SOME FERMENTATION CHARACTERISTICS OF VARIOUS STRAINS OF RHIZOBIUM MELILOTI AND RHIZOBIUM JAPONICUM

Publisher Website
Google Scholar
Abstract
Twenty-three strains of Rhizobium meliloti and 12 of R. japonicum were studied to ascertain the constancy of their fermentative characteristics and also the extent of the fermentative variations among individual strains of the same species. They were grown in yeast-water-glucose and yeast-water-galactose media in 5 or more consecutive tests. The change in pH in the media was taken as a measure of fermentative ability. Results indicate that the fermentative powers of individual strains were approximately the same in the various consecutive tests, and that the fermentative ability of a particular strain is a comparatively constant character. The data also indicate clearly that there are large variations in fermentation characters of different strains of the same species. Some of the meliloti strains produced a distinctly alkaline reaction and others produced a strongly acid reaction in media of the same composition. Some strains made the media 100 times as acid as other strains of the same species. Some of the japonicum strains produced a very slightly alkaline reaction in the media; others produced a reaction almost 10 times as alkaline. The strains of R. meliloti fermented glucose and galactose with about the same comparative results. On the other hand, the strains of R. japonicum did not appear to ferment these 2 sugars in the same manner. The majority of the japonicum strains produced a much more alkaline reaction than the majority of the meliloti strains, but this difference was not true for all individual strains. Results indicate that the fermentation test with glucose and galactose and under conditions similar to those here followed would not serve to give a distinct separation of organisms of these 2 species of legume bacteria.

This publication has 2 references indexed in Scilit: