Effect of CO2 supply conditions on lipid production of Chlorella vulgaris from enzymatic hydrolysates of lipid-extracted microalgal biomass residues

The hydrolysates from lipid-extracted microalgal biomass residues (LMBRs) were used as a source of nutrients for the cultivation of Chlorella vulgaris for lipid production under various CO2 supply conditions, including different CO2 concentrations and aeration rates. Both parameters had a significant effect on lipid production. A CO2 concentration of 5% was found to be most suitable for microalgal growth. Microalga grew best at a CO2 aeration rate of 0.5 vvm. At this rate, biomass concentration and lipid productivity were at a maximum of 3.83 g L−1 and 157 mg L−1 d−1, respectively, but decreased at lower or higher aeration rates. The present results showed that LMBRs utilization was effective in microalgal lipid production under suitable CO2 supply conditions.

► CO2 supply conditions had a significant effect on lipid production.
► The most suitable CO2 concentration for microalgal growth was 5%.
► Microalga grew best at a CO2 aeration rate of 0.5 vvm.
► The fatty acids of the microalga are suitable for biodiesel production.