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High Lipid Induction in Microalgae for Biodiesel Production  [PDF]
Kalpesh K. Sharma,Holger Schuhmann,Peer M. Schenk
Energies , 2012, DOI: 10.3390/en5051532
Abstract: Oil-accumulating microalgae have the potential to enable large-scale biodiesel production without competing for arable land or biodiverse natural landscapes. High lipid productivity of dominant, fast-growing algae is a major prerequisite for commercial production of microalgal oil-derived biodiesel. However, under optimal growth conditions, large amounts of algal biomass are produced, but with relatively low lipid contents, while species with high lipid contents are typically slow growing. Major advances in this area can be made through the induction of lipid biosynthesis, e.g., by environmental stresses. Lipids, in the form of triacylglycerides typically provide a storage function in the cell that enables microalgae to endure adverse environmental conditions. Essentially algal biomass and triacylglycerides compete for photosynthetic assimilate and a reprogramming of physiological pathways is required to stimulate lipid biosynthesis. There has been a wide range of studies carried out to identify and develop efficient lipid induction techniques in microalgae such as nutrients stress (e.g., nitrogen and/or phosphorus starvation), osmotic stress, radiation, pH, temperature, heavy metals and other chemicals. In addition, several genetic strategies for increased triacylglycerides production and inducibility are currently being developed. In this review, we discuss the potential of lipid induction techniques in microalgae and also their application at commercial scale for the production of biodiesel.
Arief Widjaja
Makara Seri Teknologi , 2009,
Abstract: Recently, several strains of microalgae have been studied as they contain high lipid content capable to be converted to biodiesel. Fresh water microalgae Chlorella vulgaris studied in this research was one of the proof as it contained high triacyl glyceride which made it a potential candidate for biodiesel production. Factors responsible for good growing of microalgae such as CO2 and nitrogen concentration were investigated. It was found that total lipid content was increased after exposing to media with not enough nitrogen concentration. However, under this nitrogen depletion media, the growth rate was very slow leading to lower lipid productivity. The productivity could be increased by increasing CO2 concentration. The lipid content was found to be affected by drying temperature during lipid extraction of algal biomass. Drying at very low temperature under vacuum gave the best result but drying at 60oC slightly decreased the total lipid content.
Optimization of Nitrogen, Phosphorus and Salt for Lipid Accumulation of Microalgae: Towards the Viability of Microalgae Biodiesel  [PDF]
Carolina T. Miranda, Daniel V. N. de Lima, Georgia C. Atella, Paula F. de Aguiar, Sandra M. F. O. Azevedo
Natural Science (NS) , 2016, DOI: 10.4236/ns.2016.812055
In recent years, microalgae biodiesel has attracted expressive attention and investment, once it was considered a potential resource for energy. Although the wide use of microalgae biodiesel is restricted by its high production cost. For cost-efficient and sustainable production of biodiesel from microalgae, a proper understanding of the variables and their impacts on physiology of the strains is required. In this study, a simple factorial design 23 was used to find optimal conditions for the cultivation of Ankistrodesmus sp. and Chlamydomonas sp. in batch culture. The three components considered were nitrate, phosphate and sodium chloride, used to assess the metabolic versatility of the strains in brackish conditions. The results showed that culture medium with 0.04 g·L?1 nitrate, 0.01 g·L?1 phosphate and 5.0 g·L?1 sodium chloride resulted to be the most effective condition to growth and fatty acids accumulation. Using this optimal condition, Ankistrodesmus sp. and Chlamydomonas sp. increased in 2.1 and 2.4 folds their fatty acids yield, respectively. Importantly, this protocol reduced 75% of the nitrate and phosphate concentrations of the original medium (ASM-1). Additionally, fatty acids analysis found that these strains were mainly constituted of C16-C18, in accordance with the requirements for biodiesel production. The simple factorial design applied here proved to be an important tool towards a better understanding of synergistic effects of tested factors on microalgae metabolism, and the resulting information could be used effectively to improve microalgae cultivation.
Current Status and Prospects of Biodiesel Production from Microalgae  [PDF]
Xiaodan Wu,Rongsheng Ruan,Zhenyi Du,Yuhuan Liu
Energies , 2012, DOI: 10.3390/en5082667
Abstract: Microalgae represent a sustainable energy source because of their high biomass productivity and ability to remove air and water born pollutants. This paper reviews the current status of production and conversion of microalgae, including the advantages of microalgae biodiesel, high density cultivation of microalgae, high-lipid content microalgae selection and metabolic control, and innovative harvesting and processing technologies. The key barriers to commercial production of microalgae biodiesel and future perspective of the technologies are also discussed.
Nkongolo Mulumba,Ihab H. Farag
International Journal of Engineering Science and Technology , 2012,
Abstract: Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year). However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR) was designed and achieved a ten times increase in algae concentration. It produced 1g of dry algal biomass per liter of medium within 12 days, with a lipid content of 12% approximately. Healthy algal culture grew well in the TPBR reaching 56x106 cells/mL of culture medium. The 10 fold increase is higher than those reported for open ponds and helical photobioreactor.
