PRODUCTION OF POLYSACCHARIDE S-7

摘要

Modified derivatives of the naturally occurring parental bacterium Sphingomonas strain S-7 were constructed by genetic engineering. The new strains exhibit increased conversion of the carbon source in a nutrient culture medium into the product exopolysaccharide S-7, compared to the unmodified parent strain. A polysaccharide was prepared from one of the genetically-modified derivatives. The polysaccharide has a carbohydrate composition which is different from the parent polysaccharide S-7, and which confers increased viscosity on the polymer while in the fermentation broth or after isolation of the polymer. The polysaccharide is useful to modify the viscosity of aqueous solutions, and demonstrates increased viscosity at lower concentrations.