Preparation and preliminary characterization of exopolysaccharides by yeast Rhodotorula acheniorum MC

The effects of various carbon and nitrogen sources on the synthesis of exop olysaccharides by Rhodotorula acheniorum MC were studied. The dynamic visco sity of cell-free culture broths during exopolysaccharide synthesis were me asured. The highest values for the viscosity (10.14 MPa.s) and crude polysa ccharide productivity (6.6 g/L) were obtained in a medium supplied with 5% sucrose. Ammonium sulfate was the mast favorable nitrogen source for exopol ysaccharide synthesis. The value of pH played a determinant role, and the o bligatory condition for exopolysaccharide production was low (pH 1.7-2.0) d uring the fermentation. The chemical composition and sugar constituents of the crude exopolysaccharides were determined. Mannose was the main monosacc haride component, and its concentration was the highest (69.13%) in the cru de exopolysaccharide synthesized in the medium that included 5% sucrose as a carbon source.