Assessment of fuel properties on the basis of fatty acid profiles of oleaginous yeast for potential biodiesel production

Over the last decade, there has been a huge upsurge of interest in sustainable production of biomass-based biofuels to fulfill the existing energy demand and simultaneously reducing the environmental deterioration. Earlier, vegetable oils and animal fats were utilized for biodiesel production, but due to food crisis and environmental sustainability, renewable sources such as neutral lipid derived from microbes are gaining much attention for budding biodiesel industries. Among various types of microorganisms, oleaginous yeasts are more promising feedstock to accomplish the current demand of biodiesel production and utilize a large number of cost-effective renewable substrates for their growth and lipid accumulation. However, biodiesel obtained from oleaginous yeasts have certain restrictions regarding their commercial utilization due to their unstable fuel properties such as oxidative stability, cetane number, viscosity and low-temperature performance etc. Numerous articles have been published in the public domain describing the fatty acid profiles of oleaginous yeast as feedstock for biodiesel production. However, the evaluation of quality parameters of biodiesel obtained from oleaginous yeasts is still in infancy. Although there is a huge disparity in a number of papers published for biodiesel production yet the reporting performance on diesel engines need to be verified in details. In this review article, attempt has been made to assess the important biofuel properties on the basis of the fatty acid profile of oleaginous yeast. Thus this evaluation would provide a guideline to the biodiesel producer to improve the production plans related to feedstocks for oleaginous yeast, culture conditions and biodiesel blending

Insights into the Enhanced Lipid Production Characteristics of a Fresh Water Microalga under High Salinity Conditions

Bioprospecting of microalgae capable of growing and accumulating high amounts of lipids in high salinity conditions such as seawater can substantially improve the economic vaibaility of algal biodiesel production. In view of this, a fresh water microalga, <i>Scenedesmus</i> sp. IITRIND2, was cultivated under saline conditions to assess its halotolerant behavior and potential as biodiesel feedstock. The microalga efficiently adapted to 100% seawater salinity, enhanced its lipid content by 52%, thus yielded ∼3.2 fold higher lipid productivity as compared to the Bold’s basal media (BBM). The increase in the lipid content was balanced by a sharp decrease in its protein and carbohydrate content. Biochemical analysis evidenced that salinity induced oxidative stress resulted in reduced levels of photosynthetic pigments, elevated levels of reactive oxygen species (H₂O₂, thiobarbituric acid reactive substances), osmolytes (proline, glycine betaine), and activity of antioxidant enzymes (catalase, ascorbate peroxidase). These studies suggested that microalga efficiently modulated its metabolic flexibility in order to acclatamize the salanity induced stress. Further, the FAME analysis revealed the dominance of C14:0, C16:0, C18:0, C18:1, and C18:2 fatty acids under halotolerant conditions, and the properties of the resulting biodiesel were in compliance with ASTM (American Society for Testing Materials) D6751 and EN 14214 (European) fuel standards. These results consolidate that the lipid augmented halotolerant algal strains capable of growing in saline/seawater can be formulated as environmental sustainable and economic viable sources for biodiesel production