Effect of the concentration of sodium chloride in the medium on the relative proportions of poly- and oligo-saccharides excreted by Rhizobium meliloti strain YE-2SL.

Rhizobium meliloti mutant strains have been found which, in the presence of low concentrations of NaCl, produce a galactoglucan instead of the usual succinoglycan. When grown in a mannitol-glutamic acid-salts medium, the principal products secreted by R. meliloti YE-2S1 were comparable quantities of succinoglycan repeating-units and galactoglucan. As NaCl was added progressively to the culture medium, the repeating units nearly completely disappeared and the galactoglucan was gradually replaced by a succinoglycan.