CYCLIC (1-]2)-BETA-D-GLUCANS EXCRETED BY THE GLUCURONAN-PRODUCING STRAIN RHIZOBIUM-MELILOTI M5N1CS (NCIMB-40472) AND BY THE SUCCINOGLYCAN-PRODUCING STRAIN RHIZOBIUM-MELILOTI M5N1

During fermentation, the mutant strain Rhizobium meliloti M5N1CS, whic h induces nodule formation on alfalfa roots, produces a partially acet ylated (1-->4)-beta-D-glucuronan. In addition to this exopolysaccharid e of high molecular weight, the mutant strain produces oligoglucoronat es and cyclic (1-->2)-beta-D-glucans with degrees of polymerization fr om 17 to 30. Under the conditions applied, magnesium has no effect on cyclic glucan production by the mutant strain, but the succinoglycan p roduction by the wild-type strain Rhizobium meliloti M5N1 increases.