some freshwater microalgae from India with potential for biodiesel production. New Biotechnology. 29(3) 332-344

    We determined the fatty acid compositions of six species of freshwater microalgae belonging to the Chlorophyta, which were isolated from freshwater bodies in Assam, India. All six microalgae - Desmodesmus sp. DRLMA7, Desmodesmus elegans DRLMA13, Scenedesmus sp. DRLMA5, Scenedesmus sp. DRLMA9 Chlorella sp. DRLMA3 and Chlorococcum macrostigmatum DRLMA12-showed similar fatty acid profiles 16:0, 16:4, 18:1, 18:2, and 18:3 as major components. We also compared fatty acid compositions during the late exponential and stationary growth phases of D. elegans DRLMA13 and Scenedesmus sp. DRLMA9 in BG11 medium. We observed enhanced percentages of total saturated and monounsaturated fatty acids with a concomitant decrease in polyunsaturated fatty acid content upon the prolonged cultivation of both microalgae. Distinct morphological features of microalgal isolates were determined by scanning electron microscopic (SEM) studies. An ornamented cell wall was found in D. elegans DRLMA13, which is characteristic of small spineless species of Desmodesmus. The isolated microalgae were further distinguished through analysis of internal transcribed spacer 2 (ITS2) secondary structures and compensatory base changes (CBCs). Analysis of CBCs showed the relatedness of Chlorella sp. DRLMA3 with other Chlorella-like organisms, but it does not belong to the clade comprising Chlorella sensu stricto, which includes Chlorella vulgaris. The CBC count between Scenedesmus sp. DRLMA9 and other species of Scenedesmus provides evidence that this isolate represents a new species.
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  396. Feasibility study of microalgal and jatropha biodiesel production plants: Exergy analysis approach
    Abstract

    Ofori-Boateng, C.; Keat, T. L.; JitKang, L. 2012. Feasibility study of microalgal and jatropha biodiesel production plants: Exergy analysis approach. Applied Thermal Engineering. 36141-151

    The exergy analyses performed in this study are based on three thermodynamic performance parameters namely exergy destruction, exergy efficiency and thermodynamic improvement potentials. After mathematical analysis with Aspen Plus software, the results showed that 64% and 44% of the total exergy content of the input resources into microalgal methyl ester (MME) and jatropha methyl ester (JME) production plants were destroyed respectively for 1 ton of biodiesel produced. This implies that only 36% and 56% (for MME and JME production plants respectively) useful energy in the products is available to do work. The highest and lowest exergy destructions were recorded in the oil extraction units (38% and 39% of the total exergy destroyed for MME and JME plants respectively) and transesterification units (5% and 2% of total exergy destroyed for MME and JME plants respectively) respectively for 1 ton biodiesel produced. Since sustainable biodiesel production depends on cultivation of feedstock, oil extraction and transesterification processes, exergy analysis which is carried out on only the transesterification unit cannot justify the thermodynamic feasibility of the whole biodiesel production plant unless a complete thermodynamic assessment has been done for the whole plant Thus, according to this study which considers all the biodiesel production processes. MME and JME production plants are not thermodynamically feasible. (C) 2011 Elsevier Ltd. All rights reserved.
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  397. Fuel Properties of Highly Polyunsaturated Fatty Acid Methyl Esters. Prediction of Fuel Properties of Algal Biodiesel
    Abstract

    Knothe, G. 2012. Fuel Properties of Highly Polyunsaturated Fatty Acid Methyl Esters. Prediction of Fuel Properties of Algal Biodiesel. Energy & Fuels. 26(8) 5265-5273

    Biodiesel, defined as the monoalkyl esters of vegetable oils and animal fats, can be derived from other triacylglycerol-containing feedstocks. Algae are being considered for this purpose due to their claimed high production potential. However, there are no comprehensive reports regarding the fuel properties of biodiesel obtained from algal oils. Algal oils, with examples of some exceptions also mentioned here, often contain significant amounts of saturated and highly polyunsaturated (>= 4 double bonds) fatty acid chains which influence fuel properties of the resulting biodiesel. In this connection, the relevant fuel properties of biodiesel from algal oils and the important fuel properties of highly polyunsaturated fatty acid methyl esters as they would occur in many biodiesel fuels obtained from algal oils, have not yet been reported. To fill this gap, in the present work for the first time two neat highly polyunsaturated fatty acid methyl esters with more than three double bonds, methyl 5(Z),8(Z),11(414(Z)-eicosatetraenoate (C20:4) and methyl 4(Z),7(Z),10(Z),13(Z),l 6(Z),19(Z)-docosahexaenoate (C22:6), were investigated. The cetane numbers were determined as 29.6 for C20:4 and 24.4 for C22:6. Kinematic viscosity values were observed as 3.11 mm(2)/s for C20:4 and 2.97 mm(2)/s for C22:6, while oxidative stability values were below 0.1 h for both by the Rancimat test while densities were above 0.9 g/cm(3). Two polyunsaturated C20 methyl esters, methyl 11(Z),14(Z)-eicosadienoate and 11(Z),14(Z),17(Z)-eicosatrienoate, were also studied for kinematic viscosity, density, and oxidative stability to expand the database on these properties of C20 compounds and provide additional data to predict the properties of other highly polyunsaturated fatty acid methyl esters. Properties of biodiesel from algal oils are predicted with cetane numbers expected in the low to upper 40s and kinematic viscosity between 3 and 4 mm(2)/s for most algal biodiesel.
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  398. H-1 Nuclear Magnetic Resonance (NMR) Determination of the Iodine Value in Biodiesel Produced from Algal and Vegetable Oils
    Abstract

    Kumar, R.; Bansal, V.; Patel, M. B.; Sarpal, A. S. 2012. H-1 Nuclear Magnetic Resonance (NMR) Determination of the Iodine Value in Biodiesel Produced from Algal and Vegetable Oils. Energy & Fuels. 26(11) 7005-7008

    A method for the determination of the iodine value in biodiesel produced from algal and vegetable oils has been developed by nuclear magnetic resonance (NMR) spectroscopy. The determination of the Iodine: Value is based on the average molecular weight of the fatty acid methyl ester and the number of double bond, which are calculated from H-1 NMR spectra. The total methyl ester content (% ME) was estimated using the integral Value of the OCH3 group peak at 3.67 ppm and the alpha CH2 at 2.2 ppm. The results obtained from the H-1 NMR method show good correlation (r(2) = 0.9974) with the traditional American Oil Chemists' Society (AOCS) method. The H-1 NMR method does not depend upon the nature of biodiesel feedstock. It is applicable to all methyl biodiesel samples obtained from different raw materials including algal oils. The results show that a higher iodine value indicates less oxidation stability, but there is not a linear correlation between the iodine value and oxidation stability of biodiesel.
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  399. High Lipid Induction in Microalgae for Biodiesel Production
    Abstract

