Effect of carbon source on growth and lipid accumulation in <Emphasis Type="Italic">Chlorella sorokiniana</Emphasis> GXNN01

Heterotrophic culture of microalgae to develop methods of increasing biomass productivity and storage lipids has brought new insight to commercial biodiesel production. To understand the relationship between heterotrophy and lipid production, the effects of carbon sources on the growth and lipid accumulation of Chlorella sorokiniana GXNN01 was studied. The alga exhibited an increased growth rate in response to the addition of carbon sources, which reached the stationary phase after 48 h at 30°C. In addition, glucose and NaAc had a significant effect on the lipid accumulation during the early-stationary phase. Specifically, the lipid content was 0.237±0.026 g g⁻¹ cell dry weight and 0.272±0.041 g L⁻¹ when glucose was used as the carbon source, whereas the lipid content reached 0.287±0.018 g g⁻¹ cell dry weight and 0.288±0.008 g L⁻¹ when NaAc was used as the carbon source. The neutral lipid content was found to first decrease and then increase over time during the growth phase. A glucose concentration of 20 mmol L⁻¹ gave the maximal lipid yield and the optimum harvest time was the early-stationary phase.