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. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.