    Sharma, K. K.; Schuhmann, H.; Schenk, P. M. 2012. High Lipid Induction in Microalgae for Biodiesel Production. Energies. 5(5) 1532-1553

    Oil-accumulating microalgae have the potential to enable large-scale biodiesel production without competing for arable land or biodiverse natural landscapes. High lipid productivity of dominant, fast-growing algae is a major prerequisite for commercial production of microalgal oil-derived biodiesel. However, under optimal growth conditions, large amounts of algal biomass are produced, but with relatively low lipid contents, while species with high lipid contents are typically slow growing. Major advances in this area can be made through the induction of lipid biosynthesis, e.g., by environmental stresses. Lipids, in the form of triacylglycerides typically provide a storage function in the cell that enables microalgae to endure adverse environmental conditions. Essentially algal biomass and triacylglycerides compete for photosynthetic assimilate and a reprogramming of physiological pathways is required to stimulate lipid biosynthesis. There has been a wide range of studies carried out to identify and develop efficient lipid induction techniques in microalgae such as nutrients stress (e.g., nitrogen and/or phosphorus starvation), osmotic stress, radiation, pH, temperature, heavy metals and other chemicals. In addition, several genetic strategies for increased triacylglycerides production and inducibility are currently being developed. In this review, we discuss the potential of lipid induction techniques in microalgae and also their application at commercial scale for the production of biodiesel.
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  400. Immobilization as a feasible method to simplify the separation of microalgae from water for biodiesel production
    Abstract

    Lam, M. K.; Lee, K. T. 2012. Immobilization as a feasible method to simplify the separation of microalgae from water for biodiesel production. Chemical Engineering Journal. 191263-268

    In the present study, the use of immobilization technology to cultivate microalgae in entrapped matrix gel beads was demonstrated. Since the gel beads are denser in water, the beads can be easily collected through simple filtration method and hence, simplifying the overall separation process. Various parameters were investigated to optimize the growth rate of immobilized microalgae and the optimum conditions were obtained as: alginate to microalgae volume ratio of 0.3, Ca2+ concentration of 2%, organic nutrients concentration of 50 mL (equivalent to 13.09 mg/L nitrate), initial culture pH of 4 and photoperiod of 24 h. Using this optimum culture condition, 0.50 mg biomass/bead was attained on the 10th clay of cultivation. Apart from that, this study also attempted to co-immobilize nutrients into microalgae beads in order to minimize free cell culture (microalgae cells that are released into the culture medium due to rupturing of beads) and to reduce water consumption. Through this approach, it was found that microalgae biomass yield increased to 0.67 mg/bead within a shorter culturing time (5 days) with insignificant amount of free cell culture detected. Furthermore, lipid extracted from immobilized microalgae biomass has high potential for biodiesel production clue to the similarity of fatty acid profile with other oil bearing crops. (c) 2012 Elsevier B.V. All rights reserved.
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  401. Integrating LCA and Thermodynamic Analysis for-Sustainability Assessment of Algal Biofuels: Comparison of Renewable Diesel vs. Biodiesel
    Abstract

    Borkowski, M. G.; Zaimes, G. G.; Khanna, V. 2012. Integrating LCA and Thermodynamic Analysis for-Sustainability Assessment of Algal Biofuels: Comparison of Renewable Diesel vs. Biodiesel. 2012 Ieee International Symposium on Sustainable Systems and Technology (Issst).

    Advanced biofuels are attracting intense interest from government, industry and researchers as potential substitutes for petroleum gasoline and diesel transportation fuels. Microalgae's advantages as a biofuel feedstock are due particularly to their rapid growth rates and high lipid content. Several life cycle analysis (LCA) studies have been conducted on the production of biodiesel, however less attention has been paid to algae-derived green diesel (renewable diesel II), a promising alternative fuel product. Renewable diesel's advocates suggest that it has superior energy density, shelf stability and can function as a drop-in replacement for petroleum diesel due to their similar chemical composition and fuel properties. Fewer studies have attempted to quantify the sustainability of algae-derived renewable diesel, though renewable diesel options are examined in the current GREET model. This study conducts a well-to-pump LCA focusing on this Renewable Diesel II (RD2) upgrade pathway and comparing it with the corresponding pathway from algal biomass to biodiesel. Particular attention is paid to primary energy use and fossil energy ratio (FER), greenhouse gas emissions, and an initial investigation of thermodynamic metrics. While hydrotreating is less than half as energy intensive a fuel upgrade process as transesterification, the overall life-cycle energy consumption and greenhouse gas emissions are found to be nearly equal for renewable diesel and biodiesel. The complete biofuel production process is only found to be net energy positive for scenarios with reduced burdens from both CO2 sourcing and biomass drying.
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  402. Investigation of utilization of the algal biomass residue after oil extraction to lower the total production cost of biodiesel
    Abstract

    Gao, M. T.; Shimamura, T.; Ishida, N.; Takahashi, H. 2012. Investigation of utilization of the algal biomass residue after oil extraction to lower the total production cost of biodiesel. Journal of Bioscience and Bioengineering. 114(3) 330-333

    In this study, component analysis of a novel biodiesel-producing alga, Pseudochoricystis ellipsoidea, was performed. The component analysis results indicated that proteins and amino acids are abundant in P. ellipsoidea while the sugar content is relatively low. Rather than its use as a carbon source, the use of the algal biomass residue after oil extraction as a nutrient source provided a new way for lowering the total production cost of biodiesel. In both lactic acid and ethanol fermentations, the use of the residue instead of high-cost nutrient yeast extract allowed a significant saving, showing the promise of the algal biomass residue for use as a fermentation nutrient source. (C) 2012, The Society for Biotechnology, Japan. All rights reserved.
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  403. Investigations on microalgal oil production from Arthrospira platensis: towards more sustainable biodiesel production
    Abstract

    Baunillo, K. E.; Tan, R. S.; Barros, H. R.; Luque, R. 2012. Investigations on microalgal oil production from Arthrospira platensis: towards more sustainable biodiesel production. Rsc Advances. 2(30) 11267-11272