Microalgae Isolation and Selection for Prospective Biodiesel?Production  [PDF]
Van Thang Duong,Yan Li,Ekaterina Nowak,Peer M. Schenk
Energies , 2012, DOI: 10.3390/en5061835
Abstract: Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products are now being considered for commercial production which necessitates the selection of the most capable algae strains suitable for multiple-product algae biorefineries. Here we present and review practical issues of several simple and robust methods for microalgae isolation and selection for traits that maybe most relevant for commercial biodiesel production. A combination of conventional and modern techniques is likely to be the most efficient route from isolation to large-scale cultivation.
Screening of Microalgae for Biodiesel Feedstock  [PDF]
Xi Chen, Guoqiang He, Zhiping Deng, Nan Wang, Wei Jiang, Sanfeng Chen
Advances in Microbiology (AiM) , 2014, DOI: 10.4236/aim.2014.47044

Three heterotrophic microalgae identified as Scenedesmus sp. Y5, Scenedesmus sp. Y7 and Chorellasp. Y9 were isolated and screened from natural water based on biomass yield and lipid productivity. Fatty acids’ composition analysis showed that both Y5 and Y7 mainly contained C16:0, C18:1 (n - 9), C18:2 (n - 6) and C18:3 (n - 3) and Y9 mainly contained C16:0, C18:0 and C18:2 (n - 6), suggesting that these microalgae can be ideal feedstock for biodiesel. Considering the specific growth rate and lipid productivity, the culture conditions were optimized for Scenedesmus sp. Y5, Scenedesmus sp. Y7 and Chorellasp. Y9. Based on the optimization of cultural conditions, all of these three microalgae were tested in fed-batch fermentation, and their biomass productivities were 4.960 g·L-1·d-1, 5.907 g·L-1·d-1 and 4.038 g·L-1

Microalgae of Odisha Coast as a Potential Source for Biodiesel Production
World Environment , 2012, DOI: 10.5923/j.env.20120201.03
Abstract: In recent years microalgae have been proved as the potential source for biodiesel production due to high oil content. In the present study three brackish water microalgal strains (Chlorococcum sp., Chlorella sp. and Scenedesmus sp.) of Odisha coast were screened for the suitability for biodiesel production. Among all, Scenedesmus sp. seems to be the best one for high lipid productivity (24.66mg/L/day) with high biomass yield of 0.9g/L at stationary phase. Also the Scenedesmus sp. possesses the most adequate fatty acid profile. The present study suggested that Scenedesmus sp. is appropriate for biodiesel production for its high lipid content; this strain was selected for higher scale studies.
Potency of Microalgae as Biodiesel Source in Indonesia  [cached]
H Hadiyanto,W Widayat,Andri Cahyo Kumoro
International Journal of Renewable Energy Development (IJRED) , 2012,
Abstract: Within 20 years, Indonesia should find another energy alternative to substitute current fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17% of our energy mix program. Even though, most of the area in Indonesia is covered by sea, however the utilization of microalgae as biofuel production is still limited. The biodiesel from current sources (Jatropha, palm oil, and sorghum) is still not able to cover all the needs if the fossil oil cannot be explored anymore. In this paper, the potency of microalgae in Indonesia was analysed as the new potential of energy (biodiesel) sources.
Cultivating Microalgae in Domestic Wastewater for Biodiesel Production  [cached]
Notulae Scientia Biologicae , 2012,
Abstract: The objective of this study was to evaluate the growth of nine species of microalgae (green and blue green microalgae) on domestic waste water samples obtained from Zenein Waste Water Treatment Plant (ZWWTP), Giza governorate, Egypt. The species were cultivated in different kind of waste water; before treatment; after sterilization; with nutrients with sterilization and with nutrients without sterilization. The experiment was conducted in triplicate and cultures were incubated at 25±1°C under continuous shaking (150 rpm) and illumination (2000 Lux) for 15 days. pH, electric conductivity (EC), optical density (OD) , dry weight (DW), were done at the time of incubation and at the end of experiment, in addition to determine the percentage of lipid and biodiesel. The data revealed that, domestic waste water with nutrient media (T3) was promising for cultivation of five algal species when compared with conventional media, Moreover, domestic waste water after sterilization (T2) was selected media for cultivation of Oscillatoria sp and Phormedium sp. However, T1 media (waste water without treatment) was the promising media for cultivation of Nostoc humifusum. The biodiesel produced from algal species cultivated in waste water media ranged from 3.8 to 11.80% when compared with the conventional method (3.90 to 12.52%). The results of this study suggest that growing algae in nutrient rich media offers a new option of applying algal process in ZWWTP to mange the nutrient load for growth and valuable biodiesel feedstock production.
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