Chemoplasticity of the polar lipid profile of the microalgae Chlorella vulgaris grown under heterotrophic and autotrophic conditions

Chlorella growing under different conditions can adapt its biochemical composition and its fatty acid profile, but the alterations in polar lipids remain poorly explored. In this study, the polar lipidome of Chlorella vulgaris grown under autotmphic (C-Auto) and heterotrophic (C-Hetem) conditions were characterized using hydrophilic interaction liquid chromatography-electmspray ionization mass spectrometry and gas chromatography-mass spectrometry. A total of 173 and 167 lipid species were identified in autotmphic and heterotrophic cultures, respectively, distributed by lyso and phosphatidylcholine, lyso and phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, sulfoquinovosyldiacylglyceml, di- and monogalactosyldiacylglycerol, di- and monogalactosylmonoacylglyceml, ceramide, and inositolphosphoceramide lipid classes. C-Hetero had a higher abundance of low unsaturated species, while C-Auto had a high abundance of highly unsaturated glycolipids and lyso species. The fatty acids profile showed a high content of omega-3 polyunsaturated fatty acids in C-Auto and in omega-6 fatty acids in C-Hetem. The two lipid extracts showed high antioxidant activity and inhibitory capacity for cyclooxygenase-2. This study provides evidence of polar lipid plasticity of microalgae useful for tuning cultivation for biotechnology applications.

Automated summary

This study characterized the polar lipidome of Chlorella vulgaris grown under autotrophic and heterotrophic conditions, revealing differences in lipid species and abundance distribution. Heterotrophic cultures had a higher abundance of low unsaturated species, while autotrophic cultures were rich in highly unsaturated glycolipids and lyso species. The fatty acids profile showed a high content of omega-3 polyunsaturated fatty acids in autotrophic cultures and omega-6 fatty acids in heterotrophic cultures. The two lipid extracts exhibited high antioxidant activity and inhibitory capacity for cyclooxygenase-2, providing evidence of polar lipid plasticity in microalgae for biotechnology applications.