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Algae as biodiesel feedstock

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  1. 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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  2. 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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  3. 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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  4. 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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  5. 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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  6. 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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  7. 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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  8. Screening of marine microalgae isolated from the hypersaline Bardawil lagoon for biodiesel feedstock
    Abstract

    Abomohra, A.; El-Sheekh, M.; Hanelt, D. 2017. Screening of marine microalgae isolated from the hypersaline Bardawil lagoon for biodiesel feedstock. Renewable Energy. 1011266-1272

    Recently, microalgae have been attracting a wide attention as a source of high-lipid feedstock to produce biodiesel. A total of twenty one halophilic microalgae were isolated from the hypersaline Bardawil lagoon North Sinai, Egypt. Nine of them were further characterized with respect to biomass and fatty acid productivities. Biomass productivity as cellular dry weight (CDW), fatty acid content and, consequently, fatty acid productivity of the chlorophyte Tetraselmis elliptica was the highest among alltested strains (0.122 g CDW L-1 d(-1), 7736 mg g(-1) CDW and 14.1 mg L-1 d(-1), respectively). Lipid fractionation showed that total lipids represented 12.96 mg g(-1) CDW and neutral lipids represented 37% of the total lipids with corresponding iodine value of 70.3 g I-2/100 g oil. In all fractions, C16:0 and C18:1n-9 were predominant, being as high as 31 and 20% of total fatty acids in neutral lipids, 26 and 24% of total fatty acids in polar lipids and 28 and 26% of total fatty acids in phospholipids, respectively. This study demonstrates that the halophilic microalga T. elliptica isolated from hypersaline water is a promising species for biodiesel feedstock. (C) 2016 Elsevier Ltd. All rights reserved.
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  9. 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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  10. 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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  11. 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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  12. 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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  13. 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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  14. 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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  15. 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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  16. One-pot synthesis and recovery of fatty acid methyl esters (FAMEs) from microalgae biomass
    Abstract

    Nelson, D. R.; Viamajala, S. 2016. One-pot synthesis and recovery of fatty acid methyl esters (FAMEs) from microalgae biomass. Catalysis Today. 26929-39

    We report a scalable method for recovery of cellular lipids and subsequent conversion to products. When in situ transesterification was performed at high solid loadings (>20%( w/w)) by reacting microalgal biomass in acidified methanol (containing 5%(v/v) H2SO4), the released FAMEs were produced at sufficiently high concentrations such that their solubility limit in the reaction medium was exceeded. As a result, the FAMEs spontaneously formed a separate phase lighter than methanol that could be directly recovered without solvent extraction. Further, FAME production rates were easily predicted, even in concentrated biomass slurries, by models derived from fundamental reaction kinetics. Our results also suggest that un-reacted methanol and catalyst, when recovered, could be reused in subsequent reactions. Thus, this "one-pot" process represents a viable method for production of biodiesel from algal biomass since this approach (1) eliminates costs associated with co-solvent (e.g., hexane) use, recovery and storage, (2) is easily scalable by virtue of the reaction not being constrained by mass transport limitations, and (3) facilitates processing of concentrated biomass slurries that would reduce reactor volumes and minimize reactor and handling costs. (C) 2016 Z. Published by Elsevier B.V.
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  17. Performance evaluation of microalgae for concomitant wastewater bioremediation, CO2 biofixation and lipid biosynthesis for biodiesel application
    Abstract

    Nayak, M.; Karemore, A.; Sen, R. 2016. Performance evaluation of microalgae for concomitant wastewater bioremediation, CO2 biofixation and lipid biosynthesis for biodiesel application. Algal Research-Biomass Biofuels and Bioproducts. 16216-223

    This study was directed towards evaluating the potential of microalgae for simultaneous wastewater treatment, CO2 biofixation and lipid biosynthesis for biofuel application. The cultivation potential of various microalgal species in domestic wastewater (DWW) was studied in shake-flasks. The microalga, Scenedesmus sp. showed superior results in terms of the maximum specific growth rate of 0.44 d(-1), biomass yield of 0.43 g L-1, biomass productivity of 61.4 mg L-1 d(-1) and total lipid content of 23.1%. Subsequently, the performance evaluation of Scenedesmus sp. with respect to biomass growth, lipid accumulation, CO2 biofixation rate and nutrient uptake was carried out at different CO2 concentrations in a photobioreactor. The culture supplemented with 2.5% (v/v) CO2 was found most suitable and resulted in highest biomass productivity, total lipid content, lipid productivity, and CO2 consumption rate of 196 mg L-1 d(-1), 33.3%, 65.17 mg L-1 d(-1) and 368 mg L-1 d(-1), respectively. The microalga could bioremediate ammonium, nitrate, phosphate and chemical oxygen demand (COD) efficiently from the wastewater to the extent of 70-98%. The FAME composition of the microalgal lipid was found encouraging for biodiesel application as saturated: unsaturated fatty acid ratio was favorable to about 1.2:1. The study indicates that Scenedesmus sp. can efficiently utilize DWW for its growth instead of using synthetic culture medium and can produce a significant amount of biomass at 2.5% CO2 for biofuel application. (C) 2016 Elsevier B.V. All rights reserved.
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  18. Polar Lipid Composition of Biodiesel Algae Candidates Nannochloropsis oculata and Haematococcus pluvialis from Nano Liquid Chromatography Coupled with Negative Electrospray Ionization 14.5 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
    Abstract

    Liu, P. L.; Corilo, Y. E.; Marshall, A. G. 2016. Polar Lipid Composition of Biodiesel Algae Candidates Nannochloropsis oculata and Haematococcus pluvialis from Nano Liquid Chromatography Coupled with Negative Electrospray Ionization 14.5 T Fourier Transform Ion Cyclotron Resonance Mass Spectrometry. Energy & Fuels. 30(10) 8270-8276

    Algae lipids contain long-chain saturated and polyunsaturated fatty acids. The lipids may be transesterified to generate biodiesel fuel. Here, we compare polar lipid compositions for two microalgae, Nannochloropsis oculata and Haematococcus pluvialis, that are prospective lipid-rich feedstock candidates for an emerging biodiesel industry. Online nano liquid chromatography coupled with negative electrospray ionization 14.5 T Fourier transform ion cyclotron resonance mass spectrometry (()ESI FT-ICR MS) with newly modified ion optics provides ultrahigh mass accuracy and resolving power to identify hundreds of unique elemental compositions. Assignments are confirmed by isotopic fine structure for a polar lipid extract. Collision-induced-dissociation (CID) MS/MS provides additional structural information. H. pluvialis exhibits more highly polyunsaturated lipids than does N. oculata.
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  19. 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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  20. 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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  21. 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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  22. 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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  23. Particle emissions from microalgae biodiesel combustion and their relative oxidative potential
    Abstract

    Rahman, M. M.; Stevanovic, S.; Islam, M. A.; Heimann, K.; Nabi, M. N.; Thomas, G.; Feng, B.; Brown, R. J.; Ristovski, Z. D. 2015. Particle emissions from microalgae biodiesel combustion and their relative oxidative potential. Environmental Science-Processes & Impacts. 17(9) 1601-1610

    Microalgae are considered to be one of the most viable biodiesel feedstocks for the future due to their potential for providing economical, sustainable and cleaner alternatives to petroleum diesel. This study investigated the particle emissions from a commercially cultured microalgae and higher plant biodiesels at different blending ratios. With a high amount of long carbon chain lengths fatty acid methyl esters (C20 to C22), the microalgal biodiesel used had a vastly different average carbon chain length and level of unsaturation to conventional biodiesel, which significantly influenced particle emissions. Smaller blend percentages showed a larger reduction in particle emission than blend percentages of over 20%. This was due to the formation of a significant nucleation mode for the higher blends. In addition measurements of reactive oxygen species (ROS), showed that the oxidative potential of particles emitted from the microalgal biodiesel combustion were lower than that of regular diesel. Biodiesel oxygen content was less effective in suppressing particle emissions for biodiesels containing a high amount of polyunsaturated C20-C22 fatty acid methyl esters and generated significantly increased nucleation mode particle emissions. The observed increase in nucleation mode particle emission is postulated to be caused by very low volatility, high boiling point and high density, viscosity and surface tension of the microalgal biodiesel tested here. Therefore, in order to achieve similar PM (particulate matter) emission benefits for microalgal biodiesel likewise to conventional biodiesel, fatty acid methyl esters (FAMEs) with high amounts of polyunsaturated long-chain fatty acids (>= C20) may not be desirable in microalgal biodiesel composition.
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  24. Strategic planning design of microalgae biomass-to-biodiesel supply chain network: Multi-period deterministic model
    Abstract

    Ahn, Y. C.; Lee, I. B.; Lee, K. H.; Han, J. H. 2015. Strategic planning design of microalgae biomass-to-biodiesel supply chain network: Multi-period deterministic model. Applied Energy. 154528-542

    Many studies have developed mathematical programming models for optimal design of supply chains for agricultural or lingocellulosic biomass-derived bioethanol production. However, because of the shortcomings of using agricultural (food supply problems) and lingo-cellulosic biomass (low biomass availability and processing yield) as feedstock, use of micro-algal biomass has been considered for use as a feedstock for biodiesel (biofuel). Thus, in this study we developed a deterministic mathematical programming model for strategic planning design of a microalgae biomass-to-biodiesel supply chain network (MBBSCN) from feedstock fields to end users that simultaneously satisfies resource constraints, demand constraints, and technology over a long-term planning horizon.
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  25. 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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  26. A model for utilizing industrial off-gas to support microalgae cultivation for biodiesel in cold climates
    Abstract

    Laamanen, C. A.; Shang, H. L.; Ross, G. M.; Scott, J. A. 2014. A model for utilizing industrial off-gas to support microalgae cultivation for biodiesel in cold climates. Energy Conversion and Management. 88476-483

    Lipids produced by microalgae are a promising biofuel feedstock. However, as most commercial mass production of microalgae is in open raceway ponds it is generally considered only a practical option in regions where year-round ambient temperatures remain above 15 degrees C. To address this issue it has been proposed to couple microalgae production with industries that produce large amounts of waste heat and carbon dioxide (CO2). The CO2 would provide a carbon source for the microalgae and the waste heat would allow year-round cultivation to be extended to regions that experience seasonal ambient temperatures well below 15 degrees C. To demonstrate this concept, a dynamic model has been constructed that predicts the impact on algal pond temperature from both bubbled-in off-gas and heat indirectly recovered from off-gas. Simulations were carried out for a variety of global locations using the quantity off-gas and waste energy from a smelter's operations to determine the volume of microalgae that could be maintained above 15 degrees C. The results demonstrate the feasibility of year-round microalgae production in climates with relatively cold winter seasons. (C) 2014 Elsevier Ltd. All rights reserved.
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  27. 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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  28. Microalgae Versus Land Crops as Feedstock for Biodiesel: Productivity, Quality, and Standard Compliance
    Abstract

    Nascimento, I. A.; Marques, S. S. I.; Cabanelas, I. T. D.; de Carvalho, G. C.; Nascimento, M. A.; de Souza, C. O.; Druzian, J. I.; Hussain, J.; Liao, W. 2014. Microalgae Versus Land Crops as Feedstock for Biodiesel: Productivity, Quality, and Standard Compliance. Bioenergy Research. 7(3) 1002-1013

    Despite certain environmental advantages over fossil diesel, land crop-derived biodiesels may not satisfy the increasing worldwide demand for transportation fuels. As an abundant photosynthesizer, algae could be an adequate surrogate for biodiesel production. Nevertheless, high production costs, scarce selected species, and inaccurate assumptions about production yields represent industrial uncertainties. In this study, a reliable approach to analyzing algal biodiesel production has been developed based on species-to-species variations in oil productivity and quality. This approach compares biodiesels from Chlorophyta strains with land crop feedstock according to (i) potential yields, (ii) oil quality, and (iii) compliance with biodiesel quality standards. Algal yields were assessed by (i) extrapolating the strain-specific laboratory results to commercial-scale growth systems; (ii) converting volumetric to areal biomass productivity; and (iii) estimating oil yields for each strain, as the product of their projected areal biomass productivity for each growth system, and the oil percentage in biomass as determined in the laboratory. Biodiesel fuel properties were estimated by using fatty acid methyl ester profile predictive models. The Chlorophyta strains in this study provided annual oil yields that were generally higher than those of land crops by one order of magnitude. Six strains yielding more than 40 mg oil l(-1) day(-1) were identified as adequate for sustaining biodiesel production. Trebouxiophyceae algae were the most productive. Critical biodiesel parameters from both feedstock types suggest that most microalgae-derived biodiesels meet international fuel quality standards with better values than those of land crops. Because some of the highly productive feedstock does not simultaneously meet all the standards for a high quality biodiesel, optimization solutions are discussed.
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  29. Performance and emission characteristics of diesel fuel containing microalgae oil methyl esters
    Abstract