    Microalgae have emerged as one of the most promising sources for biodiesel production. Arthrospira platensis (Spirulina) is known for its nutritional benefits with very low lipid content. However, among all other algae, spirulina is the most easy to cultivate due to its inherent resistance to contamination and environmental changes. The presented work aims to determine the best culture medium to achieve an optimum lipid content for microalgae in view of a subsequent exploration for biodiesel production. This was conducted by means of a two step microalgal oil extraction followed by a conventional acid-catalysed esterification of the released fatty acids. Algal growth, biomass and lipid content were compared for Spirulina grown under six different culture media. 1) culture medium of complete nutrition (CONTROL); 2) nitrogen and phosphorus-deprived [NP(-)]; 3) nitrogen-deprived [N(-)]; 4) phosphorus-deprived [P(-)]; 5) nitrogen and phosphorus-limited [NPL] and; 6) nitrogen-deprived and phosphorus-limited [N(-)PL]. With the minimum possible dried biomass (0.4780 g L-1), the largest lipid content (ca. 20%) was achieved in spirulina grown under nitrogen-deprived and phosporous-limited conditions [N(-) PL]. Dried biomass from Spirulina grown under two opposite culture media: complete nutrition [CONTROL]; and nitrogen and phosphorous deprived [NP(-)], were utilised for biodiesel preparation after oil extraction. A crude biodiesel yield of 40% and 42%, with a FAME content of 69% and 55% were obtained for CONTROL and NP(-) samples, respectively. Interestingly, the nutrient condition of Spirulina did influence biodiesel yields but not significantly their FAME compositions, which comprised of mostly C16:0 and C18:2, similar to that of conventional biodiesel.
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  404. Key issues to consider in microalgae based biodiesel production
    Abstract

    Singh, A.; Pant, D.; Olsen, S. I.; Nigam, P. S. 2012. Key issues to consider in microalgae based biodiesel production. Energy Education Science and Technology Part a-Energy Science and Research. 29(1) 687-700

    All nations have been confronted with the energy crisis due to depletion of finite fossil fuels reserves, which results an increasing global demand of biofuels for energy security, economic stability and reduction in climate change effects, and generate the opportunity to explore new biomass sources. The production of sustainable bioenergy is a challenging task in the promotion of biofuels for replacing the fossil based fuels to mitigate challenges of fossil based energy consumption. Algae might be a very promising source of biomass in this context as it sequesters a significant quantity of carbon from atmosphere and industrial gases and is also very efficient in utilizing the nutrients from industrial effluents and municipal wastewater. If developed sustainably, the algae biofuel industry may be able to provide large quantities of biofuels with potentially minimal environmental impacts. However, in order to realize this, a complete analysis of full life cycle impact of algal biofuel production in the context of issues such as water resource management, land use impact, energy balance and air emissions are very necessary. The commercial-scale production of algae requires careful consideration of many issues that can be broadly categorized into four main areas: selecting algae species that produce high oil levels and grow well in specified environments, algae growth methods, water sources and related issues, and nutrient and growth inputs.
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  405. Large-scale biodiesel production using microalgae biomass of Nannochloropsis
    Abstract

    Moazami, N.; Ashori, A.; Ranjbar, R.; Tangestani, M.; Eghtesadi, R.; Nejad, A. S. 2012. Large-scale biodiesel production using microalgae biomass of Nannochloropsis. Biomass & Bioenergy. 39449-453

    The aim of this study is to investigate the large-scale algae production using Nannochloropsis sp. in indoor open ponds. One of the key factors in open pond productivity is the uniformity of distribution of nutrients and CO2. Therefore, the effects of paddlewheel speeds (1.4, 2.1 and 2.8 rad s (1)) on the productivity were also evaluated. The culture system used in the experiment consisted of three raceway ponds of 2000-L capacity each. Other parameters such as growth medium (seawater), illumination (150 mu mol m (2) s(-1)), pH (7.5 +/- 0.2), water level (30 cm), and temperature (25 degrees C) were kept constant during the two weeks experiments. In general, the results revealed that higher lipid content and biomass can be obtained by varying paddlewheel speeds. With increase in impeller speed from 1.4 to 2.1 rad s(-1) the biomass productivity significantly increased, which indicates that microalgae could access more nutrients, CO2 and illumination. The maximum growth of 46 g L-1 m(-2) and lipid content of 52% were obtained after 14 days with 2.1 rad s (1). The amount of hydrocarbon was varied from 55 to 70 mg L-1 day(-1) cell weight, showing the best combination of biomass productivity and lipid content in indoor conditions. The present study showed the best combination of biomass productivity and lipid content in indoor conditions. (C) 2012 Elsevier Ltd. All rights reserved.
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  406. Life cycle assessment (LCA) for greenhouse gas (GHG) emissions from microalgae biodiesel production
    Abstract

    Woertz, I.; Du, N.; Rhodes, J.; Mendola, D.; Mitchell, G.; Lundquist, T.; Benemann, J. 2012. Life cycle assessment (LCA) for greenhouse gas (GHG) emissions from microalgae biodiesel production. Abstracts of Papers of the American Chemical Society. 243

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  407. Life Cycle Assessment of Biodiesel Production from Microalgae in Thailand: Energy Efficiency and Global Warming Impact Reduction
    Abstract

    Wibul, P.; Malakul, P.; Pavasant, P.; Kangvansaichol, K.; Papong, S. 2012. Life Cycle Assessment of Biodiesel Production from Microalgae in Thailand: Energy Efficiency and Global Warming Impact Reduction. Pres 2012: 15th International Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction. 291183-1188

    In this study, a life cycle assessment (LCA) technique based on ISO 14040 series was performed to evaluate biodiesel production from freshwater microalgae Scenedesmus armatus in terms of energy efficiency (Net Energy Ratio or NER) and environmental impact (Global Warming Potential or GWP). The system boundary covered the entire life cycle of microalgae-based biodiesel, which was divided into four distinct steps: cultivation, harvesting, oil extraction, and transesterification. Based on a functional unit of 1 MJ biodiesel, NER was found to be 0.34 and 0.19 for mass allocation and energy allocation, respectively. This energy deficit (NER< 1) for both allocation methods was due to the high energy input required to culture microalgae. However, CO2 uptake in biomass agriculture leads to better performance in global warming potential (GWP) when compared to conventional diesel and biodiesel produced from rapeseed and soybean. This is a result of the cultivation process in which microalgae can fix up to 25 % of net greenhouse gas emissions (kg CO2 equivalent). Sensitivity analysis showed that increasing in biomass concentration can improve not only net energy ratio (NER) but also global warming potential (GWP).
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  408. Materials flow modeling of nutrient recycling in biodiesel production from microalgae
    Abstract

    Rosch, C.; Skarka, J.; Wegerer, N. 2012. Materials flow modeling of nutrient recycling in biodiesel production from microalgae. Bioresource Technology. 107191-199

