Lipid and lipopolysaccharide constituents of cyanobacterium Spirulina platensis (Cyanophyceae, Nostocales)

Abstract

The nature and quantity of lipids and lipopolysaccharides of S. platensis were examined. Organic cell weight consisted of 50% protein, 8.8% carbohydrate and 16.6% lipids. Carotenoid-to-chlorophyll ratio was 0.3. Lipids consisted of a diverse assortment of pigments, hydrocarbons, glycolipids, and phosphatidyl glycerol. Fatty acid contents were predominantly even-numbered chains with a relatively high proportion of polyunsaturated fatty acids. Lipopolysaccharide consisted of unsaturated fatty acids, 3-hydroxy myristate and the carbohydrates, hexoses, heptose, octulosonic acid and glucosamine. Assays of the lipopolysaccharide preparation by the Limulus amoebocyte lysate test and by the lethal toxicity test in mice demonstrated that the lipoplysaccharide of S. platensis is toxic but its toxicity is in the order of 10% of the lipopolysaccharide fraction of Salmonella abortus.