Effects of Stimulators on Lutein and Chlorophyll Biosyntheses in the Green Alga Chlorella pyrenoidosa Under Heterotrophic Conditions

In this study, the effects of some stimulators on lutein and chlorophyll biosyntheses in dark grown Chlorella pyrenoidosa were investigated. The aim of this study was to find out some stimulators that could effectively stimulate lutein and chlorophyll biosyntheses in C. pyrenoidosa in darkness. Vitamin A showed a profound effect in stimulating lutein biosynthesis, 70.9 % of increase of lutein content was observed when 4 mM vitamin A was supplemented in the culture. Similarly, chlorophyll biosynthesis was also improved by vitamin A. In addition, β-carotene and zeaxanthin also showed a positive effect on lutein accumulation in C. pyrenoidosa under heterotrophic conditions. The lutein content increased by 27.1 and 19.8 % when 0.1 mg/mL zeaxanthin and β-carotene were added into the culture, respectively. Besides, added zeaxanthin also significantly improved the lutein yield, by 45.4 %. In conclusion, lutein biosynthesis could be effectively stimulated by the selected stimulators in the green alga C. pyrenoidosa under heterotrophic conditions.