    Biodiesel production based on microalgae as feedstock is associated with a high demand of nutrients, respectively nitrogen and phosphorus. The production of 1l biodiesel requires between 0.23 and 1.55 kg nitrogen and 29-145 g of phosphorus depending of the cultivation conditions for microalgae. The supply of nutrients can be expected to severely limit the extent to which the production of biofuels from microalgae can be sustainably expanded. The nutrient demand can be reduced if the nutrients in the residual algae biomass after oil extraction are reused for algae cultivation. This modeling work illustrates that for the investigated process chains and scenarios the nutrient recycling rates are in the range from 30% to 90% for nitrogen and from 48% to 93% for phosphorus. The highest recycling values can be achieved by hydrothermal gasification of the oil-free residues. (C) 2011 Elsevier Ltd. All rights reserved.
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  409. Microalgae Based Biorefinery: Evaluation of Several Routes for Joint Production of Biodiesel, Chlorophylls, Phycobiliproteins, Crude Oil and Reducing Sugars
    Abstract

    Gonzalez-Delgado, A. D.; Kafarov, V. 2012. Microalgae Based Biorefinery: Evaluation of Several Routes for Joint Production of Biodiesel, Chlorophylls, Phycobiliproteins, Crude Oil and Reducing Sugars. Pres 2012: 15th International Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction. 29607-612

    In this work, several routes for obtaining high value pigments, fermentable sugars, crude algae oil and biodiesel were evaluated using the microalgae strain Amphiprora sp. in order to develop a topology of microalgae-based biorefinery. For chlorophylls and phycobiliproteins extraction, ethanol and methanol were evaluated as solvents, for reducing sugars production, Organosolv pretreatment (OSE), acid hydrolysis (HSE), and multifunctional systems using ethanol (MSE) and methanol (MSM) were compared. For lipid extraction, five solvent-based methods were compared with multifunctional process and for biodiesel production, transesterification, MSE and MSM were used. Results shows that several bioproducts can be obtained from Amphiprora sp. microalgae and can be a promissory strain for the development of a biorefinery, two routes were defined: one route without the use of multifunctional processes with includes pigments extraction using ethanol, reducing sugars production by organosolv pretreatment, lipid extraction by HBE method and oil transesterification by methanol/NaOH; and a second route composed by pigments extraction using ethanol, multifunctional process by MSE route and biodiesel production from algae oil by methanol/NaOH transesterification.
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  410. Microalgae Isolation and Selection for Prospective Biodiesel Production
    Abstract

    Duong, V. T.; Li, Y.; Nowak, E.; Schenk, P. M. 2012. Microalgae Isolation and Selection for Prospective Biodiesel Production. Energies. 5(6) 1835-1849

    Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products are now being considered for commercial production which necessitates the selection of the most capable algae strains suitable for multiple-product algae biorefineries. Here we present and review practical issues of several simple and robust methods for microalgae isolation and selection for traits that maybe most relevant for commercial biodiesel production. A combination of conventional and modern techniques is likely to be the most efficient route from isolation to large-scale cultivation.
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  411. Microalgae processing for biodiesel production
    Abstract

    Mata, T. M.; Martins, A. A.; Caetano, N. S. 2012. Microalgae processing for biodiesel production. Advances in Biodiesel Production: Processes and Technologies. (39) 204-231

    Microalgae are increasingly seen as a potential alternative to traditional feedstocks for biodiesel, which are limited and may have economic, social and environmental impacts. However, processing microalgae for biofuels is remarkably different and poses significant challenges in ensuring that they are competitive when compared with the other feedstocks. This article describes and critically analyses the main aspects and methods that can be used for the downstream processing of microalgae for biodiesel production. A brief analysis is made of the current and potential biodiesel production processes from microalgae, focusing on their main advantages and problems. The biorefinery concept is also discussed, that is, how microalgae biomass can be used to produce not just biodiesel but also other biofuels and/or high value bio-products and what will enable the economic sustainability of the whole process to be increased.
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  412. Microalgal biodiesel and the Renewable Fuel Standard's greenhouse gas requirement
    Abstract

    Soratana, K.; Harper, W. F.; Landis, A. E. 2012. Microalgal biodiesel and the Renewable Fuel Standard's greenhouse gas requirement. Energy Policy. 46498-510

    The Renewable Fuel Standard (RFS2) under the Energy Independence and Security Act of 2007 requires 15.2 billion gallons of domestic alternative fuels per year by 2012, of which 2 billion gallons must be from advanced biofuel and emit 50% less life-cycle greenhouse gas (GHG) emissions than petroleum-based transportation fuels. Microalgal biodiesel, one type of advanced biofuel, has the qualities and potential to meet the RFS's requirement. A comparative life cycle assessment (LCA) of four microalgal biodiesel production conditions was investigated using a process LCA model with Monte Carlo simulation to assess global warming potential (GWP), eutrophication, ozone depletion and ecotoxicity potentials. The four conditions represent minimum and maximum production efficiencies and different sources of carbon dioxide and nutrient resources, i.e. synthetic and waste resources. The GWP results of the four CO2 microalgal biodiesel production conditions showed that none of the assumed production conditions meet the RFS's GHG requirement. The GWP results are sensitive to energy consumption in harvesting process. Other impacts such as eutrophication, ozone depletion and ecotoxicity potentials, are sensitive to percent lipid content of microalgae, service lifetime of PBRs and quantity of hexane in extraction process, respectively. Net energy ratio and other emissions should be included in future RFS for a more sustainable fuel. (C) 2012 Elsevier Ltd. All rights reserved.
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  413. Microalgal culture in photo-bioreactor for biodiesel production: case studies from Egypt
    Abstract

    El-Ardy, O.; El-Enin, S. A. A.; El Semary, N. A.; El Diwani, G. 2012. Microalgal culture in photo-bioreactor for biodiesel production: case studies from Egypt. Afinidad. 69(558) 137-143

    Biodiesel production from three local microalgae from Egypt was investigated. These microalgae strains differ in their growth pattern as one of the cyanobacterial strains is filamentous mat-forming Phormidium sp. whereas the other strain is coccoid colony-forming Microcystis sp. The third is coccoid yellow-green Botrydiopsis sp. The mass productivity for the strains in a photobioreactor using semi-continuous culture was arranged as: Microcystis sp.> Botrydiopsis sp.> Phormidium sp. The mass productivity can be increased by increasing the illumination period in case of Botrydiopsis sp. and Microcystis sp. The lipid content was determined by using different solvents for lipid extraction. The Botrydiopsis sp. gave the highest lipid content (48%) for Botrydiopsis sp. cultured in Oscillatoria medium. Microcystis sp. had (28%) lipid content while the Phormidium sp. had the lowest lipid content (15%). The major components of the fatty acid compositions in different algal species studied were linoleic, palmitic, oleic and stearic. In conclusion, the cultivation of microalgae in photo-bioreactor has given high biomass productivity by applying semi-continuous feeding technique. The highest mass productivity doesn't mean the highest lipid content. The Gas chromatography analysis showed that the algae oils have the suitable fatty acid composition for biodiesel production.
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  414. Microalgal fatty acid composition: implications for biodiesel quality
    Abstract

