Effect of nutrient condition on the growth of Chlorella vulgaris

Effect of culture medium and organic carbon source to growth of Chlorella vulgaris were investigated. The results show that both the cell density and the specific growth rate of mixtrophic algae were the largest in three metabolic pathways, either the cell density or the specific growth rate was larger than the sum of autotrophic and heterotrophic. When mixtrophic C. vulgaris was cultured using different organic carbon source, the maximal cell density was 2.92 g/L (glucose), 1.62 g/L (sodium acetate) and 1.05 g/L (alcohol), respectively. In addition, the specific growth rate reached the largest when glucose was used. However, the specific growth rate of C. vulgaris decreased from 0.0248 h^-1 to 0.0186 h^-1 as the concentration of glucose increased from 5 to 30 g/L. It was found that the cell density at 10 g/L glucose exceeded 5 g/L glucose at stable period of growth. The maximal cell density and specific growth rate of C. vulgaris were achieved when the BG11 medium was used and 10 g/L glucose added. It was 3.41 g/L and 0.0257 ^-1, respectively. When the Basal medium was used, the cells of algae were suspended over the culture period. Then the cell density and specific growth rate was 3.25 g/L and 0.0204 h^-1, respectively.