Mixotrophic cultivation enhances lipid productivity and fatty acid profile towards efficient production of microalgae-based biofuel from Desmodesmus sp. DLK

The selection of an appropriate strain is important for the sustainability of algae-based oil industries. In the current study, a novel omega-3 fatty acid-rich microalgal strain was isolated and identified as Desmodesmus sp. Dal Lake Kashmir (DLK) based on its morphology and molecular characterization. Its potential as biofuel feedstock was established based on its appropriate fatty acid profile and enhanced lipid productivity. The growth of Desmodesmus sp. DLK was evaluated using varying concentrations of three exogenous carbon sources (glucose, glycerol and sodium acetate) to examine the potential of the freshwater microalga to ameliorate biomass and lipid production for proficient biofuel production. A phenomenal enhancement in biomass productivity (12.8-fold) and lipid productivity (22-fold) was detected with 1% glucose in comparison to control. Supplementation with glycerol boosted the productivity of biomass and lipid maximum by 11.4-fold (5 g.L-1 gly) and 26.8-fold (10 g.L-1 gly), respectively. Analyses of fatty acid methyl esters from mixotrophically grown culture, via gas chromatography and mass spectrometry, exhibited a prevalence of palmitic acid (C16:0; 37%) and oleic acid (C18:1; 53%) demonstrating desirable properties for biofuel quality. This study highlights that the mixotrophic cultivation of Desmodesmus sp. DLK redirects algal metabolite fluxes towards the production of improved lipids, suitable for biofuel production.