    Stansell, G. R.; Gray, V. M.; Sym, S. D. 2012. Microalgal fatty acid composition: implications for biodiesel quality. Journal of Applied Phycology. 24(4) 791-801

    The fuel properties of microalgal biodiesel are predicted using published microalgal fatty acid (FA) compositions and predictive fuel models. Biodiesels produced from the microalgae investigated are predicted to have extremely poor oxidative stabilities and the majority also have poor cold-flow properties. The cetane number in most cases is out of specification, but less so than the oxidative stability and cold flow. These findings support the idea that feedstocks rich in monounsaturated fatty acids (MUFAs) are desirable for biodiesel but the composition of the saturated fatty acids (SFAs) is also shown to be of great importance. There is an apparent relationship between algal class and the percentage of FAs represented by MUFA. This potentially allows for the identification of high-MUFA algal classes, or at least provides some basis for researchers to make initial selections of target classes for bioprospecting. Comparisons of FA groups between algal classes also show that the SFAs of Mediophyceae contain significantly higher proportions of C14:0, which is in contrast to the normally abundant C16:0 and the Mediophyceae therefore have better cold-flow characteristics than other classes with similar total SFA contents. Certain particularly promising cases for biodiesel production are presented as species level examples of feedstocks that are close to satisfying the biodiesel standards and to further illustrate the challenges that remain. Variation in FA composition as a response to changes in certain environmental variables forms another important facet to feedstock selection and is briefly considered, with suggestions for further research.
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  415. Microwave Irradiation Application in Biodiesel Production from Promising Biodiesel Feedstock: Microalgae (Chlorella protothecoides)
    Abstract

    Azcan, N.; Yilmaz, O. 2012. Microwave Irradiation Application in Biodiesel Production from Promising Biodiesel Feedstock: Microalgae (Chlorella protothecoides). World Congress on Engineering and Computer Science, Wcecs 2012, Vol Ii. 737-742

    Microwave irradiation effect on transesterification reaction of the new generation biofuel resource, microalgae, was studied. Experiments were conducted in order to evaluate the effects of reaction variables such as catalyst amount (1-1.5% w/w), oil:methanol molar ratio (1:6-1:10), and time (5-20 min) on methyl ester content of biodiesel. A comparative study on heating system was performed to show energy-efficiency of microwave-accelerated transesterification reaction. Suitable transesterification reaction conditions were determined as 65 degrees C, 1 wt.% KOH, 5 min, 1:8 microalgae oil:methanol molar ratio using microwave heating system. At these conditions fatty acid methyl ester content was determined as 96.54%. The results show that microwave heating has effectively reduced the reaction time from 210 min to 5 min.
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  416. On the concept of the future drinking water treatment plant: algae harvesting from the algal biomass for biodiesel production-a review
    Abstract

    Ghernaout, D.; Ghernaout, B. 2012. On the concept of the future drinking water treatment plant: algae harvesting from the algal biomass for biodiesel production-a review. Desalination and Water Treatment. 49(1-3) 1-18

    It is well established that the drinking water treatment has several disadvantages such as it may rupture the algae, thereby releasing the taste- and odour-producing oils before the whole algae are removed from the treatment system. This review aims to present the concept of algae recovery instead of its removal in drinking water treatment plant. Control of algae in water supplies and some coagulation/flocculation and electrolysis experiments as harvesting methods are discussed. In fact, algae recovery instead of its removal in water treatment plant is a promising perspective and a suitable issue when the surface water comes from dams where algae blooms occur frequently. Micro-algae are a sustainable energy resource with great potential for CO2 fixation. The micro-algae could be grown in photo-bioreactors or in open ponds. A new interesting field of research would be fast and simultaneous algal biodiesel production with drinking water treatment in the biodiesel production/water treatment plant without chemicals. However, the fact that algal cultivation needs light and space would be very difficult challenge.
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  417. Optimizing net energy gain in algal cultivation for biodiesel production
    Abstract

    Arudchelvam, Y.; Nirmalakhandan, N. 2012. Optimizing net energy gain in algal cultivation for biodiesel production. Bioresource Technology. 114294-302

    An approach based on energy gain was utilized to optimize algal cultivation in bubble columns. Net energy gain was estimated considering the energy input for mixing and providing carbon dioxide, and the energy that can be generated from the lipids extracted from the algal biomass. Energy input for sparging was minimized based on the gas-to-culture volume ratio and energy output from lipid production was maximized based on nitrate and CO2 levels. Sparging at a gas-to-culture volume ratio of 0.18 min(-1) with CO2-enrichment of 0.5% and initial nitrate concentration of 1 mM was optimal for improving net energy gain with Nannochloropsis sauna. Sparging with CO2-enriched air of 0.5% along with nitrogen starvation resulted in 50% more lipid productivity than sparging with ambient air. (C) 2012 Elsevier Ltd. All rights reserved.
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  418. Power dissipation in microwave-enhanced in situ transesterification of algal biomass to biodiesel
    Abstract

    Patil, P. D.; Reddy, H.; Muppaneni, T.; Mannarswamy, A.; Schuab, T.; Holguin, F. O.; Lammers, P.; Nirmalakhandan, N.; Cooke, P.; Deng, S. G. 2012. Power dissipation in microwave-enhanced in situ transesterification of algal biomass to biodiesel. Green Chemistry. 14(3) 809-818

    We investigated the effect of power dissipation on microwave-accelerated simultaneous extraction and transesterification of dry algal biomass (Nannochloropsis salina) to biodiesel. The response surface methodology (RSM) was applied to design the experiments and optimize the process parameters, including dry algae to methanol ratio, reaction time and catalyst concentrations, by evaluating their influences on the fatty acid methyl ester yield (FAME) under controlled microwave power conditions. The microwave energy utilization efficiency was estimated at various power levels to optimize the power dissipation, maximize FAME yields and minimize energy losses. The algal biomass characterization and algal biodiesel analysis were performed using various analytical instruments such as FTIR, SEM-EDS, TGA and GC-MS. The Nile Red method was applied for lipid localization in microalgae cells using confocal microscopy and fluorescence spectroscopy. The direct conversion technique has the potential to provide energy-efficient and economical routes for biodiesel production from algal biomass.
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  419. Production of MHD Power from Municipal Waste & Algal Biodiesel
    Abstract

    Habib, S.; Haque, A.; Rahman, J. 2012. Production of MHD Power from Municipal Waste & Algal Biodiesel. 2012 Ieee Power and Energy Society General Meeting.