    Makareviciene, V.; Lebedevas, S.; Rapalis, P.; Gumbyte, M.; Skorupskaite, V.; Aglinskis, J. Z. 2014. Performance and emission characteristics of diesel fuel containing microalgae oil methyl esters. Fuel. 120233-239

    This report includes assessments of comparative studies on the physical, chemical, and motor properties of diesel fuels containing 30% (vol.) algae oil methyl esters (AME).
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  30. 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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  31. 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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  32. Screening of Microalgae for Biodiesel Feedstock
    Abstract

    Chen, Xi; He, Guoqiang; Deng, Zhiping; Wang, Nan; Jiang, Wei; Chen, Sanfeng 2014. Screening of Microalgae for Biodiesel Feedstock. Advances in Microbiology. Vol.04No.0712

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  33. 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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  34. 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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  35. Towards a sustainable approach for development of biodiesel from plant and microalgae
    Abstract

    Singh, B.; Guldhe, A.; Rawat, I.; Bux, F. 2014. Towards a sustainable approach for development of biodiesel from plant and microalgae. Renewable & Sustainable Energy Reviews. 29216-245

    The production of biodiesel can be accomplished using a variety of feedstock sources. Plant and microalgae based feedstocks are prominent and are studied extensively. Plant based feedstocks cultivated as monoculture on wastelands and trees in forests can cater towards partial fulfillment of feedstock requirements for biodiesel industry. Synthesis of biodiesel from microalgal oil has gathered immense interest and has potential to cater to the increasing feedstocks demands of the biodiesel industry. The major advantage offered by microalgal oil, as compared to plant based oils, is its potential for culture on non-arable land. Despite of the advantages of microalgal oil as a feedstock for biodiesel, there are constraints that have to be overcome in order to make it economical and sustainable. Sustainable approaches for both the plant and microalgae as feedstocks have been drawn. Despite there being several plant species, few have been found to be desirable as feedstocks for biodiesel production based on their lipid profiles. Among the microalgae, there are thousands of species and several of these have been cultured for extracting the oil to explore their feasibility in utilization as biodiesel feedstocks. Though, several of the microalgal species have shown potential for high biomass growth and lipid productivity, only a few have been found to provide a high biodiesel yield and conversion. Due to the several steps involved in the extraction of oil which are energy intensive, the cost of biodiesel from microalgal oil is high as compared with that obtained from the plant oils. A sustainable approach for utilizing plant and microalgal oils as feedstocks for biodiesel have been discussed. The emerging cost effective methods in production of biodiesel have been described. The energy return and greenhouse gas emissions from biodiesel have been outlined. Together, the plant oil and microalgal oil can offer potential source of feedstocks for the production of biodiesel. (C) 2013 Elsevier Ltd. All rights reserved.
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  36. 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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  37. An overview of palm, jatropha and algae as a potential biodiesel feedstock in Malaysia
    Abstract

    Yunus, S.; Abdullah, N. R.; Mamat, R.; Rashid, A. A. 2013. An overview of palm, jatropha and algae as a potential biodiesel feedstock in Malaysia. 2nd International Conference on Mechanical Engineering Research (Icmer 2013). 50

    The high demand to replace petroleum fuel makes renewable and sustainable sources such as Palm oil, Jatropha oil and Algae a main focus feedstock for biodiesel production in Malaysia. There are many studies conducted on Palm oil and Jatropha oil, however, the use of Algae as an alternative fuel is still in its infancy. Malaysia already implemented B5 based Palm oil as a feedstock and this biodiesel has been proven safe and can be used without any engine modification. The use of biodiesel produced from these feedstock will also developed domestic economic and provide job opportunities especially in the rural area. In addition, biodiesel has many advantages especially when dealing with the emissions produce as compared to petroleum fuel such as; it can reduce unwanted gases and particulate matter harmful to the atmosphere and mankind. Thus, this paper gathered and examines the most prominent engine emission produced from Palm oil and Jatropha feedstock and also to observe the potential of Algae to be one of the sources of alternative fuel in Malaysia.
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  38. 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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  39. Microalgae-based biodiesel: Economic analysis of downstream process realistic scenarios
    Abstract

    Rios, S. D.; Torres, C. M.; Torras, C.; Salvado, J.; Mateo-Sanz, J. M.; Jimenez, L. 2013. Microalgae-based biodiesel: Economic analysis of downstream process realistic scenarios. Bioresource Technology. 136617-625

    Microalgae oil has been identified as a reliable resource for biodiesel production due to its high lipid productivity and potential cultivation in non-fertile locations. However, high scale production of microalgae based biodiesel depends on the optimization of the entire process to be economically feasible. The selected strain, medium, harvesting methods, etc., sorely affects the ash content in the dry biomass which have a direct effect in the lipid content. Moreover, the suitable lipids for biodiesel production, some of the neutral/saponifiable, are only a fraction of the total ones (around 30% dry base biomass in the best case). The present work uses computational tools for the modeling of different scenarios of the harvesting, oil extraction and transesterification. This rigorous modeling approach detects process bottlenecks that could have led to an overestimation of the potentiality of the microalgae lipids as a resource for the biodiesel production. (C) 2013 Elsevier Ltd. All rights reserved.
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  40. Microwave assisted lipid extraction from microalgae using biodiesel as co-solvent
    Abstract

    Iqbal, J.; Theegala, C. 2013. Microwave assisted lipid extraction from microalgae using biodiesel as co-solvent. Algal Research-Biomass Biofuels and Bioproducts. 2(1) 34-42

    This study reports the solvent potential of biodiesel (methyl soyate) for microalgal lipid extraction while employing microwave-assisted extraction (MAE). Two co-solvent systems, BD20 and BD40 containing 20% and 40% of biodiesel in ethanol respectively, were experimented at 80 degrees C, 100 degrees C, and 120 degrees C in MAE. Results were compared to those of the MAE using chloroform and ethanol (1:2) as well as conventional 8 h Soxhlet extraction. Results indicated that approximately 66% and 78% of the oil within the cells were extracted with BD40 at 80 degrees C and 100 degrees C, respectively. Increase in temperature to 120 degrees C increased the efficiency of 0D40 extraction to 115.5%, relative to conventional Soxhlet extraction. The BD20 co-solvent on the other hand extracted 27%, 34%, and 24% of oil at 80 degrees C, 100 degrees C, and 120 degrees C temperatures respectively. MAE using chloroform and ethanol showed 32%, 93%, and 108% of oil compared to Soxhlet Data indicated that increase in biodiesel proportion in the co-solvent and increased temperature lead to more efficient extraction. Scanning electron microscope (SEM) images were used to discern the cell structures before and after the extraction. This study was aimed at identifying benign alternatives for the traditional toxic solvents like n-hexane for extracting microalgal lipids. (c) 2012 Elsevier B.V. All rights reserved.
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  41. 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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  42. 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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  43. 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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  44. 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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  45. Oil Extraction and Fatty Acid Characterization of Nannochloropsis Oculata Microalgae for Biodiesel Applications
    Abstract

    Gog, A.; Senila, L.; Roman, M.; Luca, E.; Roman, C.; Irimie, F. D. 2012. Oil Extraction and Fatty Acid Characterization of Nannochloropsis Oculata Microalgae for Biodiesel Applications. Studia Universitatis Babes-Bolyai Chemia. 57(1) 111-118

    Microalgae, the third generation biodiesel feedstock, have emerged as one of the most promising alternative sources of lipids that can be used in the production of biodiesel due to their advantages over conventional crops. The aim of this study was to obtain Nannochloropsis oculata microalgae oil using hexane extraction methods together with fatty acid characterization for biodiesel application. The chemical composition of microalgae showed a high total lipid content, N. oculata microalgae being a potential feedstock for biodiesel production. For algal oil extraction, dynamic extraction with Soxhlet apparatus proved more efficient, with a lipid yield of 0.190 g/g dried microalgae comparatively to only 0.136 g lipid/g dried microalgae for static hexane extraction. The main fatty acids for N. oculata microalgae are palmitic acid, palmitoleic acid, eicosatrienoic acid and eicosapentaenoic acid, the latest being also the major constituent, with a value of 48.86% (w/w).
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  46. Oxidative Stability of Algae Derived Methyl Esters
    Abstract

    Bucy, H.; Marchese, A. J. 2012. Oxidative Stability of Algae Derived Methyl Esters. Journal of Engineering for Gas Turbines and Power-Transactions of the Asme. 134(9)

    Microalgae are currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gal/acre/year) in comparison to current terrestrial feedstocks. For algal methyl ester biodiesel, fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chain-polyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. Moreover, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value, thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability of algal methyl esters with varying levels of EPA and DHA. Tests were conducted using a Metrohm 743 Rancimat with automatic induction period determination following ASTM D6751 and EN 14214 standards, which call for induction periods of at least 3 and 6 h, respectively. Tests were conducted at a temperature of 110 degrees C and airflow of 10 l/h with model algal methyl ester compounds synthesized from various sources to match the fatty acid compositions of several algae strains subjected to varying removal amounts of roughly 0% to 100% LC-PUFA. In addition, tests were also conducted with real algal methyl esters produced from multiple sources. The bis-allylic position equivalent (BAPE) was calculated for each fuel sample to quantify the level of unsaturation. The induction period was then plotted as a function of BAPE, which showed that the oxidative stability varied exponentially with the amount of LC-PUFA. The results suggest that removal of 45% to 65% of the LC-PUFA from Nannochloropsis-based algal methyl esters would be sufficient for meeting existing ASTM specifications for oxidative stability. [DOI: 10.1115/1.4006712]
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  47. 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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  48. A technical evaluation of biodiesel from vegetable oils vs. algae. Will algae-derived biodiesel perform?
    Abstract

    Knothe, G. 2011. A technical evaluation of biodiesel from vegetable oils vs. algae. Will algae-derived biodiesel perform?. Green Chemistry. 13(11) 3048-3065

    Biodiesel, one of the most prominent renewable alternative fuels, can be derived from a variety of sources including vegetable oils, animal fats and used cooking oils, as well as alternative sources such as algae. While issues such as land-use change, food vs. fuel, feedstock availability, and production potential have influenced the search for the "best" feedstocks, an issue that will ultimately determine the usability of any biodiesel fuel is that of fuel properties. Issues such as cold flow and oxidative stability have been problematic for biodiesel. The fatty acid profile of a biodiesel fuel is largely identical to that of the feedstock and significantly influences these properties. This article compares biodiesel derived from vegetable oils and biodiesel obtained from algae in light of fuel properties. While the properties of biodiesel fuels derived from vegetable oils are well-known, the properties of biodiesel obtained from algal oils have usually not been reported. The fatty acid profiles of many algal oils possess high amounts of saturated and polyunsaturated fatty acids. Thus, biodiesel fuels derived from algae in many cases likely possess poor fuel properties, i.e., both poor cold flow and low oxidative stability simultaneously. This observation shows that production potential alone does not suffice to judge the suitability of a feedstock for biodiesel use. This article also summarizes how the fuel properties of biodiesel can be improved through modification of the fatty ester content. Algal oils for biodiesel production are probably best produced under tightly controlled conditions since the fatty acid profile of algal oils is very susceptible to changes in these conditions. Algal oils likely yielding biodiesel with the least problematic properties as determined by reported fatty acid profiles are discussed.
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  49. Microalgae as Feedstocks for Biodiesel Production
    Abstract

    Liu, J.; Huang, J. C.; Chen, F. 2011. Microalgae as Feedstocks for Biodiesel Production. Biodiesel - Feedstocks and Processing Technologies. 133-160

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  50. Microalgae biodiesel via in situ methanolysis
    Abstract

    Carvalho, R. M.; Vargas, J. V. C.; Ramos, L. P.; Marino, C. E. B.; Torres, J. C. L. 2011. Microalgae biodiesel via in situ methanolysis. Journal of Chemical Technology and Biotechnology. 86(11) 1418-1427

    BACKGROUND: Microalgae have recently been considered a potential feedstock for biodiesel production, since they do not compete with agricultural land, unlike oil crops. However, the production processes must be energetically and economically viable. Therefore, an in situ methanolysis process is proposed for biodiesel production directly from microalgae biomass, to avoid the need for the separation and extraction steps.
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  51. Net energy analysis of the production of biodiesel and biogas from the microalgae: Haematococcus pluvialis and Nannochloropsis
    Abstract

    Razon, L. F.; Tan, R. R. 2011. Net energy analysis of the production of biodiesel and biogas from the microalgae: Haematococcus pluvialis and Nannochloropsis. Applied Energy. 88(10) 3507-3514

