Because of high lipid productivity and potential cultivation in non-fertile areas, microalgae has been renowned as a reliable resource for biodiesel production and various high-value bioactive compounds. They can grow rapidly, synthesize, and accumulate large amounts (20–50% of dry weight) of neutral lipids (mainly in the form of triacylglycerol, TAG). The production of lipids, carotenoids, and algal biomass can be enhanced by inducing various environmental stress factors. The present study investigates on effect of nutrient limitation on biomass and lipid production of freshwater microalgae Grasiella sp. and Chlorella sp. under two different conditions of cultivation viz. normal and nutrient limited conditions. Stress was induced in the form of nitrogen and phosphorous deficiency in the cultivation media. Results found that biomass obtained from nutrient-limited conditions was comparatively higher than normal. The dry weight of biomass for Chlorella sp. under normal and nutrient-limited conditions was found to be 0.78 g/L and 0.96 g/L, respectively, and Grasiella sp. 0.48 g/L and 0.8 g/L respectively. FT-IR analysis revealed nutrient limitation influence the change in the biochemical composition in the biomass and varied between the species. Total lipid content for Grasiella sp. KACC 19 under normal and nutrient limited conditions were found to be 0.0131 g/L and 0.0765 g/L, and Chlorella sp. KACC 21 was found to be 0.1125 g/L and 0.2178 g/L respectively. The fatty acid profiling revealed the presence of saturated and MUFA and accumulation of those fatty acids in nutrient-limited condition thereby considered these microalgae as a potential feedstock for the production of biofuel.
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