    This paper presents our endeavor to establish a feasible renewable energy power plant in Bangladesh. Our primary energy source is the municipal waste in Dhaka city. The organic compounds present in waste produces biomethane by anaerobic digestion. But the combustion of this gas emits harmful CO2. To reduce emissions substantially, an algae pond is proposed where the exhaust carbon dioxide is sequestered yielding algae growth. But algae appears to be a potential producer of biodiesel and biomethane; so it secondary source of renewable energy for our power production. The generator used for producing electricity works on the principle of magneto hydrodynamics (MHD). Input to our MHD generator is the thermal energy obtained from combustion of the renewable biomethane & biodiesel.
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  420. Reduction of environmental and energy footprint of microalgal biodiesel production through material and energy integration
    Abstract

    Chowdhury, R.; Viamajala, S.; Gerlach, R. 2012. Reduction of environmental and energy footprint of microalgal biodiesel production through material and energy integration. Bioresource Technology. 108102-111

    The life cycle impacts were assessed for an integrated microalgal biodiesel production system that facilitates energy- and nutrient-recovery through anaerobic digestion, and utilizes glycerol generated within the facility for additional heterotrophic biodiesel production. Results show that when external fossil energy inputs are lowered through process integration, the energy demand, global warming potential (GWP), and process water demand decrease significantly and become less sensitive to algal lipid content. When substitution allocation is used to assign additional credit for avoidance of fossil energy use (through utilization of recycled nutrients and biogas), GWP and water demand can, in fact, increase with increase in lipid content. Relative to stand-alone algal biofuel facilities, energy demand can be lowered by 3-14 GJ per ton of biodiesel through process integration. GWP of biodiesel from the integrated system can be lowered by up to 71% compared to petroleum fuel. Evaporative water loss was the primary water demand driver. (c) 2011 Elsevier Ltd. All rights reserved.
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  421. Releasing stored solar energy within pond scum: Biodiesel from algal lipids
    Abstract

    Blatti, J. L.; Burkart, M. D. 2012. Releasing stored solar energy within pond scum: Biodiesel from algal lipids. Abstracts of Papers of the American Chemical Society. 243

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  422. Research on KOH/La-Ba-Al2O3 catalysts for biodiesel production via transesterification from microalgae oil
    Abstract

    Zhang, X. Y.; Ma, Q.; Cheng, B. B.; Wang, J.; Li, J. S.; Nie, F. D. 2012. Research on KOH/La-Ba-Al2O3 catalysts for biodiesel production via transesterification from microalgae oil. Journal of Natural Gas Chemistry. 21(6) 774-779

    Alumina supports modified by lanthanum (La) and barium (Ba) were prepared by peptization. Catalysts with different KOH contents supported on modified alumina were prepared by impregnation method. Various techniques, including N-2 adsorption-desorption (Brunauer-Emmet-Teller method, BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and fourier transform infrared absorption spectroscopy (FT-IR). Catalytic activity for microalgae oil conversion to methyl ester via transesterification was evaluated and analyzed by GC-MS and GC. BET results showed that the support possessed high specific surface area, suitable pore volume and pore size distribution. Activity results indicated that the catalyst with 25 wt% KOH showed the best activity for microalgae oil conversion. XRD and SEM results revealed that Al-O-K compound was the active phase for microalgae oil conversion. The agglomeration and changing of pore structure should be the main reasons for the catalyst deactivation when KOH content was higher than 30 wt%.
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  423. Simultaneous Optimization and Heat Integration for Biodiesel Production from Cooking Oil and Algae
    Abstract

    Martin, M.; Grossmann, I. E. 2012. Simultaneous Optimization and Heat Integration for Biodiesel Production from Cooking Oil and Algae. Industrial & Engineering Chemistry Research. 51(23) 7998-8014

    In this article, we address the optimal production of second-generation biodiesel using waste cooking oil and algae oil. We consider five different technologies for the transesterification of the oil (homogeneous acid- or alkali-catalyzed, heterogeneous basic-catalyzed, enzymatic, and supercritical uncatalyzed). We formulate the problem as an MINLP problem where the models for each of the reactors are based on surface response methodology to capture the effects of the variables on the yield. The aim is to perform simultaneous optimization and heat integration for the production of biodiesel from each of the different oil sources in terms of the technology to use and the operating conditions to apply. Furthermore, a process network is designed to minimize the freshwater consumption. The optimal conditions in the reactors differ from those traditionally used because the separation tasks are taken into account in this work. For algae oil, the optimal process employs alkali as the catalyst and has a production cost of 0.42$/gal, an energy consumption of 1.94 MJ/gal, and a freshwater consumption of 0.60 gal(water)/gal(ethanol). For cooking oil, the optimal process is the one with the heterogeneous catalyst and has a production cost and energy and water consumption of $0.66/gal, 1.94 MJ/gal, and 0.33 gal(water)/gal(ethanol), respectively.
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  424. Supercritical carbon dioxide extraction of algal lipids for the biodiesel production
    Abstract

    Santana, A.; Jesus, S.; Larrayoz, M. A.; Filho, R. M. 2012. Supercritical carbon dioxide extraction of algal lipids for the biodiesel production. Chisa 2012. 421755-1761

    Biodiesel production from algae is a promising technique. Microalgae are able to accumulate fatty acids up to 50% of their dry weight when submitted to nitrogen defaults. They are then expected to be a new potential renewable source of biodiesel. Efficiently extracting algae oil from microalgae plays an important role in the development of microalgae biofuel. Algae bio-oil is traditionally obtained using thermal liquefaction or pyrolysis, and they may be obtained after an extraction using organic solvents as hexane. Such methods have some drawbacks like inherent toxicity, poor selectivity, difficult separation of the contaminants as well as solvents from the desired product, energy consuming and pollutant. Supercritical carbon dioxide extraction is a promising green technology that can potentially displace the use of traditional organic solvents for lipid extraction. The supercritical fluid extraction has several advantages when compared to traditional extraction method (hexane, petroleum ether, chloroform/ethanol) used for obtaining lipids from algae, in which supercritical extraction provide higher selectivities, shorter extraction time and do not use toxic organic solvents. This study examines the performace of supercritical carbon dioxide extraction of lipids from Botryococcus braunii for biodiesel production. The experiments were conducted at temperatures of 50 - 80 degrees C, pressure from 200 to 250 bar. The evolution of the process was followed by gas chromatography, determining the concentration of the fatty acids at different reaction times. For supercritical carbon dioxide extraction, lipid yield was found to decrease with temperature and to increase with pressure. Relatively high recovery of polyunsaturated fatty acids and essential fatty acids in supercritical fluid extracted algal lipids were observed. The optimum operating conditions for a supercritical extraction were pressure between 220-250 bar and temperature of 50 degrees C. This research is part of a wider experimental project involving the supercritical carbon dioxide extraction of lipids from microalgae to contribute to the development of algal lipids into a variable energy source by optimizing lipid extraction techniques for efficiency, sustainability, decreased hazard, and selectivity, focusing on the use of supercritical fluids as alternative green solvents. (C) 2012 Published by Elsevier Ltd.
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  425. Sustainability assessment of microalgal biodiesel production processes: an exergetic analysis approach with Aspen Plus
    Abstract