    Microalgae have been proposed as possible alternative feedstocks for the production of biodiesel because of their high photosynthetic efficiency. The high energy input required for microalgal culture and oil extraction may negate this advantage, however. There is a need to determine whether microalgal biodiesel can deliver more energy than is required to produce it. In this work, net energy analysis was done on systems to produce biodiesel and biogas from two microalgae: Haematococcus pluvialis and Nannochloropsis. Even with very optimistic assumptions regarding the performance of processing units, the results show a large energy deficit for both systems, due mainly to the energy required to culture and dry the microalgae or to disrupt the cell. Some energy savings may be realized from eliminating the fertilizer by the use of wastewater or. in the case of H. pluvialis, recycling some of the algal biomass to eliminate the need for a photobioreactor, but these are insufficient to completely eliminate the deficit. Recommendations are made to develop wet extraction and transesterification technology to make microalgal biodiesel systems viable from an energy standpoint. (C) 2010 Elsevier Ltd. All rights reserved.
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  52. Oxidative Stability of Algae Derived Methyl Esters Containing Varying Levels of Methyl Eicosapentaenoate and Methyl Docosahexaenoate
    Abstract

    Bucy, H.; Marchese, A. J. 2011. Oxidative Stability of Algae Derived Methyl Esters Containing Varying Levels of Methyl Eicosapentaenoate and Methyl Docosahexaenoate. Proceedings of the Asme Internal Combustion Engine Division Fall Technical Conference (Icef). 121-134

    Microalgae is currently receiving strong consideration as a potential biofuel feedstock to help meet the advanced biofuels mandate of the 2007 Energy Independence and Security Act because of its theoretically high yield (gallons/acre/year) in comparison to current terrestrial feedstocks. Microalgae lipids can be converted into a variety of biofuels including fatty acid methyl esters (e.g. biodiesel), renewable diesel, renewable gasoline or synthetic paraffinic aviation kerosene. For algal methyl ester biodiesel, fuel properties will be directly related to the fatty acid composition of the lipids produced by the given microalgae strain. Several microalgae species under consideration for wide scale cultivation, such as Nannochloropsis, produce lipids with fatty acid compositions containing substantially higher quantities of long chain-polyunsaturated fatty acids (LC-PUFA) in comparison to terrestrial feedstocks. It is expected that increased levels of LC-PUFA will be problematic in terms of meeting all of the current ASTM specifications for biodiesel. For example, it is well known that oxidative stability decreases with increasing levels of LC-PUFA. However, these same LC-PUFA fatty acids, such as eicosapentaenoic acid (EPA: C20:5) and docosahexaenoic acid (DHA: C22:6) are known to have high nutritional value thereby making separation of these compounds economically attractive. Given the uncertainty in the future value of these LC-PUFA compounds and the economic viability of the separation process, the goal of this study was to examine the oxidative stability of algal methyl esters with varying levels of EPA and DHA. Tests were conducted using a Metrohm 743 Rancimat with automatic induction period determination following ASTM D6751 and EN 14214 standards, which call for induction periods of at least 3 hours and 6 hours, respectively. Tests were conducted at a temperature of 110 degrees C and airflow of 10 L/h with model algal methyl ester compounds synthesized from various sources to match the fatty acid compositions of several algae strains subjected to varying removal amounts of roughly 0 to 100 percent LC-PUFA. In addition, tests were also conducted with real algal methyl esters produced from multiple sources. The bis-allylic position equivalent (BAPE) was calculated for each fuel sample to quantify the level of unsaturation. The induction period was then plotted as a function of BAPE, which showed that the oxidative stability varied exponentially with the amount of LC-PUFA. The results suggest that removal of 45 to 65 percent of the LC-PUFA from Nannochloropsis-based algal methyl esters would be sufficient for meeting existing ASTM specifications for oxidative stability.
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  53. Potential of microalgae oil from Dunaliella tertiolecta as a feedstock for biodiesel
    Abstract

    Tang, H. Y.; Abunasser, N.; Garcia, M. E. D.; Chen, M.; Ng, K. Y. S.; Salley, S. O. 2011. Potential of microalgae oil from Dunaliella tertiolecta as a feedstock for biodiesel. Applied Energy. 88(10) 3324-3330

    Alternative, non-food based biomass fuel feedstock development is vital for our national security, economy and the environment. Microalgae are among the most promising of these alternatives. Microalgal cell growth rates and metabolic products are affected by a combination of environmental parameters. In this work, the influences of light source, light intensity, CO2 concentration, and photoperiod on the growth of Dunaliella tertiolecta (D. tertiolecta) were studied. The effects of these environmental parameters on the lipid content and fatty acid composition of D. tertiolecta were also investigated. Red light-emitting diodes (LEDs), white LEDs, and fluorescent lights were all found to be effective for algal growth. Increasing light intensity resulted in significantly more rapid algal growth, and increasing the period of light also significantly increased biomass productivity. Similar growth rates were observed for 2%, 4%, and 6% CO2-concentrations. The different light sources and intensities were found to have no significant effect on FAME composition of D. tertiolecto. Methyl linolenate and methyl palmitate were found to be the major components of FAME produced from D. tertiolecta oil. D. tertiolecta and its derived oils should be a suitable feedstock for biofuel production. (C) 2010 Elsevier Ltd. All rights reserved.
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  54. Prospects of Microalgae of North East India for Biodiesel Production
    Abstract

    Talukdar, J.; Kalita, M. C. 2011. Prospects of Microalgae of North East India for Biodiesel Production. Algae Biofuel. 69-90

    The triad of environmental, energy and economic security are the key issues for the sustainability of a real sense developmental process, which are now being seriously jeopardized with our impetuous activities. Various options of generating renewable energy alternatives are being explored due to the growing concern of diminishing fossil fuel reserves and their contributions towards the enrichment of air with major Greenhouse Gas CO2, which induce serious environmental consequences. An elevated level of CO2 in the atmosphere is chiefly responsible for the warming of global climate. Adoptions of effective mitigation strategies with clean energy development are therefore need of the hour for the sustainability of the developmental processes. Alternative fuel productions from renewable photosynthetic biological sources have the potential to provide an environment friendly sustainable energy system for the society besides mitigating CO2. The use of biomass for energy is largely motivated from the stand point of global energy crisis and global environmental issues. Alternative fuels that derived from biomass would reduce GHGs concentration potentially and could replace fossil fuels currently being used. Biodiesel is a clean burning renewable liquid biofuel, currently gaining worldwide acceptance as an able alternative to petroleum fuel. Biodiesel fuel production from microalgae has attracted much attention in recent times as a promising bio-feedstock for alternative liquid fuel production over other non-edible oil seed crops owing to their higher oil yielding efficiency, faster growth rate, higher CO2 fixation and wide range of tolerance to varying environmental conditions. Large scale cultivation of microalgae for liquid biofuel production with an integrated and innovative approach for feeding CO2 generated by industrial process using sewage/waste water might be an optimal solution to global warming, rising fuel crisis and saving our precious fresh water resources. The efficiency of microalgal liquid biofuel production largely depends on the selection of potent strains and appropriate technology. Exploration of the existing microalgal biodiversity has therefore a key role in finding an appropriate strain for sustainable production of biodiesel. India is facing formidable challenges in meeting its energy demands and in providing adequate energy of desired quality in various forms in a sustainable manner and at competitive prices. India produces only 22% of the mineral fuel requirement of a year and the rest is imported at a huge cost of foreign money. With the escalating crude oil prices in the international market and to ward off Global Warming that threatens our very existence, it is pertinent that India's need for biofuel development is the order of the day. India has vast expanse of waste and marginal land, tropical climate and vast manpower for developing sustainable biodiesel production towards its national energy security. The North Eastern region of India, more particularly Assam has an ambient of harboring rich diversity of freshwater microalgae. There was no earlier record regarding the oleaginous microalgae of the region. Accordingly a study was conducted and 22 microalgal species were isolated and screened for oil content. Among the isolated microalgae, Botryococcus braunii, Ankistrodesmus sp., Scenedesmus sp., Euglena sp., Navicula sp. and Nitzchia sp. are a few oleaginous microalgae noteworthy for biodiesel production.
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  55. Screening of marine microalgae for biodiesel feedstock
    Abstract

    Thi, T. Y. D.; Sivaloganathan, B.; Obbard, J. P. 2011. Screening of marine microalgae for biodiesel feedstock. Biomass & Bioenergy. 35(7) 2534-2544

    Biodiesel production from microalgae lipids is increasingly regarded as a more sustainable and feasible alternative to conventional biodiesel feedstocks derived from terrestrial bioenergy crops. A total of ninety-six strains of marine microalgae, with an elevated biomass productivity and intracellular lipid content, were isolated from the coastal waters of Singapore using an automated flow cytometric cell-sorting technique. Cell sorting was based on the two-dimensional distribution of algal cells for red fluorescence (representing chlorophyll auto-fluorescence) against forward-light scatter (representing cell size) and red vs. green fluorescence. Twenty-one of the strains were further characterized with respect to cell growth rate, biomass concentration, lipid content (total and neutral lipid) and fatty acid profile. The growth rates of Skeletonema costatum, Chaetoceros and Thalassiosira species were greatest among the entire strains, but in terms of absolute lipid yield Nannochloropsis strains predominated. Nannochloropsis strains had a lipid content ranging from 39.4% to 44.9% of dry weight biomass. Transesterification of the lipids yielded 25-51% of fatty acid methyl ester (FAME) i.e. biodiesel, where total FAME content ranged between 11 and 21% of dry weight biomass. This study describes the microalgae screening process and demonstrates that Nannochloropsis is a promising species for biodiesel feedstock. (C) 2011 Elsevier Ltd. All rights reserved.
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  56. Simultaneous saccharification of cassava starch and fermentation of algae for biodiesel production
    Abstract

    Lu, Y.; Ding, Y.; Wu, Q. Y. 2011. Simultaneous saccharification of cassava starch and fermentation of algae for biodiesel production. Journal of Applied Phycology. 23(1) 115-121

    A simpler approach to produce biodiesel from cassava starch was established, which successfully integrates the simultaneous saccharification and heterotrophic algal fermentation in an identical system. Batch experiments were investigated to verify the feasibility of raw starchy substrates fermentation for microalgal oil. The highest cell density (49.34 g L-1) and oil content (54.60%) were obtained in 5-L fed-batch cultivation via simultaneous saccharification and fermentation (SSF). It is demonstrated that the previous multistep hydrolysis and fermentation for feedstock oil could be replaced by SSF with higher energy efficiency and lower facility costs.
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  57. Sustainable production of biodiesel by microalgae and its application in agriculture
    Abstract

    Cenciani, K.; Bittencourt-Oliveira, M. C.; Feigl, B. J.; Cerri, C. C. 2011. Sustainable production of biodiesel by microalgae and its application in agriculture. African Journal of Microbiology Research. 5(26) 4638-4645

    According to estimates of the intergovernmental panel on climate change, the continued use of oil based-energy is responsible for more than two thirds of the anthropogenic emissions of greenhouse gases in the atmosphere. In Brazil, the National Program for use and biodiesel production has looked for the diversification of feedstock for biodiesel production. Among several alternative sources of energy, microalgae biomass shows great potential to be used as raw material for producing biodiesel. Rich in lipids and fatty acids, the oil yield per hectare in some strains of microalgae is considerably higher than the most conventional oilseed crops such as palm, Jatropha, soybean and sunflower. The commercial production triggered strong interest at the 1960s, with the development of a series of technologies to cultivate microalgae in open ponds and photobioreactors. Industrial or agricultural wastes such as vinasse previously treated in anaerobic digesters, for example, can be recycled and reused through the cultivation of microalgae, besides the application in the fertirrigation of sugar cane crop. This would also qualify the cultivation of microalgae as a clean development mechanism to reduce the levels of greenhouse gases.
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  58. Microalgae as feedstock for biodiesel production: Carbon dioxide sequestration, lipid production and biofuel quality
    Abstract

    Francisco, E. C.; Neves, D. B.; Jacob-Lopes, E.; Franco, T. T. 2010. Microalgae as feedstock for biodiesel production: Carbon dioxide sequestration, lipid production and biofuel quality. Journal of Chemical Technology and Biotechnology. 85(3) 395-403

    BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection.
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  59. MICROALGAE AS FEEDSTOCK FOR BIODIESEL PRODUCTION: Carbon dioxide sequestration, lipid production and biofuel quality
    Abstract

    Francisco, E. C.; Jacob-Lopes, E.; Neves, D. B.; Franco, T. T. 2010. MICROALGAE AS FEEDSTOCK FOR BIODIESEL PRODUCTION: Carbon dioxide sequestration, lipid production and biofuel quality. Biotechniques for Air Pollution Control. 115-115

