Enhancing production of lutein by a mixotrophic cultivation system using microalga Scenedesmus obliquus CWL-1

This work studies a series of strategies in the production of lutein by Scenedesmus obliquus CWL-1 under mixotrophic cultivation. Our experimental results revealed that the optimal conditions associated with light-related strategies were 12 h light period followed by a 12 h dark period and blue to red light under mixotrophic cultivation. Under such conditions, the biomass, lutein content and lutein productivity were maximized to 9.88 (g/L), 1.78 (mg/g) and 1.43 (mg/L/day), respectively. Moreover, the assimilation of 4.5 g/L of calcium nitrate into S. obliquus CWL-1 increased the maximal biomass (12.73 g/L) and the highest maximal lutein productivity (3.06 mg/L/day), while the assimilation of 1.5 g/L of calcium nitrate yielded the highest maximal lutein content of 2.45 mg/g. The highest maximal lutein productivity of 4.96 (mg/L/day) was obtained when fed-batch fermentation was conducted, and this value was approximately 11-folds that obtained using the batch system.