Effects of mixotrophic cultivation on antioxidation and lipid accumulation of Chlorella vulgaris in wastewater treatment

The effects of mixotrophic cultivation on antioxidation and lipid production of Chlorella vulgaris in wastewater treatment were analyzed. The biomass and lipid content of the mixotrophic C. vulgaris cultured in wastewater were higher compared with the autotrophic C. vulgaris cultured in BG-11. The mixotrophic C. vulgaris provided more fatty acids as the contents of total fatty acids rose. The unsaturated fatty acid/total fatty acid ratio under mixotrophic cultivation was up to 0.91, indicating the mixotrophic cultivation system was applicable for the generation of unsaturated fatty acids. Activities of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase were improved after the addition of wastewater to algal cultures. Moreover, the activity and starch formation of ADP-glucose pyrophosphorylase decreased and the activity of acetyl-CoA carboxylase was enhanced, which contributed to the lipid production in the mixotrophic C. vulgaris in wastewater. This study suggests mixotrophic cultivation of microalgae in wastewater is an efficient way to improve lipid production.