Biochemical characterization of indigenous green microalgae and FAMEs profiling of lipids for sustainable biodiesel production

There is a growing need for sustainable energy sources, which has led to increased interest in microalgae as a feedstock for the production of biodiesel. This study investigated indigenous green microalgae for biodiesel generation through comprehensive biochemical and analytical evaluations of their biomass. Green microalgae species were cultured in BG-11 medium under controlled photobioreactor conditions, harvested, and analyzed for protein, carbohydrate, lipid, and Carbon-Hydrogen-Nitrogen-Sulphur (CHNS) composition. Nile red staining and Bligh and Dyer extraction revealed lipid content ranging from 11.74 32.17 % and in-situ transesterification and GC-MS profiling quantified fatty acid methyl esters (FAMEs). Chlorella sp. MOW 3 showed the highest yield (4.48 % of biomass). Protein and carbohydrate content varied between 17.76 – 47.43 % and 13.59 – 46.56 %, respectively. The CHNS analysis showed the highest carbon content in Graesiella emersonii MOW 9 (55.55 %). Only lipid content exhibited a statistically significant correlation with the C/N ratio, and the CHNS analysis directly validates lipid metabolic regulation in these isolates. GC-MS analysis revealed saturated, monounsaturated, and polyunsaturated fatty acids, with palmitic acid, oleic acid, and linoleic acid being the most abundant. These findings underscore the viability of indigenous microalgae strains as promising candidates for renewable biodiesel production.