Detoxification of ammonium to Nannochloropsis oculata and enhancement of lipid production by mixotrophic growth with acetate

In this study, the toxicity of ammonium was removed in the microalga Nannochloropsis oculata by using acetate as a carbon source. Algal biomass and lipid production were significantly enhanced when N. oculata was grew on 0.5-50 mM of ammonium and 16-64 mM of acetate in mixotrophic conditions. When grown mixotrophically on 1 mM of ammonium and 32 mM of acetate, the biomass and lipid production reached 543 mg/L and 279 mg/L respectively, which were 1.5 and 9.4 times higher than the levels generated when grown autotrophically on nitrate. This suggests that mixotrophic growth with acetate can be a useful method to enhance microalgal lipid production.