Synergistic supplementation of organic carbon substrates for upgrading neutral lipids and fatty acids contents in microalga

Abstract

Phototrophic and mixotrophic cultivation of C. vulgaris for ameliorating biomass yield, lipid content, neutral lipid content and fatty acid composition was investigated. Phototrophic cultivation of C. vulgaris produced 1.28 g/L dry cell weight and 15.3% lipid content on day 18 whereas in mixotrophic mode of cultivation, acetate at 0.4% has yielded higher dry cell weight of 2.7 g/L and 20.8% lipids compared to dextrose and bicarbonate. Central composite design (CCD) based optimization showed combined supplementation of 0.4% acetate + 0.6% dextrose has accumulated higher lipid content of 27% and 69% neutral lipid compared to acetate + bicarbonate, and dextrose + bicarbonate conditions. Further, fatty acid composition of acetate + dextrose supplemented cells possessed high levels of C16:0, C16:1 and C18:1, which makes mixotrophically cultivated C. vulgaris for pilot-scale production.