Optimizing Chlorella vulgaris Cultivation to Enhance Biomass and Lutein Production

Lutein is widely used in medicine, health care, and food processing due to its antioxidant effects; however, it is difficult for the traditional extraction of lutein using marigolds to meet the increasing market demand for lutein. To achieve high-efficiency lutein production, we investigated the effects of different conditions on the biomass accumulation and lutein yield of <i>Chlorella vulgaris</i>. The optimized cultivation conditions include mixotrophic cultivation using sodium nitrate as a nitrogen source, maintaining a total-organic-carbon-to-total-nitrogen ratio of 12:1, a total-nitrogen-to-total-phosphorus ratio of 10:1, and lighting duration of 24 h. The results of the study indicated that under these specific conditions, <i>Chlorella vulgaris</i> attained a final biomass concentration, biomass productivity, and growth yield of 6.08 g·L^-1, 1.00 g·L^-1·d^-1, and 1.67 g biomass/g TOC, respectively. Additionally, the concentrations of total chlorophyll, carotenoid, lutein, and protein reached 139.20 mg·L^-1, 31.87 mg·L^-1, 15.02 mg·L^-1, and 2.17 g·L^-1, respectively, and the content of lutein reached 2.47 mg·g^-1. This study supplies a theoretical basis for the industrial application of lutein production using <i>Chlorella vulgaris</i>.