Studies on structural and physical characteristics of a novel exopolysaccharide from Pseudozyma sp. NII 08165.

The aim of this work was to study the production of exopolysaccharide (EPS) from a novel ustilaginomycetes yeast strain Pseudozyma sp. NII 08165. The culture produced 3.5g/l EPS on fourth day of fermentation in a glucose-based medium. The structural characterization revealed that the EPS was a polymer of glucose, galactose and mannose in the ratio of 2.4:5.0:2.6 with a molecular weight of 1.7MDa. The pseudoplastic behaviour of aqueous EPS with a thermal stability up to 220°C indicated its potential utility as a thickening or gelling agent in food industry. SEM studies of the EPS showed that it had compact film-like structure, which could make it a useful in preparing plasticized films. The AFM studies showed that EPS had spike-shaped microstructure. Physical properties of the exopolysaccharide determined further indicated its possible potential in different industrial applications.