    The objective of this paper was to evaluate the carbon dioxide sequestration capacity, biomass production, lipid content, lipid productivity and biodiesel quality of six microalgal strains cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity was the criteria for selection species; for the best specie, carbon dioxide sequestration rates, biomass productivity, lipid content and lipid productivity of 17.8 mg/L . min, 20.1 mg/L . h, 27.0% and 5.3 mg/L . h were obtained. Qualitative analysis of the fatty acid methyl esters demonstrates the predominance on saturated (43.5%) and monounsaturated (41.9%) fatty acids. The critical parameters for quality properties of biodiesel evaluated (ester content, 99.85%; cetane number, 56.73; iodine value, 65.00 gI(2)/100 g; degree of unsaturation, 74.07% and cold filter plugging point, 4.54 degrees C) comply with the US Standard (ASTM 6751), European Standard (EN 14214), Brazilian National Petroleum Agency (ANP 255) and Australian Standard for biodiesel. The novelty of this paper is the estimation of the fuel properties of the microalgal biodiesel and the comparative study of conventional sources used as feedstock for biodiesel manufacture, facilitating worldwide advances in this research area.
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  60. Microalgae for biodiesel production and other applications: A review
    Abstract

    Mata, T. M.; Martins, A. A.; Caetano, N. S. 2010. Microalgae for biodiesel production and other applications: A review. Renewable & Sustainable Energy Reviews. 14(1) 217-232

    Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration Of CO(2), wastewater treatment, in human health, as food additive, and for aquaculture. (C) 2009 Elsevier Ltd. All rights reserved.
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  61. Microalgae: A promising feedstock for biodiesel
    Abstract

    Deng, X. D.; Li, Y. J.; Fei, X. W. 2009. Microalgae: A promising feedstock for biodiesel. African Journal of Microbiology Research. 3(13) 1008-1014

    Biodiesel is a renewable and environmentally friendly energy source fuel produced through transesterification of plant oils or animal fats with short chain alcohols. The global market for biodiesel has been growing rapidly during the past few years, and it is poised for explosive growth in the next years. However, the lack of oil feedstocks limits the large-scale development of biodiesel to a large extent. Recently, microalgae have attracted increasing attention due to their many advantages for biodiesel production. Compared to traditional feedstocks such as rapeseed and soybean, microalgae can rapidly grow on nonagricultural land or in brackish water with high oil content and rapid growth rate. Moreover, they can absorb carbon dioxide as the carbon source for growth. Although many challenges remain in microalgal biodiesel production, more and more inventors committed to believe that the rewards would eventually outweigh the risks. To date, microalgae investments have reached over $900 million world wild. In this review paper, the related researches about microalgae as promising sources for biodiesel production were discussed.
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  62. Prospects of biodiesel production from microalgae in India
    Abstract

    Khan, S. A.; Rashmi; Hussain, M. Z.; Prasad, S.; Banerjee, U. C. 2009. Prospects of biodiesel production from microalgae in India. Renewable & Sustainable Energy Reviews. 13(9) 2361-2372

    Energy is essential and vital for development, and the global economy literally runs on energy. The use of fossil fuels as energy is now widely accepted as unsustainable due to depleting resources and also due to the accumulation of greenhouse gases in the environment. Renewable and carbon neutral biodiesel are necessary for environmental and economic sustainability. Biodiesel demand is constantly increasing as the reservoir of fossil fuel are depleting. Unfortunately biodiesel produced from oil crop, waste cooking oil and animal fats are not able to replace fossil fuel. The viability of the first generation biofuels production is however questionable because of the conflict with food supply. Production of biodiesel using microalgae biomass appears to be a viable alternative. The oil productivity of many microalgae exceeds the best producing oil crops. Microalgae are photosynthetic microorganisms which convert sunlight, water and CO(2) to sugars, from which macromolecules, such as lipids and triacylglycerols (TAGs) can be obtained. These TAGs are the promising and sustainable feedstock for biodiesel production. Microalgal biorefinery approach can be used to reduce the cost of making microalgal biodiesel. Microalgal-based carbon sequestration technologies cover the cost of carbon capture and sequestration. The present paper is an attempt to review the potential of microalgal biodiesel in comparison to the agricultural crops and its prospects in India. (C) 2009 Published by Elsevier Ltd.
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  63. Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production
    Abstract

    Schenk, P. M.; Thomas-Hall, S. R.; Stephens, E.; Marx, U. C.; Mussgnug, J. H.; Posten, C.; Kruse, O.; Hankamer, B. 2008. Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production. Bioenergy Research. 1(1) 20-43

    The use of fossil fuels is now widely accepted as unsustainable due to depleting resources and the accumulation of greenhouse gases in the environment that have already exceeded the "dangerously high" threshold of 450 ppm CO(2)-e. To achieve environmental and economic sustainability, fuel production processes are required that are not only renewable, but also capable of sequestering atmospheric CO(2). Currently, nearly all renewable energy sources (e.g. hydroelectric, solar, wind, tidal, geothermal) target the electricity market, while fuels make up a much larger share of the global energy demand (similar to 66%). Biofuels are therefore rapidly being developed. Second generation microalgal systems have the advantage that they can produce a wide range of feedstocks for the production of biodiesel, bioethanol, biomethane and biohydrogen. Biodiesel is currently produced from oil synthesized by conventional fuel crops that harvest the sun's energy and store it as chemical energy. This presents a route for renewable and carbon-neutral fuel production. However, current supplies from oil crops and animal fats account for only approximately 0.3% of the current demand for transport fuels. Increasing biofuel production on arable land could have severe consequences for global food supply. In contrast, producing biodiesel from algae is widely regarded as one of the most efficient ways of generating biofuels and also appears to represent the only current renewable source of oil that could meet the global demand for transport fuels. The main advantages of second generation microalgal systems are that they: (1) Have a higher photon conversion efficiency (as evidenced by increased biomass yields per hectare): (2) Can be harvested batch-wise nearly all-year-round, providing a reliable and continuous supply of oil: (3) Can utilize salt and waste water streams, thereby greatly reducing freshwater use: (4) Can couple CO(2)-neutral fuel production with CO(2) sequestration: (5) Produce non-toxic and highly biodegradable biofuels. Current limitations exist mainly in the harvesting process and in the supply of CO(2) for high efficiency production. This review provides a brief overview of second generation biodiesel production systems using microalgae.
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  64. Microalgae as feedstock for biodiesel production: carbon dioxide sequestration, lipid production and biofuel quality
    Abstract

    Francisco, E. C.; Jacob-Lopes, E.; Neves, D. B.; Franco, T. T. 2009. Microalgae as feedstock for biodiesel production: carbon dioxide sequestration, lipid production and biofuel quality. New Biotechnology. 25S278-S279

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  65. Microalgae as biodiesel & biomass feedstocks: Review & analysis of the biochemistry, energetics & economics
    Abstract

    Williams, P. J. L.; Laurens, L. M. L. 2010. Microalgae as biodiesel & biomass feedstocks: Review & analysis of the biochemistry, energetics & economics. Energy & Environmental Science. 3(5) 554-590

    Following scrutiny of present biofuels, algae are seriously considered as feedstocks for next-generation biofuels production. Their high productivity and the associated high lipid yields make them attractive options. In this review, we analyse a number aspects of large-scale lipid and overall algal biomass production from a biochemical and energetic standpoint. We illustrate that the maximum conversion efficiency of total solar energy into primary photosynthetic organic products falls in the region of 10%. Biomass biochemical composition further conditions this yield: 30 and 50% of the primary product mass is lost on producing cell protein and lipid. Obtained yields are one third to one tenth of the theoretical ones. Wasted energy from captured photons is a major loss term and a major challenge in maximising mass algal production. Using irradiance data and kinetic parameters derived from reported field studies, we produce a simple model of algal biomass production and its variation with latitude and lipid content. An economic analysis of algal biomass production considers a number of scenarios and the effect of changing individual parameters. Our main conclusions are that: (i) the biochemical composition of the biomass influences the economics, in particular, increased lipid content reduces other valuable compounds in the biomass; (ii) the "biofuel only'' option is unlikely to be economically viable; and (iii) among the hardest problems in assessing the economics are the cost of the CO(2) supply and uncertain nature of downstream processing. We conclude by considering the pressing research and development needs.
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  66. Microalgae as a sustainable energy source for biodiesel production: A review
    Abstract

    Ahmad, A. L.; Yasin, N. H. M.; Derek, C. J. C.; Lim, J. K. 2011. Microalgae as a sustainable energy source for biodiesel production: A review. Renewable & Sustainable Energy Reviews. 15(1) 584-593

    Of the three generations of biodiesel feedstocks described in this paper, food crops, non-food crops and microalgae-derived biodiesel, it was found that the third generation, microalgae, is the only source that can be sustainably developed in the future. Microalgae can be converted directly into energy, such as biodiesel, and therefore appear to be a promising source of renewable energy. This paper presents a comparison between the use of microalgae and palm oil as biodiesel feedstocks. It was found that microalgae are the more sustainable source of biodiesel in terms of food security and environmental impact compared to palm oil. The inefficiency and unsustainability of the use of food crops as a biodiesel source have increased interest in the development of microalgae species to be used as a renewable energy source. In this paper, the main advantages of using microalgae for biodiesel production are described in comparison with other available feedstocks, primarily palm oil. (C) 2010 Elsevier Ltd. All rights reserved.
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  67. Microalgae as a feedstock for biodiesel
    Abstract

    Demirbas, M. F. 2010. Microalgae as a feedstock for biodiesel. Energy Education Science and Technology Part a-Energy Science and Research. 25(1-2) 31-43

    Microalgae have long been recognized as potentially good Sources for biofuel production because of their high oil content and rapid biomass production. The oil productivity of many microalgae exceeds the best producing oil crops. In recent years, use of microalgae as an alternative biodiesel feedstock has gained renewed interest from researchers, entrepreneurs, and the general public. Biodiesel produced from microalgae is being investigated as an alternative. The lipid and fatty acid contents of microalgae vary in accordance with culture conditions. The average fatty acid contents of the algal oils are 36% oleic (18:1), 15% palmitic (16:0), 11% stearic (18:0), 8.4% iso-17:0, and 7.4% linoleic (18:2).
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  68. 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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  69. Mass culture of microalgae on wastewater and gases from sludge burning for production of biomass feedstock for biodiesel
    Abstract

    Kong, Q. X.; Chen, P.; Ruan, R. 2007. Mass culture of microalgae on wastewater and gases from sludge burning for production of biomass feedstock for biodiesel. Abstracts of Papers of the American Chemical Society. 234

    Sustainability is an essential aspect of biobased economy. The development of biofuels, an important component of biobased economy, must conform to sustainable behaviours. The work is centered on development of a new biofuel strategy, in which production of high oil content microalgae for biodiesel fuel is coupled with wastewater treatment and flue gas emission control, and thus provides significant environmental benefits and improves the economic feasibility. The work addresses the two priority areas defined "Development of new biofuel resources or technologies" and "Biofuels, the environment, and the economy", and will involve expertise in multiple areas including algae production, biology, waste treatment, water quality, engineering, biomass processing, and biofuel production. Management of wastewater and associated gaseous emission is very costly and technically challenging. With increasingly stringent regulations and limits on wastewater discharge and gaseous emission, modification of current conventional processes must be made to meet these new limits. These process modifications will require substantial capital investment and would also likely substantially increase operating costs. The present proposed project takes a creative approach in which microalgae is grown on nutrients supplied from wastewater and gaseous emission from wastewater treatment plants, harvested and extracted for oil that is converted to biodiesel fuel. This would create a win-win situation where water and air conditions are preserved while renewable energy is generated. Furthermore, savings/credits from the wastewater and emission treatments will significantly improve the economic feasibility of microalgal biodiesel.
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  70. Mass balance and life cycle assessment of biodiesel from microalgae incorporated with nutrient recycling options and technology uncertainties
    Abstract

    Yuan, J. H.; Kendall, A.; Zhang, Y. Z. 2015. Mass balance and life cycle assessment of biodiesel from microalgae incorporated with nutrient recycling options and technology uncertainties. Global Change Biology Bioenergy. 7(6) 1245-1259