    Ofari-Boateng, C.; Lee, K. T.; Lim, J. 2012. Sustainability assessment of microalgal biodiesel production processes: an exergetic analysis approach with Aspen Plus. International Journal of Exergy. 10(4) 400-416

    Biodiesel production growth rate keeps increasing every year with the hope of replacing fossil based liquid fuel which is near exhaustion. Energy efficiency methods coupled with environmental and economic sustainabilities would render biodiesel production attractive. Algal cultivation and oil extraction processes are found to be energy intensive hence exergy destructive. This study presents the thermodynamic feasibility of microalgal biodiesel production plant via exergy analysis. Mathematical modelling withAspen Plus shows that the centrifuge for algae-medium separation recorded the highest exergy loss of 925 MJ representing 15% of the total exergy loss. 64% of the total exergy input into the whole plant is destroyed to attain the products (biodiesel and glycerin).
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  426. The feasibility of biodiesel production by microalgae using industrial wastewater
    Abstract

    Wu, L. F.; Chen, P. C.; Huang, A. P.; Lee, C. M. 2012. The feasibility of biodiesel production by microalgae using industrial wastewater. Bioresource Technology. 11314-18

    This study investigated nitrogen and phosphorus assimilation and lipid production of microalgae in industrial wastewater. Two native strains of freshwater microalgae were evaluated their biomass growth and lipid production in modified BBM medium. Chlamydomonas sp. TAI-2 had better biomass growth and higher lipid production than Desmodesmus sp.TAI-1. The optimal growth and lipid accumulation of Chlamydomonas sp. TAI-2 were tested under different nitrogen sources, nitrogen and CO2 concentrations and illumination period in modified BBM medium. The optimal CO2 aeration was 5% for Chlamydomonas sp. TAI-2 to achieve maximal lipid accumulation under continuous illumination. Using industrial wastewater as the medium, Chlamydomonas sp. TAI-2 could remove 100% NH4+-N (38.4 mg/L) and NO3--N (3.1 mg/L) and 33% PO43--P (44.7 mg/L) and accumulate the lipid up to 18.4%. Over 90% of total fatty acids were 14:0, 16:0, 16:1, 18:1, and 18:3 fatty acids, which could be utilized for biodiesel production. (C) 2011 Elsevier Ltd. All rights reserved.
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  427. A parametric study of electrocoagulation as a recovery process of marine microalgae for biodiesel production
    Abstract

    Uduman, N.; Bourniquel, V.; Danquah, M. K.; Hoadley, A. F. A. 2011. A parametric study of electrocoagulation as a recovery process of marine microalgae for biodiesel production. Chemical Engineering Journal. 174(1) 249-257

    Microalgal biomass as feedstock for biofuel production is rapidly gaining appreciation in response to the increasing petroleum prices and the upsurge in global warming concerns. However, the process of creating concentrated biomass from microalgal cultures is limited by ineffective dewatering procedures. The economics of existing culture clarification unit operations make the process of creating biomass from microalgae unattractive for biofuel development. This work involves the comparison of the removal efficiency (recovery) of two marine microalgae species Chlorococcum sp. and Tetraselmis sp. by electrocoagulation (EC), a technique that has not been thoroughly explored in marine microalgae dewatering. High recovery efficiencies were obtained of up to 99 and 98% for Tetraselmis sp. and Chlorococcum sp., respectively. The effect of culture temperature and salinity on removal efficiency was also observed. A starting temperature of 60 degrees C resulted in optimal recovery values of 96 and 94% for Chlorococcum sp. and Tetraselmis sp., respectively. Whereas a starting temperature of 5 degrees C achieved optimal recovery of only Sand 68% for Chlorococcum sp. and Tetraselmis sp., respectively. Increased salinity of microalgae culture showed increased microalgae recovery. Salinity of 20% gave optimal microalgae recovery values of only 6 and 9% for Chlorococcum sp. and Tetraselmis sp., respectively. Zeta potential (ZP) analysis was carried out to verify and further understand the charge neutralization mechanism due to Fe(2+) cations. (C) 2011 Elsevier B.V. All rights reserved.
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  428. A review of enzymatic transesterification of microalgal oil-based biodiesel using supercritical technology
    Abstract

    Taher, H.; Al-Zuhair, S.; Al-Marzouqi, A. H.; Haik, Y.; Farid, M. M. 2011. A review of enzymatic transesterification of microalgal oil-based biodiesel using supercritical technology. Enzyme Res. 2011468292

    Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO(2)) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO(2) as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO(2) allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO(2) as an extraction solvent and reaction media.
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  429. Algae Biofuels as a Possible Alternative to Environmentally Doubtful Conventional Methods of Biodiesel Production
    Abstract

    Kurevija, T.; Kukulj, N. 2011. Algae Biofuels as a Possible Alternative to Environmentally Doubtful Conventional Methods of Biodiesel Production. Survival and Sustainability: Environmental Concerns in the 21st Century. 499-510

