Effect of nitrogen concentrations on growth and protein content of heterotrophic microalgae

In order to improve the problem of low protein content of heterotrophic Chlorella vulgaris,the effects of nitrogen concentrations on growth and protein content of Chlorella vulgaris were studied.The regulations of nitrogen concentrations in different phases on the growth and protein content of Chlorella vulgaris were also studied.The results showed that protein content of Chlorella vulgaris was increased from 26.1% to 37.4% with the increase of initial nitrogen concentration from 12 to 15mmol/L.The control strategy was that firstly let Chlorella vulgaris grow under low nitrogen concentration to its exponential phase,and then transfered it to high nitrogen concentration.So we could obtaine both high biomass 3.04g/L and high protein content of 53.8%,which reaches the protein level of Chlorella vulgaris in autotrophic culture.