    This article presents mass balances and a detailed life cycle assessment (LCA) for energy and greenhouse gases (GHGs) of a simulated microalgae biodiesel production system. Key parameters of the system include biomass productivity of 16 and 25gm(-2)day(-1) and lipid content of algae of 40% and 25% for low and normal nitrogen conditions respectively. Based on an oil extraction efficiency from wet biomass of 73.6% and methane yields from anaerobically digested lipid-extracted biomass of 0.31 to 0.34l per gram of volatile solids, the mass balance shows that recycling growth media and recovering nutrients from residual biomass through anaerobic digestion can reduce the total demand for nitrogen by 66% and phosphorus by 90%. Freshwater requirements can be reduced by 89% by recirculating growth media, and carbon requirements reduced by 40% by recycling CO2 from biogas combustion, for normal nitrogen conditions. A variety of technology options for each step of the production process and allocation methods for coproducts used outside the production system are evaluated using LCA. Extensive sensitivity and scenario analysis is also performed to provide better understanding of uncertainty associated with results. The best performing scenario consists of normal nitrogen cultivation conditions, bioflocculation and dissolved air flotation for harvesting, centrifugation for dewatering, wet extraction with hexane, transesterification for biodiesel production, and anaerobic digestion of biomass residual, which generates biogas used in a combined heat and power unit for energy recovery. This combination of technologies and operating conditions results in life cycle energy requirements and GHG emissions of 1.02 MJ and 71g CO2-equivalent per MJ of biodiesel, with cultivation and oil extraction dominating energy use and emissions. Thus, even under optimistic conditions, the near-term performance of this biofuel pathway does not achieve the significant reductions in life cycle GHG emissions hoped for from second-generation biofuel feedstocks.
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  71. 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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  72. 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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  73. Life-cycle impacts of soybean and algae biodiesel: Case study of US marine vessels
    Abstract

    Tsang, M.; Fox-Lent, C.; Wallace, S.; Welp, T.; Bates, M.; Linkov, I. 2015. Life-cycle impacts of soybean and algae biodiesel: Case study of US marine vessels. Biofuels Bioproducts & Biorefining-Biofpr. 9(5) 567-580

    The push to find alternatives to fossil fuels has driven research and consumption of biofuels. Recent actions in the United States have placed an emphasis on the use of renewable fuels for improved sustainability of government operations. In 2013, the United States Army Corps of Engineers (USACE) measured atmospheric emissions from two navigation vessels consuming three different fuel types and found that biofuels have the potential to lower atmospheric emissions. These fuels have widely different production processes, however, and a full life-cycle assessment is necessary to provide a complete picture of these biofuels. The goal of this study was to identify whether transitioning navigation vessels to operate on biodiesel would have the potential to lower human health and environmental impacts. This study focuses on the complete life cycle of these fuels in USACE marine vessels by employing a well-to-wheels life-cycle assessment comparing the impacts of a 100% soy-based biodiesel and an algal-based biodiesel blend to a conventional diesel. Overall, soybean-based biodiesel had lower impacts compared to algal-based biodiesel. Impacts from conventional diesel were generally lower than algal-based biodiesel, but impacts between conventional diesel and soybean-based biodiesel were mixed. While greenhouse gas emissions during the use phase were reduced for the biofuels (after considering only the non-biogenic fraction of carbon emission), a complete look at the life-cycle resulted in cases where emissions could be greater than conventional diesel. Biodiesel impacts depended greatly on modeling assumptions made in the life-cycle system boundaries and inventory such as allocation method and assumptions about feedstock growth and harvesting. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.
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  74. Life-cycle analysis on biodiesel production from microalgae: Water footprint and nutrients balance
    Abstract

    Yang, J.; Xu, M.; Zhang, X. Z.; Hu, Q. A.; Sommerfeld, M.; Chen, Y. S. 2011. Life-cycle analysis on biodiesel production from microalgae: Water footprint and nutrients balance. Bioresource Technology. 102(1) 159-165

    This research examines the life-cycle water and nutrients usage of microalgae-based biodiesel production. The influence of water types, operation with and without recycling, algal species, geographic distributions are analyzed. The results confirm the competitiveness of microalgae-based biofuels and highlight the necessity of recycling harvested water and using sea/wastewater as water source. To generate 1 kg biodiesel, 3726 kg water, 0.33 kg nitrogen, and 0.71 kg phosphate are required if freshwater used without recycling. Recycling harvest water reduces the water and nutrients usage by 84% and 55%. Using sea/wastewater decreases 90% water requirement and eliminates the need of all the nutrients except phosphate. The variation in microalgae species and geographic distribution are analyzed to reflect microalgae biofuel development in the US. The impacts of current federal and state renewable energy programs are also discussed to suggest suitable microalgae biofuel implementation pathways and identify potential bottlenecks. (C) 2010 Elsevier Ltd. All rights reserved.
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  75. Life cycle assessment of biodiesel from soybean, jatropha and microalgae in China conditions
    Abstract

    Hou, J.; Zhang, P. D.; Yuan, X. Z.; Zheng, Y. H. 2011. Life cycle assessment of biodiesel from soybean, jatropha and microalgae in China conditions. Renewable & Sustainable Energy Reviews. 15(9) 5081-5091

    Increasing demand for transport fuels has driven China to attach great importance to biodiesel development. To evaluate the environmental impacts caused by producing and driving with biodiesel made from soybean, jatropha, and microalgae under China conditions, the LCA methodology is used and the assessment results are compared with fossil diesel. The solar energy and CO(2) uptake in biomass agriculture and reduction of dependency on fossil fuels lead to a better performance on abiotic depletion potential (ADP), global warming potential (GWP), and ozone depletion potential (ODP) in the life cycle of biodiesel compared to fossil diesel. Except for ADP, GWP and ODP, producing and driving with biodiesel does not offer benefits in the other environmental impact categories including eutrophication, acidification, photochemical oxidation, and toxicity. Jatropha and microalgae are more competitive biodiesel feedstock compared to soybean in terms of all impacts. By using global normalization references and weighting method based on ecotaxes, the LCA single score for the assessed 10 mid-point impact categories of soybean, jatropha, and microalgae based biodiesel is 54, 37.2 and 3.67 times of that of fossil diesel, respectively. Improvement of biomass agriculture management, development of biodiesel production technologies, bettering energy structure and promoting energy efficiency in China are the key measures to lower environmental impacts in the life cycle of biodiesel in the future. Various sensitivity analyses have also been applied, which show that, choice of allocation method, transport distance, uncertainty in jatropha and microalgae yield and oil content, and recycling rate of harvest water of microalgae have significant influence on the life cycle environmental performance of biodiesel. (C) 2011 Elsevier Ltd. All rights reserved.
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  76. Life cycle analysis of algae biodiesel
    Abstract

    Sander, K.; Murthy, G. S. 2010. Life cycle analysis of algae biodiesel. International Journal of Life Cycle Assessment. 15(7) 704-714

    Algae biomass has great promise as a sustainable alternative to conventional transportation fuels. In this study, a well-to-pump life cycle assessment (LCA) was performed to investigate the overall sustainability and net energy balance of an algal biodiesel process. The goal of this LCA was to provide baseline information for the algae biodiesel process.
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  77. 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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  78. Isolation and screening of microalgae from natural habitats in the midwestern United States of America for biomass and biodiesel sources
    Abstract

    Lee, K.; Eisterhold, M. L.; Rindi, F.; Palanisami, S.; Nam, P. K. 2014. Isolation and screening of microalgae from natural habitats in the midwestern United States of America for biomass and biodiesel sources. J Nat Sci Biol Med. 5(2) 333-9

    Native species of microalgae were isolated from natural water bodies in the Midwestern United States of America and were screened for the ultimate goal of mass cultivation in Missouri and the surrounding states, and for their potential as biomass and biodiesel sources. A number of different nutrient media recipes were utilized to isolate the maximum number of colonies from each field samples. These nutrient recipes were modified in order to optimize the isolation and growth dynamics of specific colonies. All of the isolates were categorized based on the morphological appearance of the culture and the microscopic cellular appearance of the isolated colonies. Isolates included many common green microalgae and cyanobacteria. Lipid content was determined for selected strains that demonstrated relatively quick growth. Scenedesmus sp. that demonstrated the high growth rate, resistance to invasion, and contained sufficient amounts of lipid was investigated for its potential as a sustainable biomass and biodiesel feedstocks.
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  79. Isolation and screening of microalgae from agro-industrial wastewater (POME) for biomass and biodiesel sources
    Abstract

    Kamyab, H.; Din, M. F. M.; Ponraj, M.; Keyvanfar, A.; Rezania, S.; Taib, S. M.; Abd Majid, M. Z. 2016. Isolation and screening of microalgae from agro-industrial wastewater (POME) for biomass and biodiesel sources. Desalination and Water Treatment. 57(60) 29118-29125

    Indigenous microalgae (KR349061) were isolated from the agro-industrial wastewater and screened in order to determine their potential for biomass and biodiesel sources. Bold's Basal Medium was used to isolate the colonies from sample. The nutrient contents were altered in order to optimize the growth of the microalgae. The isolates were identified based on the morphology and microscopic appearance of the isolated colonies. It was seen that the isolates comprised of several common green microalgae and cyanobacteria, among which the ideal candidate was selected and further investigated. Lipid content was determined for the strains that showed rapid growth. The results showed that Chlamydomonas incerta achieved highest lipid content of biomass (42.6%) after 2d, also highest lipid productivity of 0.197mg/L/d was observed when the initial COD concentration was 500mg/L. C. incerta also showed higher growth rate and higher amount of lipid was examined for its potential as sustainable biodiesel feedstock along with its higher biomass yield.
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  80. 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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  81. Integration of algae cultivation as biodiesel production feedstock with municipal wastewater treatment: Strains screening and significance evaluation of environmental factors
    Abstract

    Li, Y. C.; Zhou, W. G.; Hu, B.; Min, M.; Chen, P.; Ruan, R. R. 2011. Integration of algae cultivation as biodiesel production feedstock with municipal wastewater treatment: Strains screening and significance evaluation of environmental factors. Bioresource Technology. 102(23) 10861-10867

    The objectives of this study are to find the robust strains for the centrate cultivation system and to evaluate the effect of environmental factors including light intensity, light-dark cycle, and exogenous CO(2) concentration on biomass accumulation, wastewater nutrient removal and biodiesel production. The results showed that all 14 algae strains from the genus of Chlorella, Haematococcus, Scenedesmus, Chlamydomonas, and Chloroccum were able to grow on centrate. The highest net biomass accumulation (2.01 g/L) was observed with Chlorella kessleri followed by Chlorella protothecoides (1.31 g/L), and both of them were proved to be capable of mixotrophic growth when cultivated on centrate. Environmental factors had significant effect on algal biomass accumulation, wastewater nutrients removal and biodiesel production. Higher light intensity and exogenous CO(2) concentration with longer lighting period promote biomass accumulation, biodiesel production, as well as the removal of chemical oxygen demand and nitrogen, while, lower exogenous CO(2) concentration promotes phosphorus removal. (C) 2011 Elsevier Ltd. All rights reserved.
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  82. Increased production of biodiesel feedstock in microalgae
    Abstract

    Tekinay, T.; Angun, P.; Ozkan, A. D.; Demiray, Y. E.; Cakmak, T. 2011. Increased production of biodiesel feedstock in microalgae. Current Opinion in Biotechnology. 22S49-S49

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  83. Improving the energy balance of microalgae biodiesel: Synergy with an autonomous sugarcane ethanol distillery
    Abstract

    Maranduba, H. L.; Robra, S.; Nascimento, I. A.; da Cruz, R. S.; Rodrigues, L. B.; Neto, J. A. D. 2016. Improving the energy balance of microalgae biodiesel: Synergy with an autonomous sugarcane ethanol distillery. Energy. 115888-895

    This study analyzed the algal biodiesel production system via dry-route, based on Chlorella vulgaris cultivated in raceways, by comparing the Net Energy Balance (NEB) and the Fossil Energy Ratio (FER) of five scenarios: CO (single system of biomass production); C1 (CO + pyrolysis of the microalgae press cake); C2 (CO + anaerobic co-digestion of the microalgae press cake); C3 and C4 (same conditions of Cl and C2, but integrating both scenarios into an autonomous ethanol distillery). Each scenario was analyzed under de perspective of energy allocation (a) and system expansion with avoided product (b). The results showed that with the energy allocation, only C3a and C4a improved the values of baseline scenario (COa) for NEB, in 120% and 72% respectively. When the system expansion is considered, none of the scenarios was better than the respective baseline scenario (Cob), in relation to the NEB. Considering the FER, C3a increased in 3.4% the values of COa, while C3b and C4b increased the values of COb in 54.1% and 28.8%, respectively. In general, system expansion showed the best scenarios: for the NEB COb showed the highest average values while C3b showed the highest average values for the FER. (C) 2016 Elsevier Ltd. All rights reserved.
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  84. High protein- and high lipid-producing microalgae from northern australia as potential feedstock for animal feed and biodiesel
    Abstract

    Duong, V. T.; Ahmed, F.; Thomas-Hall, S. R.; Quigley, S.; Nowak, E.; Schenk, P. M. 2015. High protein- and high lipid-producing microalgae from northern australia as potential feedstock for animal feed and biodiesel. Front Bioeng Biotechnol. 353

