CHARACTERISTICS OF A NOVEL HIGH-VISCOSITY POLYSACCHARIDE, METHYLAN, PRODUCED BY METHYLOBACTERIUM-ORGANOPHILUM

A new anionic high molecular weight polysaccharide, Methylan, was produced by Methylobacterium organophilum from methanol as a sole source of carbon and energy under the specific culture conditions. By GPC and light scattering, the molecular weight was determined to be 2-4 x 10(6) dalton and the distribution of molecular weight was very homogeneous. Methylan was composed of carbohydrate (80%), uronic acid (12%), protein (6%) and pyruvic acid (5%). The sugar composition of Methylan was identified as glucose, galactose and mannose with the approximate molar ratio of 2:3:2. Methylan solution showed a pseudoplastic non-Newtonian fluid property at the concentration above 0.05%. At the concentration of 1% Methylan solution, the consistency index was 18,000 centipoise which was almost 10 times higher than that of Xanthan and the flow behavior index was 0.15.