Enhancing lutein production with Chlorella sorokiniana Mb-1 by optimizing acetate and nitrate concentrations under mixotrophic growth

Lutein is a xanthophyll pigment known for its antioxidant activities and its protective role against eye damage. In this study, lutein production from microalgae with mixotrophic cultivation is demonstrated. Four acetate-utilizing microalgae with high lutein accumulating ability were isolated and tested for lutein production. Chlorella sorokiniana Mb-1, with the highest lutein productivity, was chosen for further studies. The effects of acetate and nitrate concentrations in the BG11-based medium were examined. The optimum concentrations of nitrate and acetate were determined using a statistical experimental design methodology. The results show that the optimal composition of acetate and nitrate was 4.88 g/L and 1.83 g/L, respectively, leading to a predicted lutein productivity of 3.96 mg/L/day. This predicted value was verified by experiments indicating that lutein productivity could be enhanced from 2.79 mg/L/day to 3.97 mg/L/day (42% enhancement) via optimizing the carbon and nitrogen sources in the mixotrophic culture medium.