    Microalgal biomass can be used for biodiesel, feed, and food production. Collection and identification of local microalgal strains in the Northern Territory, Australia was conducted to identify strains with high protein and lipid contents as potential feedstock for animal feed and biodiesel production, respectively. A total of 36 strains were isolated from 13 samples collected from a variety of freshwater locations, such as dams, ponds, and streams and subsequently classified by 18S rDNA sequencing. All of the strains were green microalgae and predominantly belong to Chlorella sp., Scenedesmus sp., Desmodesmus sp., Chlamydomonas sp., Pseudomuriella sp., Tetraedron caudatum, Graesiella emersonii, and Mychonastes timauensis. Among the fastest growing strains, Scenedesmus sp. NT1d possessed the highest content of protein; reaching up to 33% of its dry weight. In terms of lipid production, Chlorella sp. NT8a and Scenedesmus dimorphus NT8e produced the highest triglyceride contents of 116.9 and 99.13 mug mL(-1) culture, respectively, as measured by gas chromatography-mass spectroscopy of fatty acid methyl esters. These strains may present suitable candidates for biodiesel production after further optimization of culturing conditions, while their protein-rich biomass could be used for animal feed.
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  85. 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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  86. 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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  87. Growing Algae for Biodiesel on Direct Sunlight or Sugars: A Comparative Life Cycle Assessment
    Abstract

    Orfield, N. D.; Levine, R. B.; Keoleian, G. A.; Miller, S. A.; Savage, P. E. 2015. Growing Algae for Biodiesel on Direct Sunlight or Sugars: A Comparative Life Cycle Assessment. Acs Sustainable Chemistry & Engineering. 3(3) 386-395

    Growing heterotrophic algae in reactors with sugar as the energy and carbon source rather than sunlight and carbon dioxide is an approach being commercialized today. However, the full environmental impacts of this fuel pathway have not been explored. The objective of this analysis was to compare the life cycle impacts of algal biodiesel produced heterotrophically to a phototrophic pathway featuring algae grown in ponds. A third, hybrid approach utilizing algae capable of both phototrophy and heterotrophy was also explored. Sugar beet and sugarcane were examined as feedstocks for the heterotrophic process. The results indicate that a reduction in the global warming potential (GWP) and an improvement in the net energy ratio (NER) for algal biodiesel could be possible for the heterotrophic and hybrid pathways relative to the phototroplaic, but only if reactor cultivation can be performed efficiently and with sugarcane as the feedstock For example, the NER varies from 0.6 to 1.6 for the heterotrophic pathway, depending on reactor performance, compared to 1.3 for the phototrophic pathway. Sugar crops used as feedstocks for heterotrophic cultivation present concerns about land constraints that are less of an issue for the phototrophic pathway. No pathway presented a clear advantage for the water stress impact metric.
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  88. A Framework to Report the Production of Biodiesel from Algae
    Abstract

    Beal, C. M.; Smith, C. H.; Webber, M. E.; Ruoff, R. S. 2009. A Framework to Report the Production of Biodiesel from Algae. Es2009: Proceedings of the Asme 3rd International Conference on Energy Sustainability, Vol 1. 105-115

    Recently, algae have received a significant amount of attention as a potential feedstock for alternative fuels. Although multiple fuels have been proposed that would use algae as a feedstock, the most commonly explored algae-based alternative fuel is biodiesel. There are several coarse estimates that quantify the potential of algae as a feedstock for biodiesel. Some of these analyses have not incorporated specific values of algal lipid content and did not include processing inefficiencies. For example, in some analyses, specificity to the algal species and growth conditions is not provided, thereby introducing the opportunity for error. In addition, all necessary processing steps required for biodiesel production and their associated energy, materials, and costs might not be included. The accuracy associated with these estimates can be improved by using data that are more specific, including all relevant information for biodiesel production, and by presenting information with more relevant metrics.
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  89. Feedstocks for Second-Generation Biodiesel: Microalgae's Biology and Oil Composition
    Abstract

    Leonardi, P. I.; Popovich, C. A.; Damiani, M. C. 2011. Feedstocks for Second-Generation Biodiesel: Microalgae's Biology and Oil Composition. Economic Effects of Biofuel Production. 317-346

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  90. 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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  91. Fatty-Acid Compositions of Three Strains of Blue-Green Algae Biomass, a Potential Feedstock for Producing Biodiesel Fuel
    Abstract

    Ten, L. N.; Kim, J. H.; Chae, S. M.; Yoo, S. A. 2015. Fatty-Acid Compositions of Three Strains of Blue-Green Algae Biomass, a Potential Feedstock for Producing Biodiesel Fuel. Chemistry of Natural Compounds. 51(4) 756-757

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  92. 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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  93. Evaluation of oil-producing algae as potential biodiesel feedstock
    Abstract

    Zhou, X. P.; Ge, H. M.; Xia, L.; Zhang, D. L.; Hu, C. X. 2013. Evaluation of oil-producing algae as potential biodiesel feedstock. Bioresource Technology. 13424-29

    This study attempted to connect the dots between laboratory research and the outdoors. Chlorella sp. NJ-18 was selected among seven oil-producing algae cultivated in this study because it had the highest lipid productivity. The nitrogen and phosphorus concentrations for cultivating this Chlorella strain were optimized indoors. This strain was incubated outdoors in a 70 L photobioreactor, containing the favorable nitrogen (8.32 mM urea) and phosphorus (0.18 mM monopotassium phosphate) concentrations. Semi-continuous cultivation was performed by harvesting 30 L biomass and replacing it with fresh medium. The maximum biomass and lipid productivity acquired outdoors were 91.84 and 24.05 mg L-1 d(-1), respectively. Furthermore, biomass productivity could be maintained at a high level throughout the cultivation process when using the semi-continuous mode, whereas it decreased dramatically in batch cultures. More than 95% of the total fatty acids obtained were C16 and C18, which are the main components for biofuel. (C) 2013 Elsevier Ltd. All rights reserved.
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  94. 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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  95. 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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  96. 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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  97. Engineering fatty acid biosynthesis in microalgae for sustainable biodiesel
    Abstract

    Blatti, J. L.; Michaud, J.; Burkart, M. D. 2013. Engineering fatty acid biosynthesis in microalgae for sustainable biodiesel. Current Opinion in Chemical Biology. 17(3) 496-505

    Microalgae are a promising feedstock for biodiesel and other liquid fuels due to their fast growth rate, high lipid yields, and ability to grow in a broad range of environments. However, many microalgae achieve maximal lipid yields only under stress conditions hindering growth and providing compositions not ideal for biofuel applications. Metabolic engineering of algal fatty acid biosynthesis promises to create strains capable of economically producing fungible and sustainable biofuels. The algal fatty acid biosynthetic pathway has been deduced by homology to bacterial and plant systems, and much of our understanding is gleaned from basic studies in these systems. However, successful engineering of lipid metabolism in algae will necessitate a thorough characterization of the algal fatty acid synthase (FAS) including protein-protein interactions and regulation. This review describes recent efforts to engineer fatty acid biosynthesis toward optimizing microalgae as a biodiesel feedstock.
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  98. 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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  99. Eco-Physiological Barriers and Technological Advances for Biodiesel Production from Microalgae
    Abstract

    Kaur, S.; Kalita, M. C.; Srivastava, R. B.; Spillane, C. 2011. Eco-Physiological Barriers and Technological Advances for Biodiesel Production from Microalgae. Biodiesel - Feedstocks and Processing Technologies. 161-176

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  100. Dynamic Microfiltration in Microalgae Harvesting for Biodiesel Production
    Abstract

    Rios, S. D.; Clavero, E.; Salvado, J.; Farriol, X.; Torras, C. 2011. Dynamic Microfiltration in Microalgae Harvesting for Biodiesel Production. Industrial & Engineering Chemistry Research. 50(4) 2455-2460

    Microalgae is a promising feedstock for biodiesel production because of its lipid content and because it helps to decrease the use of land for nonfood applications (second generation biomass for energy production). To produce biodiesel, several stages should be followed. An important one is microalgae concentration after the growth stage and prior to lipid extraction. Microfiltration is a possible method if its energy consumption is optimized, considering the total cost of the whole process and the value of the final product. Enhanced dynamic microfiltration has been tested as a method for reducing fouling and concentration polarization at low transmembrane pressure with promising results. Three variables have been considered so far: rotational speed, transmembrane pressure, and type of membrane (material and mean pore size).
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  101. 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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  102. Culture of Microalgae Chlorella minutissima for Biodiesel Feedstock Production
    Abstract

    Tang, H. Y.; Chen, M.; Garcia, M. E. D.; Abunasser, N.; Ng, K. Y. S.; Salley, S. O. 2011. Culture of Microalgae Chlorella minutissima for Biodiesel Feedstock Production. Biotechnology and Bioengineering. 108(10) 2280-2287

    Microalgae are among the most promising of non-food based biomass fuel feedstock alternatives. Algal biofuels production is challenged by limited oil content, growth rate, and economical cultivation. To develop the optimum cultivation conditions for increasing biofuels feedstock production, the effect of light source, light intensity, photoperiod, and nitrogen starvation on the growth rate, cell density, and lipid content of Chlorella minutissima were studied. The fatty acid content and composition of Chlorella minutissima were also investigated under the above conditions. Fluorescent lights were more effective than red or white light-emitting diodes for algal growth. Increasing light intensity resulted in more rapid algal growth, while increasing the period of light also significantly increased biomass productivity. Our results showed that the lipid and triacylglycerol content were increased under N starvation conditions. Thus, a two-phase strategy with an initial nutrient-sufficient reactor followed by a nutrient deprivation strategy could likely balance the desire for rapid and high biomass generation (124 mg/L) with a high oil content (50%) of Chlorella minutissima to maximize the total amount of oil produced for biodiesel production. Moreover, methyl palmitate (C16:0), methyl oleate (C18:1), methyl linoleate (C18: 2), and methyl linolenate (C18: 3) are the major components of Chlorella minutissima derived FAME, and choice of light source, intensity, and N starvation impacted the FAME composition of Chlorella minutissima. The optimized cultivation conditions resulted in higher growth rate, cell density, and oil content, making Chlorella minutissima a potentially suitable organism for biodiesel feedstock production. Biotechnol. Bioeng. 2011; 108: 2280-2287. (C) 2011 Wiley Periodicals, Inc.
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  103. 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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  104. Cultivation of algae in photobioreator and obtention of biodiesel
    Abstract

    Hobuss, C. B.; Rosales, P. F.; Venzke, D.; Souza, P. O.; Gobbi, P. C.; Gouvea, L. P.; Santos, M. A. Z.; Pinto, E.; Jacob-Lopes, E.; Pereira, C. M. P. 2011. Cultivation of algae in photobioreator and obtention of biodiesel. Revista Brasileira De Farmacognosia-Brazilian Journal of Pharmacognosy. 21(2) 361-364

    In this work we described the cultivation of Chlorella vulgaris in a photobioreactor to algal biomass production. The dried biomass was used as feedstock for biodiesel production, it presented 26% lipids and via sonocatalysis stage of the methodology resulted in 60% of fatty acid methyl esters (FAME). The FAME content was confirmed by Gas Chromatography (GC).
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  105. Cultivation of Algae in Photobioreactors for Biodiesel Production
    Abstract

    Pruvost, J. 2011. Cultivation of Algae in Photobioreactors for Biodiesel Production. Biofuels: Alternative Feedstocks and Conversion Processes. 439-464

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  106. A critical review on recent methods used for economically viable and eco-friendly development of microalgae as a potential feedstock for synthesis of biodiesel
    Abstract

    Sharma, Y. C.; Singh, B.; Korstad, J. 2011. A critical review on recent methods used for economically viable and eco-friendly development of microalgae as a potential feedstock for synthesis of biodiesel. Green Chemistry. 13(11) 2993-3006

    Microalgae are being considered as a viable feedstock for large- scale production of biodiesel. However, though it may look simpler to obtain lipids from microalgae, the overall process of choosing an algal strain, cultivation, harvesting, dewatering, and extraction of oil is quite complicated and not economically prudent at this time. A thorough understanding of algae and the overall biodiesel production process discussed in this paper is vital so that focused research might lower the costs involved. Various diverse species of microalgae are currently being used as feedstocks for biofuel. Heterotrophic culture may be preferred over photoautotrophic cultivation. For cultivation, specially fabricated photobioreactors (PBRs) have the capability to overcome the constraints and limitations of the open raceway ponds, although the former are cost intensive as compared to the latter. Exergy analysis of algal- biodiesel- carbon dioxide cycle shows the overall process to be renewable and hence should attain global attention.
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  107. Conversion of wastewater organics into biodiesel feedstock through the predator-prey interactions between phagotrophic microalgae and bacteria
    Abstract

