Effect of temperature on the growth and fatty acid composition of Phaeodactylum tricornutum

Analysis of fatty acids of Phaeodactylum tricornutum at different growth phases(the exponential,the end of exponential,the stationary,and the degradation phase)indicated that the percentage of eicosapentaenoic acid(EPA)in total fatty acids peaked at the end of the exponential growth phase.The gene expression pattern of Δ5 desaturase at different growth phases of P.tricornutum was analyzed by real-time quantitative PCR.The results showed that it was most highly expressed at the exponential growth phase.In order to study the effect of temperature on the growth and fatty acid composition in the microalgae,P.tricornutum was cultured in batch at varied temperatures.It was found that the algae grew faster at higher temperatures;the higher the temperature,the greater the growth rate.The main fatty acids were C14∶0,C16∶0,C16∶lΔ9,Cl8∶lΔ9,C18∶2Δ9,12,and C20∶5n3(EPA).As the temperature increased,the percentage of fatty acids increased first and then decreased.Microalgal cell which was cultured at 15℃ had the highest content of EPA(25.71%).