EXOPOLYSACCHARIDE PRODUCTION BY THE RHIZOBIUM-MELILOTI M5N1 CS STRAIN - LOCATION AND QUANTITATION OF THE SITES OF O-ACETYLATION

The mutant strain M5N1 CS of Rhizobium meliloti is able to produce, in a Rhizobium complete medium supplemented with fructose or sucrose (1% w/v), a partially acetylated homopolymer of glucuronic acid. During batch cultivation, the polysaccharide production is observed while the pH of the medium decreases slightly. The nature of the carbon source and the control of pH have no effect on the degree of acetylation of the polymer produced in the flasks. About 40% of glucuronic residues of the polymer are monoacelylated at C-3 or at C-2, C-3 substitution is about twice that of C-2 and remains constant during the fermentation.