Overexpression of endogenous delta-6 fatty acid desaturase gene enhances eicosapentaenoic acid accumulation in Phaeodactylum tricornutum

The effect of overexpression of endogenous delta-6 fatty acid desaturase gene (ER6FAD) on eicosapentaenoic acid (EPA) production and total lipid content was investigated in Phaeodactylum tricornutum. All three randomly selected transformants exhibited significant increase (47.66%) in their EPA content, which reached up to 38.101 mg/g DW in algal strain D63. The total lipid content of all the three transformants was significantly higher (16.40-18.64%) than that of the wild-type strain. These findings suggested that the reaction catalyzed by ER6FAD is a limiting step for EPA biosynthesis, overexpression of endogenous ER6FAD gene is an effective method for improving EPA production in eukaryotic microalgae, and fatty acid metabolic pathway in microalgae can be genetically modified.