Lipid content of microparticulate (1-->3)-beta-D-glucan isolated from Saccharomyces cerevisiae

The preparation of pharmaceutical grade (1-->3)-beta-D-glucans from Saccharomyces cerevisiae requires that the microparticulate glucans which are employed as the starting material for drug production be of the highest purity. Potential contaminants of the (1-->3)-beta-D-glucan isolation process are yeast cell wall lipids, which are frequently found in association with glucans. The lipid content of yeast-derived (1-->3)-beta-D-glucan during various stages of the isolation process by methyl esterification and total ion gas chromatography and mass spectrometry (GC-MS) was examined. Following sequential alkaline and acid hydrolyses, the total lipid content of (1-->3)-beta-D-glucan was 100.4 nmol/mg with 9-cis-C 18:1 fatty acid accounting for 45.3 nmol/mg glucan (45%). Following ethanol extraction of the (1-->3)-beta-D-glucan, lipid was not detected. Indeed, fatty acid methyl esters were not detectable by total ion GC-MS in all twelve samples investigated. These data demonstrate that the isolation process for yeast-derived (1-->3)-beta-D-glucan effectively reduces contamination by yeast cell wall lipids.