Light irradiance modifies the fatty acid composition of Amphidinium carterae (Dinophyceae)

Abstract

ABSTRACT Amphidinium carterae is a dinoflagellate of increasing interest for producing bioactive compounds. The aim of this study was to investigate the effect of five irradiances (50, 100, 150, 200 and 250 µmol photon m–2 s–1) on the fatty acid profile of A. carterae. The results show that high irradiances increase the lipid productivity (36.65 mg l–1 d–1 at 50 µmol photon m–2 s–1 to 90 mg l–1 d–1 at 250 µmol photon m–2 s–1). High irradiance increased the content of polyunsaturated fatty acids (PUFAs) relative to the total content of fatty acids (40.0% at 50 µmol photon m–2 s–1 to 53.23% at 250 µmol photon m–2 s–1) and decreased the amount of monounsaturated fatty acids (MUFAs) (14.30% at 50 µmol photon m–2 s–1 to 6.04% at 250 µmol photon m–2 s–1). The higher PUFAs content was due to docosahexaenoic acid (DHA; 20.76% at 50 µmol photon m–2 s–1 to 30.63% at 250 µmol photon m–2 s–1) and eicosapentaenoic acid (EPA; 14.91% at 50 µmol photon m–2 s–1 to 18.96% at 250 µmol photon m–2 s–1). Palmitic acid (C16:0) had the highest content among saturated fatty acids (19.87% at 50 µmol photon m–2 s–1 to 22.29% at 250 µmol photon m–2 s–1). The proportion of neutral lipids tended to increase under high irradiances (100–250 µmol photon m–2 s–1). At the lowest irradiance (50 µmol photon m–2 s–1), the proportion of polar lipids was higher than that of neutral lipids. PUFAs had the main content within polar lipids at the five irradiances (47%–50%). The major neutral lipids were SFAs at the five irradiances (47%–51%). It was concluded that the irradiance levels influence the lipid metabolism of A. carterae. The increase in irradiance level raises the production of lipids and the content of EPA and DHA for potential utilization in the biotechnological, aquaculture and nutraceutical industries.