Identification and functional characterisation of genes encoding the omega-3 polyunsaturated fatty acid biosynthetic pathway from the coccolithophore Emiliania huxleyi

► Emiliania huxleyi synthesises eicosapentaenoic acid via the alternative pathway. ► E. huxleyi Δ5-desaturase is an acyl-CoA-dependent enzyme. ► Although octadecapentaenoic acid is the most abundant fatty acid in E. huxleyi, it is absent from the acyl-CoA pool.