    In last 10 years there was significant rise in transportation fuel consumption in Europe from 180 Mt in 1985. to 270 Mt in 2004., with gasoline representing 40% and diesel 60%. To decrease dependence upon imported fossil fuels, EU aim is to introduce biodiesel in share of 5.75% in transportation sector until 2010. and finally 8% until 2020. Because of limited production potential from some EU countries, today and in near future, large quotas of import would be required. Biodiesel is often called clean, ecological and renewable alternative fuel, but with present land-intensive methods of production it could easily be named as one of the most dangerous sources of energy for Earth's ecosystem. Main threat from large scale biofuels utilization comes from deforestation of land that is needed for cultivation of crops. Every year large areas of rainforests in South East Asia and South America are irretrievably lost due to increasing demand. Combustion of wood and oxidation of peat during drying emits enormous quantities of CO2 into the atmosphere which is contrary to biodiesel appellation as "CO2 balanced fuel". Unlike conventional crops that are used for production of biodiesel (rapeseed, soybean, palm etc.), possible production from algae would significantly lower unit of land needed for biofuel production. Contemporary researches give some estimation of about 25 times greater yield than palm plantation and 100 times over rapeseed, which is common biodiesel production crop in EU. Regarding lately high world oil prices, greater investment in researches upon algae, as a new source of biofuel, are bringing technological solutions for economically production start-up.
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  430. Algal biodiesel economy and competition among bio-fuels
    Abstract

    Lee, D. H. 2011. Algal biodiesel economy and competition among bio-fuels. Bioresource Technology. 102(1) 43-49

    This investigation examines the possible results of policy support in developed and developing economies for developing algal biodiesel through to 2040. This investigation adopts the Taiwan General Equilibrium Model-Energy for Bio-fuels (TAIGEM-EB) to predict competition among the development of algal biodiesel, bioethanol and conventional crop-based biodiesel. Analytical results show that algal biodiesel will not be the major energy source in 2040 without strong support in developed economies. In contrast, bioethanol enjoys a development advantage relative to both forms of biodiesel. Finally, algal biodiesel will almost completely replace conventional biodiesel. CO(2) reduction benefits the development of the bio-fuels industry. (C) 2010 Elsevier Ltd. All rights reserved.
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  431. Algal Biomass and Biodiesel Production
    Abstract

    Shalaby, E. A. 2011. Algal Biomass and Biodiesel Production. Biodiesel - Feedstocks and Processing Technologies. 111-132

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  432. Anaerobic digestion of microalgae residues resulting from the biodiesel production process
    Abstract

    Ehimen, E. A.; Sun, Z. F.; Carrington, C. G.; Birch, E. J.; Eaton-Rye, J. J. 2011. Anaerobic digestion of microalgae residues resulting from the biodiesel production process. Applied Energy. 88(10) 3454-3463

    The recovery of methane from post transesterified microalgae residues has the potential to improve the renewability of the microalgae biomass to biodiesel' conversion process as well as reduce its cost and environmental impact. This paper deals with the anaerobic digestion of microalgae biomass residues (post transesterification) using semi-continuously fed reactors. The influence of substrate loading concentrations and hydraulic retention nines on the specific methane yield of the anaerobically digested microalgae residues was investigated. The co-digestion of the microalgae residues with glycerol as well as the influence of temperature was also examined. It was found that the hydraulic retention period was the most significant variable affecting methane production from the residues, with periods (>5 days) corresponding to higher energy recovery. The methane yield was also improved by a reduction in the substrate loading rates, with an optimum substrate carbon to nitrogen ratio of 12.44 seen to be required for the digestion process. (C) 2010 Elsevier Ltd. All rights reserved.
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  433. Biodiesel from microalgae oil production in two sequential esterification/transesterification reactors: Pinch analysis of heat integration
    Abstract

    Sanchez, E.; Ojeda, K.; El-Halwagi, M.; Kafarov, V. 2011. Biodiesel from microalgae oil production in two sequential esterification/transesterification reactors: Pinch analysis of heat integration. Chemical Engineering Journal. 176211-216

    New sources of biomass for biofuels production had been studied in recent years. Microalgae as oil donors for biodiesel production are a very attractive alternative due to their several benefits but it still is a process that must overcome several technological barriers. Oil composition and the amount of free fatty acid (FFA) makes the microalgae oil a difficult yet promising alternative. In this paper, sequential stages of esterification and then transesterification were studied to convert the microalgae oil (MAO) in biodiesel, glycerol, and water mostly. A more realistic microalgae oil composition was simulated using 9 triglycerides (TG) and 9 FFA's in contrast with other studies were 1-5 components are used to represent the oil. A sensitivity analysis was performed to determine the temperature effect on the glycerol and water concentration. Finally, energy integration alternatives were analyzed to find a cost-effective way to produce biodiesel from MAO. (C) 2011 Elsevier B.V. All rights reserved.
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  434. Biodiesel production by simultaneous extraction and conversion of total lipids from microalgae, cyanobacteria, and wild mixed-cultures
    Abstract

    Wahlen, B. D.; Willis, R. M.; Seefeldt, L. C. 2011. Biodiesel production by simultaneous extraction and conversion of total lipids from microalgae, cyanobacteria, and wild mixed-cultures. Bioresource Technology. 102(3) 2724-2730

    Microalgae have been identified as a potential biodiesel feedstock due to their high lipid productivity and potential for cultivation on marginal land. One of the challenges in utilizing microalgae to make biodiesel is the complexities of extracting the lipids using organic solvents followed by transesterification of the extracts to biodiesel. In the present work, reaction conditions were optimized that allow a single step extraction and conversion to biodiesel in high yield from microalgae. From the optimized conditions, it is demonstrated that quantitative conversion of triglycerides from several different microalgae and cyanobacteria could be achieved, including from mixed microbial biomass collected from a municipal wastewater lagoon. Evidence is presented that for some samples, significantly more biodiesel can be produced than would be expected from available triglycerides, indicating conversion of fatty acids contained in other molecules (e.g., phospholipids) using this approach. The effectiveness of the approach on wet algae is also reported. (C) 2010 Elsevier Ltd. All rights reserved.
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  435. Biodiesel production from genetically engineered microalgae: Future of bioenergy in Iran
    Abstract

    Tabatabaei, M.; Tohidfar, M.; Jouzani, G. S.; Safarnejad, M.; Pazouki, M. 2011. Biodiesel production from genetically engineered microalgae: Future of bioenergy in Iran. Renewable & Sustainable Energy Reviews. 15(4) 1918-1927

    Current biomass sources for energy production in Iran include sewerage as well as agricultural, animal. food industry and municipal solid wastes, and are anticipated to account for about 14% of national energy consumption in near future. However, due to the considerable progress made in genetic engineering of various plants in Iran during the last decade and the great potentials of microalgae for biofuel production, these photosynthetic organisms could be nominated as the future source of bioenergy in Iran. An overview of status of bioenergy in the world and Iran as well as the potential and utilization of biomass in Iran is presented. The possibilities of increasing biofuel production through microalgal genetic engineering and the progress made so far are discussed. Biodiesel in the Iran and its future prospective is also reviewed, emphasizing the promising role of microalgae. (C) 2010 Elsevier Ltd. All rights reserved.
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  436. Biodiesel production with microalgae as feedstock: from strains to biodiesel