NOVEL POLYSACCHARIDE HAVING SPECIFIC VISCOSITY CHARACTERISTIC AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain a polysaccharide which has a specified molecular weight and constituents and, upon a change in a concentration, not only changes in its viscosity but also changes in its state from a viscous solution to a gel state by culturing bacteria of the genus Pseudomonas in a nutrient medium and recovering it from the culture. SOLUTION: Polysaccharide-producing bacteria of the genus Pseudomonas are cultured in a nutrient medium, and the polysaccharide is collected from the culture. The bacteria cultured may be those of any species and strain so far as they belong to the genus Pseudomonas and produce a polysaccharide. The polysaccharide produced by this method has a molecular weight of about 1,600,000 when determined by high-performance liquid chromatography using a gel filtration column and has constituents comprising glucose residues and mannose residues in a 1:1 molar ratio. A 0.5w/v% aqueous solution of this polysaccharide is a viscous solution at a temp of 5-10 deg.C, whereas its 1w/v% aqueous solution is in a gel state.