Effects of different abiotic stresses on carotenoid and fatty acid metabolism in the green microalga Dunaliella salina Y6

Abstract Purpose Under different abiotic-stress conditions, the unicellular green microalga Dunaliella salina accumulates large amounts of carotenoids which are accompanied by fatty acid biosynthesis. Carotenoids and fatty acids both possess long carbon backbones; however, the relationship between carotenoid and fatty acid metabolism is controversial and remains poorly understood in microalgae. Methods In this study, we investigated the growth curves and the β-carotene, lutein, lipid, and fatty acid contents of D. salina Y6 grown under different abiotic-stress conditions, including high light, nitrogen depletion, and high salinity. Results Both high-salinity and nitrogen-depleted conditions significantly inhibited cell growth. Nitrogen depletion significantly induced β-carotene accumulation, whereas lutein production was promoted by high light. The accumulation of lipids did not directly positive correlate with β-carotene and lutein accumulation under the three tested abiotic-stress conditions, and levels of only a few fatty acids were increased under specific conditions. Conclusion Our data indicate that cellular β-carotene accumulation in D. salina Y6 positive correlates with accumulation of specific fatty acids (C16:0, C18:3n3, C14:0, and C15:0) rather than with total fatty acid content under different abiotic stress conditions