Regulation of biomass, pigments, and lipid production byChlorella vulgaris31 through controlling trophic modes and carbon sources

The effects of various carbon sources on growth, photosynthetic pigments and lipid production ofChlorella vulgaris31 were investigated under photoautotrophic, mixotrophic and heterotrophic cultivations. The results indicated that in two concentration gradients (2 and 10 g L-1), glucose, maltose and sodium acetate all significantly promoted the growth ofC. vulgaris31, while the effects of sucrose and glycerol were not significant. The alga could barely assimilate xylose. The biosynthesis of chlorophylls and carotenoids in algal cells was reduced under mixotrophic and heterotrophic cultivations; however, lipid production was promoted significantly. Moreover, this inhibition or promotion has significant concentration dependence of carbon source. The composition and proportion of fatty acids could also be regulated by different culture conditions and organic carbon sources. The finding suggests that the biomass, pigment and lipid production ofC. vulgaris31 could be regulated by controlling the trophic mode and carbon source.