Effect of NaNO_3 Concentrations on the Growth and Fatty Acid Compositions of Nitzschia closterium and Chaetoceros gracilis*

摘要

Fatty acid compositions of two strains of marine diatoms Nitzschia closterium ( MACC B222 ) and Chaetoceros gracilis ( MACC B13 ) have been examined. The microalgae have been grown at different initial NaNO3 concentrations (75,375, 750, 1125,1 500, 1 875 mg/L ) and harvested at the late exponential phase. The results by one factor analysis of variance show that the NaNO3 concentrations have no significant influence on the relative growth rate of two strains of marine diatoms; the influence of NaNO3 concentrations on the fatty acids differs from species to species. The major fatty acids of two diatom strains are 14:0, 16:0, 16:ln- 7 and 20:5n- 3 ( EPA ) , B13 also has high percentage of20:4n-6 (6.0～9.1%).