Molecular species composition of glycolipids from Sprirulina platensis

The different fractions of glycolipids were separated by HPLC column. Lipase XI from Rhizopus arrhizus was used to hydrolyze the fatty acids esterified in sn-1. The main fatty acids in MGDG and DGDG were C16:0, C18:2n-6, and C18:3n-6; those in SQDG were C16:0 and C18:2n-6 with a small amount of C18:3n-6. The molecular species analysis of the glycolipids showed that unsaturated fatty acids, such as C18:2n-6 and C18:3n-6, mainly occupied the sn-1 position, while saturated fatty acid C16:0 occupied the sn-2 position. MGDG contained 43.6% (18:3, 16:0), 13.9% (16:0, 16:0), 9.9% (18:2,16:0), and 8.9% (18:3, 16:1). DGDG contained 37.6% (18:3, 16:0), 8.7% (16:0, 16:0), and 8.7% (18:2, 16:0). Molecular species composition of SQDG differed from those of MGDG and DGDG, and it contained 52.5% (18:2, 16:0), 11.0% (16:0, 16:0), 7.1% (16:1, 16:0), and 7.7% (18:1, 16:0).