Effect of Different Carbon Sources on Biosynthesis of Exopolysaccharide from Antarctic Strain Cryptococcus Laurentii AL62

ABSTRACTIsolate AL62 isolated from Antarctic soil was identified as Cryptococcus laurentii AL62 based on its morphological, cultural and physiological properties and was selected as an active producer of exopolysaccharide. Different carbon sources (pentoses, hexoses and oligosaccharides) were investigated for biosynthesis of biopolymer and sucrose was chosen as the most suitable and available carbon source. The time course of exopolysaccharide synthesis, biomass and pH on different sucrose concentration (30, 40, 50 g/L) were studied. The heteropolysaccharide was composed of the following monosaccharides: xylose, 45.2%; mannose, 33.6%; glucose, 18.4%. It was characterized by polydispersity of the polymer molecule, 60% of it having molecular mass of 8000 Da.