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 Chlorella vulgaris. 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, Chlorella vulgaris 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 Chlorella vulgaris.