Light intensity and N/P nutrient affect the accumulation of lipid and unsaturated fatty acids by Chlorella sp.

•High lipid content was obtained in control medium under high light intensity.•Lipid and UFA contents were observably enhanced by higher light intensity.•N/P in mediums notably affected the lipid and UFA content.

In this study, different light intensities (80, 160, 240 and 320 μmol/m2 s) and various mediums including control medium (CM), N/P rich medium (NPM), N rich medium (NM), and P rich medium (PM) were applied for cultivation of Chlorella sp. It was revealed that cultivation of Chlorella sp. in CM under the light intensity of 320 μmol/m2 s led to a lipid content up to 30% enhancement, which was higher than the results of other cases. A rather high unsaturated fatty acid (UFA) content of 7.5% and unsaturated fatty acid/total fatty acid (UFA/TFA) ratio of 0.73 were obtained under 320 μmol/m2 s in CM, indicating that the CM-320 system was applicable for the generation of UFA. Moreover, Chlorella sp. cultivated in PM under 320 μmol/m2 s provided higher TFA content (7.3%), which was appropriate for biofuel production.