    Li, C.; Ju, L. K. 2014. Conversion of wastewater organics into biodiesel feedstock through the predator-prey interactions between phagotrophic microalgae and bacteria. Rsc Advances. 4(83) 44026-44029

    We herein report a new route of cultivating phagotrophic microalgae with wastewater for biodiesel feedstock production. A continuous-flow process has been developed, through which organic matter of wastewater is first converted into the biomass of bacteria and then the bacteria are consumed by phagotrophic microalgae for growth and lipid production.
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  108. Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts - A model compound study
    Abstract

    Asikainen, M.; Munter, T.; Linnekoski, J. 2015. Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts - A model compound study. Bioresource Technology. 191300-305

    Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60-70 degrees C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step. (C) 2015 Elsevier Ltd. All rights reserved.
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  109. 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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  110. Comparison of harvesting methods for microalgae Chlorella sp. and its potential use as a biodiesel feedstock
    Abstract

    Ahmad, A. L.; Yasin, N. H. M.; Derek, C. J. C.; Lim, J. K. 2014. Comparison of harvesting methods for microalgae Chlorella sp. and its potential use as a biodiesel feedstock. Environmental Technology. 35(17) 2244-2253

    Three methods for harvesting Chlorella sp. biomass were analysed in this paper - centrifugation, membrane microfiltration and coagulation: there was no significant difference between the total amount of biomass obtained by centrifugation and membrane microfiltration, i.e. 0.1174 +/- 0.0308 and 0.1145 +/- 0.0268g, respectively. Almost the same total lipid content was obtained using both methods, i.e. 27.96 +/- 0.77 and 26.43 +/- 0.67% for centrifugation and microfiltration, respectively. However, harvesting by coagulation resulted in the lowest biomass and lipid content. Similar fatty acid profiles were obtained for all of the harvesting methods, indicating that the main components were palmitic acid (C16:0), oleic acid (C18:1) and linoleic acid (C18:2). However, the amounts of the individual fatty acids were higher for microfiltration than for centrifugation and coagulation; coagulation performed the most poorly in this regard by producing the smallest amount of fatty acids (41.61 +/- 6.49mg/gdw). The harvesting method should also be selected based on the cost benefit and energy requirements. The membrane filtration method offers the advantages of currently decreasing capital costs, a high efficiency and low maintenance and energy requirements and is thus the most efficient method for microalgae harvesting.
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  111. 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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  112. 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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  113. Characterization of the acylglycerols and resulting biodiesel derived from vegetable oil and microalgae (Thalassiosira pseudonana and Phaeodactylum tricornutum)
    Abstract

    Zendejas, F. J.; Benke, P. I.; Lane, P. D.; Simmons, B. A.; Lane, T. W. 2012. Characterization of the acylglycerols and resulting biodiesel derived from vegetable oil and microalgae (Thalassiosira pseudonana and Phaeodactylum tricornutum). Biotechnology and Bioengineering. 109(5) 1146-1154

    Algal biofuels are a growing interest worldwide due to their potential in terms of sustainable greenhouse gas displacement and energy production. This article describes a comparative survey of biodiesel production and conversion yields of biodiesel via alkaline transesterification of acylglycerols extracted from the microalgae Thalassiosira pseudonana and Phaeodactylum tricornutum, grown under silicate or nitrate limitation, and that of model vegetable oils: soybean, and rapeseed oil. Acylglycerols were extracted with n-hexane and the total yield per biomass was determined by gravimetric assay. Under our conditions, the total acylglycerol yield from the microalgae studied was 1318% of total dry weight. The biodiesel samples were analyzed using gas chromatographyflame ionization detector to determine quantitative information of residual glycerol, mono-, di-, and tri-acylglycerol concentrations in the biodiesel. All of the algal-based biodiesel demonstrated less mono-, di-, and tri-acylglycerol concentrations than the vegetable-based biodiesel under identical transesterification conditions. The fatty acid compositions of all the feedstock oils and their resultant biodiesel were also analyzed and reported. Based on the fatty acid methyl ester compositions of our samples we qualitatively assessed the suitability of the algal-derived biodiesel in terms of cetane number (CN), cold-flow properties, and oxidative stability. Biotechnol. Bioeng. 2012;109: 11461154. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.
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  114. Characterization of Microalgae for the Purpose of Biofuel Production
    Abstract

    Bi, Z.; He, B. B. 2013. Characterization of Microalgae for the Purpose of Biofuel Production. Transactions of the Asabe. 56(4) 1529-1539

    It is now widely accepted that microalgae are promising candidate feedstocks for biofuel production, especially for biodiesel. Microalgae consist of a vast number of species that contain complex chemical constituents and physical structures. The purpose of this study is to understand the physical and chemical properties of selected microalgae, which is critical to the design of appropriate processes for commercial biofuel production. ASTM standard methods were implemented to examine the microalgae properties, including proximate and ultimate analyses. Among the microalgae studied, green microalgae have more volatile matter than brown microalgae, while the latter contain much higher ash content (as high as 43.4%wt +/- 0.20%wt dry basis). The lowest ash content was found in the samples of green microalgae (14.3%wt +/- 0.10%wt dry basis). Ultimate analysis showed that brown microalgae have less carbon content (approx. 25%wt dry basis) as compared to green microalgae (49%wt to 58%wt dry basis). All samples of microalgae were high in sulfur content (0.4%wt to 1.0%wt dry basis). Mineral contents of all microalgal samples were similar to those commonly present in other biomass. Brown microalgae contain significantly higher amounts of carbohydrates (72.9%wt to 75.5%wt dry basis) than green microalgae. On the other hand, green microalgae contain more crude fat (17.1%wt to 27.8%wt dry basis) than brown microalgae. The fatty acid profiles show that the primary fatty acids in microalgal lipids are similar to those of vegetable oils such as soybean oil. However, there are also many odd-numbered fatty acids, such as C15:0, C17:0, and C19:0, which are not typically seen in other seed oils.
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  115. 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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  116. Carbon Neutral Biodiesel Production from Microalgae: Perspectives and Advances
    Abstract

    Khan, S. A.; Rashmi 2011. Carbon Neutral Biodiesel Production from Microalgae: Perspectives and Advances. Algae Biofuel. 241-263

    Continued use of petroleum-based fuels is now widely recognized as unsustainable because of depleting supplies/stocks and the contribution of these fuels to pollute the environment. There has been greater awareness on biodiesel in India in the recent times due to scarcity of petrodiesel and soaring prices. One possible alternative to fossil fuel is the use of oils of plant origin like vegetable oils, algal biomass and tree borne oil seeds. Usage of biodiesel will allow a balance to be sought between agriculture, economic development and the environment. Unfortunately, biodiesel from oil crops, waste cooking oil and animal fat cannot realistically satisfy even a small fraction of the existing demand for fuels. Recent research initiatives have proven that microalgae biomass appear to be the one of the promising source of renewable biodiesel which is capable of meeting the global demand for transport fuels. Microalgae are photosynthetic microorganisms which convert sunlight, water and carbon dioxide to sugars, from which biological macromolecules, such as lipids and triacylglycerol (TAG) can be obtained. The TAG content of some microalgae is so high and can be promising sustainable feedstock for biodiesel production. Using microalgae to produce biodiesel will not compromise production of food, fodder and other products derived from crops. Producing microalgal biomass is generally more expensive than growing crops but it can be reduced substantially by using a biorefinery based production strategy. Microalgal-based carbon sequestration technologies can, in principle, not only cover the cost of carbon capture and sequestration but also produce environment friendly biodiesel. So, Biodiesel from microalgae could be an environmentally benign solution for energy security & rural economy of India.
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  117. The carbon footprint and non-renewable energy demand of algae-derived biodiesel
    Abstract

    Azadi, P.; Brownbridge, G.; Mosbach, S.; Smallbone, A.; Bhave, A.; Inderwildi, O.; Kraft, M. 2014. The carbon footprint and non-renewable energy demand of algae-derived biodiesel. Applied Energy. 1131632-1644

    We determine the environmental impact of different biodiesel production strategies from algae feedstock in terms of greenhouse gas (GHG) emissions and non-renewable energy consumption, we then benchmark the results against those of conventional and synthetic diesel obtained from fossil resources. The algae cultivation in open pond raceways and the transesterification process for the conversion of algae oil into biodiesel constitute the common elements among all considered scenarios. Anaerobic digestion and hydrothermal gasification are considered for the conversion of the residues from the wet oil extraction route; while integrated gasification-heat and power generation and gasification-Fischer-Tropsch processes are considered for the conversion of the residues from the dry oil extraction route. The GHG emissions per unit energy of the biodiesel are calculated as follows: 41 g e-CO2/MJ(b) for hydrothermal gasification, 86 g e-CO2/MJ(b) for anaerobic digestion, 109 g e-CO2/MJ(b) for gasification-power generation, and 124 g e-CO2/MJ(b) for gasification-Fischer-Tropsch. As expected, non-renewable energy consumptions are closely correlated to the GHG values. Also, using the High Dimensional Model Representation (HDMR) method, a global sensitivity analysis over the entire space of input parameters is performed to rank them with respect to their influence on key sustainability metrics. Considering reasonable ranges over which each parameter can vary, the most influential input parameters for the wet extraction route include extractor energy demand and methane yield generated from anaerobic digestion or hydrothermal gasification of the oil extracted-algae. The dominant process input parameters for the dry extraction route include algae oil content, dryer energy demand, and algae annual productivity. The results imply that algal biodiesel production from a dried feedstock may only prove sustainable if a low carbon solution such as solar drying is implemented to help reducing the water content of the feedstock. (C) 2013 Elsevier Ltd. All rights reserved.
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  118. Biotechnological applications of microalgae biodiesel and value added products
    Abstract

    Bux, F. 2013. Biotechnological applications of microalgae biodiesel and value added products. . 1 online resource (pages cm

    "The book gives an in-depth analysis of microalgal biology, ecology, biotechnology and biofuel production capacity as well as a thorough discussion on the value added products that can be generated from diverse microalgae. It summarizes the state of the art in microalgal biotechnology research, from microalgal strain selection, microbiology, cultivation, harvesting, and processing. Contributors from the US, Africa, Asia, South America, and Europe cover microalgal physiology, biochemistry, ecology, molecular biology, and more"--
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  119. Biotechnological applications of microalgae : biodiesel and value added products
    Abstract

    Bux, F. 2013. Biotechnological applications of microalgae : biodiesel and value added products. . xv, 239 pages

    "The book gives an in-depth analysis of microalgal biology, ecology, biotechnology and biofuel production capacity as well as a thorough discussion on the value added products that can be generated from diverse microalgae. It summarizes the state of the art in microalgal biotechnology research, from microalgal strain selection, microbiology, cultivation, harvesting, and processing. Contributors from the US, Africa, Asia, South America, and Europe cover microalgal physiology, biochemistry, ecology, molecular biology, and more"--
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  120. Biomass and lipid production of heterotrophic microalgae Chlorella protothecoides by using biodiesel-derived crude glycerol
    Abstract

    Chen, Y. H.; Walker, T. H. 2011. Biomass and lipid production of heterotrophic microalgae Chlorella protothecoides by using biodiesel-derived crude glycerol. Biotechnology Letters. 33(10) 1973-1983

    Microalgal lipids may be a more sustainable biodiesel feedstock than crop oils. We have investigated the potential for using the crude glycerol as a carbon substrate. In batch mode, the biomass and lipid concentration of Chlorella protothecoides cultivated in a crude glycerol medium were, respectively, 23.5 and 14.6 g/l in a 6-day cultivation. In the fed-batch mode, the biomass and lipid concentration improved to 45.2 and 24.6 g/l after 8.2 days of cultivation, respectively. The maximum lipid productivity of 3 g/l day in the fed-batch mode was higher than that produced by batch cultivation. This work demonstrates the feasibility of crude biodiesel glycerol as an alternative carbon substrate to glucose for microalgal cultivation and a cost reduction of carbon substrate feed in microalgal lipid production may be expected.
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  121. Biodiesel synthesis from microalgae using immobilized Aspergillus niger whole cell lipase biocatalyst
    Abstract

    Guldhe, A.; Singh, P.; Kumari, S.; Rawat, I.; Permaul, K.; Bux, F. 2016. Biodiesel synthesis from microalgae using immobilized Aspergillus niger whole cell lipase biocatalyst. Renewable Energy. 851002-1010

