photosynthesis and heterotrophic growth occur simultaneously and independently in mixotrophic cultures (Marquez et al.,1993), the presence of organic carbon can alter both the photosynthetic and heterotrophic metabolism of Chlorella (Villarejo et al.,1995). The lipid and biomass production of mixotrophic cultivation are much higher than under autotrophic and heterotrophic cultivation indicated in previous work (Table 1). Thus, these findings indicate that adding organic carbon sources leads to a marked stimulation of lipid accumulation in Chlorella sp. Y8-1, and that the ideal organic carbon source for the production of lipids is
sucrose.