Lipid production of Chlorella vulgaris from lipid-extracted microalgal biomass residues through two-step enzymatic hydrolysis

Lipid-extracted microalgal biomass residues (LMBRs) were treated using cellulase, neutrase and alcalase in a two-step process and the resulting hydrolysates were used as a source of nutrients for the cultivation of Chlorella vulgaris under non-aerated and aerated conditions for lipid production. Aeration was favorable for cell growth and lipid accumulation and a biomass of approximately 3.28 g L−1, lipid content of 35% and lipid productivity of 116 mg L−1 d−1 were obtained. Thus, the tested mode of LMBRs utilization was effective for nutrient recycling in microalgal biodiesel production.

► A two-step enzymatic hydrolysis method is established. ► Lipid-extracted microalgal biomass residues are converted to amino acids and sugars. ► The maximum biomass is 3.28 g L−1 and highest lipid productivity is 116 mg L−1d−1. ► Results verify a mode for nutrient recycling in microalgal biodiesel production.