    Whole cell lipase catalysis and microalgal feedstocks make overall biodiesel synthesis greener and sustainable. In this study, a novel approach of whole cell lipase-catalyzed conversion of Scenedesmus obliquus lipids was investigated for biodiesel synthesis. Microalgal biodiesel was characterized for its fuel properties. Optimization of process parameters for immobilized Aspergillus niger whole cell lipase-catalyzed biodiesel synthesis was carried out. Highest biodiesel conversion of 53.76% was achieved from S. obliquus lipids at 35 degrees C, methanol to oil ratio of 5:1 and 2.5% water content based on oil weight with 6 BSPs (Biomass support particles). Step-wise methanol addition was applied to account for methanol tolerance, which improved biodiesel conversion upto 80.97% and gave 90.82 +/- 1.43% yield. Immobilized A. niger lipase can be used for 2 batches without significant loss in conversion efficiency. Most of the fuel properties of biodiesel met the specifications set by international standards. (c) 2015 Elsevier Ltd. All rights reserved.
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  122. Biodiesel production with microalgae as feedstock: from strains to biodiesel
    Abstract

    Gong, Y. M.; Jiang, M. L. 2011. Biodiesel production with microalgae as feedstock: from strains to biodiesel. Biotechnology Letters. 33(7) 1269-1284

    Due to negative environmental influence and limited availability, petroleum-derived fuels need to be replaced by renewable biofuels. Biodiesel has attracted intensive attention as an important biofuel. Microalgae have numerous advantages for biodiesel production over many terrestrial plants. There are a series of consecutive processes for biodiesel production with microalgae as feedstock, including selection of adequate microalgal strains, mass culture, cell harvesting, oil extraction and transesterification. To reduce the overall production cost, technology development and process optimization are necessary. Genetic engineering also plays an important role in manipulating lipid biosynthesis in microalgae. Many approaches, such as sequestering carbon dioxide from industrial plants for the carbon source, using wastewater for the nutrient supply, and maximizing the values of by-products, have shown a potential for cost reduction. This review provides a brief overview of the process of biodiesel production with microalgae as feedstock. The methods associated with this process (e.g. lipid determination, mass culture, oil extraction) are also compared and discussed.
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  123. 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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  124. 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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  125. 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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  126. 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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  127. 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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  128. 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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  129. 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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  130. 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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  131. 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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  132. 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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  133. 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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  134. 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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  135. Biodiesel from oilgae, biofixation of carbon dioxide by microalgae: A solution to pollution problems
    Abstract

    Demirbas, A. 2011. Biodiesel from oilgae, biofixation of carbon dioxide by microalgae: A solution to pollution problems. Applied Energy. 88(10) 3541-3547

    Algae containing 30-75% of lipid by dry basis can be called oilgae. All microalgac species produce lipid however some species can contain up to 70% of their dry weight. Microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels. Biodiesel production by using oilgac is an alternative process in contrast to other procedures not only being degradable and non-toxic but also as a solution to global warming via reducing emission gases. Algae-based technologies could provide a key tool for reducing greenhouse gas emissions from coal-fired power plants and other carbon intensive industrial processes. Because algae are rich in oil and can grow in a wide range of conditions, many companies are betting that it can create fuels or other chemicals cheaper than existing feedstocks. The aim of microalgae biofixation of CO2 is to operate large-scale systems that are able to convert a significant fraction of the CO2 outputs from a power plant into biofuels. (C) 2011 Elsevier Ltd. All rights reserved.
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  136. Biodiesel from mixed culture algae via a wet lipid extraction procedure
    Abstract

    Sathish, A.; Sims, R. C. 2012. Biodiesel from mixed culture algae via a wet lipid extraction procedure. Bioresource Technology. 118643-647

    Microalgae are a source of renewable oil for liquid fuels. However, costs for dewatering/drying, extraction, and processing have limited commercial scale production of biodiesel from algal biomass. A wet lipid extraction procedure was developed that was capable of extracting 79% of transesterifiable lipids from wet algal biomass (84% moisture) via acid and base hydrolysis (90 degrees C and ambient pressures), and 76% of those extracted lipids were isolated, by further processing, and converted to FAMEs. Furthermore, the procedure was capable of removing chlorophyll contamination of the algal lipid extract through precipitation. In addition, the procedure generated side streams that serve as feedstocks for microbial conversion to additional bioproducts. The capability of the procedure to extract lipids from wet algal biomass, to reduce/remove chlorophyll contamination, to potentially reduce organic solvent demand, and to generate feedstocks for high-value bioproducts presents opportunities to reduce costs of scaling up algal lipid extraction for biodiesel production. (C) 2012 Elsevier Ltd. All rights reserved.
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  137. Biodiesel from Microalgae, Yeast, and Bacteria: Engine Performance and Exhaust Emissions
    Abstract

    Wahlen, B. D.; Morgan, M. R.; McCurdy, A. T.; Willis, R. M.; Morgan, M. D.; Dye, D. J.; Bugbee, B.; Wood, B. D.; Seefeldt, L. C. 2013. Biodiesel from Microalgae, Yeast, and Bacteria: Engine Performance and Exhaust Emissions. Energy & Fuels. 27(1) 220-228

    Biodiesels (fatty acid methyl esters) derived from oleaginous microbes (microalgae, yeast, and bacteria) are being actively pursued as potential renewable substitutes for petroleum diesel. Here, we report the engine performance characteristics of biodiesel produced from a microalgae (Chaetoceros gracilis), a yeast (Cryptococcus curvatus), and a bacteria (Rhodococcus opacus) in a two-cylinder diesel engine outfitted with an eddy current brake dynamometer, comparing the fuel performance to petroleum diesel (#2) and commercial biodiesel from soybeans. Key physical and chemical properties, including heating value, viscosity, density, and cetane index, for each of the microbial-derived biofuels were found to compare favorably to those of soybean biodiesel. Likewise, the horsepower, torque, and brake specific fuel consumption across a range of engine speeds also compared favorably to values determined for soybean biodiesel. Analysis of exhaust emissions (hydrocarbon, CO, CO2, O-2, and NOx) revealed that all biofuels produced significantly less CO and hydrocarbon than petroleum diesel. Surprisingly, microalgae biodiesel was found to have the lowest NOx output, even lower than petroleum diesel. The results are discussed in the context of the fatty acid composition of the fuels and the technical viability of microbial biofuels as replacements for petroleum diesel.
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  138. Assessment of diesel engine performance when fueled with biodiesel from algae and microalgae: An overview
    Abstract

    Piloto-Rodriguez, R.; Sanchez-Borroto, Y.; Melo-Espinosa, E. A.; Verhelstb, S. 2017. Assessment of diesel engine performance when fueled with biodiesel from algae and microalgae: An overview. Renewable & Sustainable Energy Reviews. 69833-842

    Biofuels derived from algae can have lower impact on the environment and the food supply than biofuels produced from crops. The strain selection, cultivation method, culture conditions and the chemical composition strongly influences the production costs but also the engine's performance and the exhaust gas emissions. The scope of this paper is to make a critical review about the impact of the use of biofuels produced from (micro) algae to power diesel engines. There is a huge disparity in the amount of papers published for algae culture, oil extraction, and biodiesel production compared to reporting performance on diesel engines. This paper presents an analysis of the papers published in this specific field. Generally, a reduction of torque and power output is reported. A wide range of blends up to B50 but also pure biodiesel has been tested. The blend showing results closest to diesel fuel appears to be B20. Several pollutants can be reduced if biofuels from different strains are used but an increase in NOx is generally reported, associated to higher temperatures in the combustion chamber. The use of emulsions instead of blends or neat biodiesel reveals a promising alternative with important reductions of CO2 and NOx. However, the few reports for engine tests present some contradictions, or are lacking important information about the experiments. The assessment of biodiesel produced from algae or microalgae is a field hardly explored and until today some reference papers contain contradictory results or non well studied behaviors as this survey demonstrates.
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  139. Assessment of algae biodiesel viability based on the area requirement in the European Union, United States and Brazil
    Abstract

    Speranza, L. G.; Ingram, A.; Leeke, G. A. 2015. Assessment of algae biodiesel viability based on the area requirement in the European Union, United States and Brazil. Renewable Energy. 78406-417

    The replacement of diesel by biofuels is considered unrealistic because of the land used to produce their feedstock. One appointed solution is the use of algae which have higher productivity per unit area when compared with other feedstocks. In light of this, the total area, including water and land required for the European Union (EU), the United States (US), and Brazil was determined using international policies and targets, the present and future diesel demand, the current biodiesel production (released by international organizations), and specific data of algae productivity from the literature.
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  140. Assessing the Potential of Some Freshwater and Saline Microalgae as Biodiesel Feedstock
    Abstract

    Selvarajan, R.; Felfoldi, T.; Sanniyasi, E.; Tekere, M. 2016. Assessing the Potential of Some Freshwater and Saline Microalgae as Biodiesel Feedstock. Journal of Biobased Materials and Bioenergy. 10(1) 50-62

    Microalgae have attracted a major interest in biofuel, food and feed stock sectors as they can accumulate lipids, proteins and carbohydrates in large amounts within short periods of time. The selection of the most suitable algal species for biofuel production is based on key parameters such as lipids, fatty acids composition and characteristics. This paper describes the bioprospecting and molecular screening of 21 microalgal strains isolated from different fresh and saline water habitats by analysing their biomass, lipids and fatty acid profiles, used for estimating biodiesel properties. Biomass productivity amongst the strains varied from 142.5 +/- 13.4 to 622.8 +/- 14.0 mg/L. Seven strains viz. Acutodesmus sp. TST2, Scenedesmus sp. PK1, Desmodesmus armatus TTT1, Desmodesmus armatus FW005, Neochloris sp. RP2, Stichococcus bacillaris LU1 and Hegewaldia sp. LC1 showed a lipid mass fraction of >25% on a dry basis. Fatty acid profiling showed that fatty acids with carbon chain length of C16-C18 such as palmitic, oleic and linoleic acids were major fatty acids in all the isolated species. Three strains viz. Acutodesmus sp. TST2, Stichococcus bacillaris LU1 and Hegewaldia sp. LC1 accumulated high lipid content (>28% dwt), with higher levels of fatty acid profiles of C16-C18 (>70%) indicating their potential as sources of biodiesel with suitable biodiesel properties of high cetane number (57-59), low viscosity (4.73-4.85 mm(2)/s), lower iodine value (54.4-68.5 gl(2)/100 g), relative cloud point (9-13 degrees C) and negative cold filter plugging point (-2 to -6 degrees C) in accordance with international standards.
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  141. 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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  142. 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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  143. 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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  144. Algae biodiesel life cycle assessment using current commercial data
    Abstract

    Passell, H.; Dhaliwal, H.; Reno, M.; Wu, B.; Ben Amotz, A.; Ivry, E.; Gay, M.; Czartoski, T.; Laurin, L.; Ayer, N. 2013. Algae biodiesel life cycle assessment using current commercial data. Journal of Environmental Management. 129103-111

    Autotrophic microalgae represent a potential feedstock for transportation fuels, but life cycle assessment (LCA) studies based on laboratory-scale or theoretical data have shown mixed results. We attempt to bridge the gap between laboratory-scale and larger scale biodiesel production by using cultivation and harvesting data from a commercial algae producer with similar to 1000 m(2) production area (the base case), and compare that with a hypothetical scaled up facility of 101,000 m(2) (the future case). Extraction and separation data are from Solution Recovery Services, Inc. Conversion and combustion data are from the Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation Model (GREET). The LCA boundaries are defined as "pond-to-wheels". Environmental impacts are quantified as NER (energy in/ energy out), global warming potential, photochemical oxidation potential, water depletion, particulate matter, and total NOx and SOx. The functional unit is 1 MJ of energy produced in a passenger car. Results for the base case and the future case show an NER of 33.4 and 1.37, respectively and GWP of 2.9 and 0.18 kg CO2-equivalent, respectively. In comparison, petroleum diesel and soy diesel show an NER of 0.18 and 0.80, respectively and GWP of 0.12 and 0.025, respectively. A critical feature in this work is the low algal productivity (3 g/m(2)/day) reported by the commercial producer, relative to the much higher productivities (20-30 g/m(2)/day) reported by other sources. Notable results include a sensitivity analysis showing that algae with an oil yield of 0.75 kg oil/kg dry biomass in the future case can bring the NER down to 0.64, more comparable with petroleum diesel and soy biodiesel. An important assumption in this work is that all processes are fully co-located and that no transport of intermediate or final products from processing stage to stage is required. (C) 2013 Elsevier Ltd. All rights reserved.
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  145. Advantages and Challenges of Microalgae as a Source of Oil for Biodiesel
    Abstract

    Griffiths, M. J.; Dicks, R. G.; Richardson, C.; Harrison, S. T. L. 2011. Advantages and Challenges of Microalgae as a Source of Oil for Biodiesel. Biodiesel - Feedstocks and Processing Technologies. 177-200

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