Carbohydrate composition and characterization of two unusual sugars from the blue green alga Spirulina platensis

Abstract

Spirulina platensis contains 13.6% carbohydrate, the sugar composition of which is comprised principally of glucose along with rhamnose, mannose, xylose, galactose and two unusual sugars. The latter were identified by a combination of GC-MS, NMR and de- O-methylation as 2- O-methyl- L-rhamnose and 3- O-methyl- L-rhamnose. Water-soluble polysaccharides were complex and heterogeneous, while the acid-soluble polysaccharide was a homogeneous glucan.