ALTERATIONS IN LIPID MOLECULAR-SPECIES OF THE MARINE EUSTIGMATOPHYTE NANNOCHLOROPSIS SP

The molecular species of triacylglycerol and monogalactosyl diacylglyc erol from the marine eustigmatophyte Nannochloropsis were analyzed by high-performance liquid chromatography with a flame ionizationn detect or. Four major molecular species of triacylglycerol composed of C14:0, C16:0, and C16:1 fatty acids at different combinations were identifie d. Six molecular species of mono-galactosyl diacylglycerol were detect ed. Three of them contained C20:5 fatty acid in the sn-1 position, and one component accommodated C20:5 fatty acid in both the sn-1 and sn-2 positions. Variations in the relative distribution of the molecular s pecies were further monitored in Nannochloropsis cultures grown under different irradiance levels and temperatures. The relative distributio n of 16:0/16:1/16:0 triacylglycerol increased in cells grown in high l ight and in high temperature. Variations in cellular fatty acid compos ition in Nannochloropsis grown under different environmental condition s of irradiance level and temperature were attributed to alterations i n relative cellular content of lipid classes as well as in the relativ e composition of lipid class molecular species.