Selective isolation and characteristics of Bacteriodes succinogenes from the rumen of a cow

Eleven isolates of Bacteriodes succinogenes were obtained from the rumen of a cow by an enrichment method with dewaxed cotton fibers as the selective substrate. All of the isolates degraded cotton fibers, but none formed clear zones in cellulose agar, having only a limited ability to degrade the type of cellulose powder used. One isolate, BL2, was studied in greater detail and was found to accumulate a glycogen-like polysaccharide when excess (0.5 to 1.0%) soluble carbohydrate was supplied in the nutrient medium. Although the pattern of growth and polysaccharide accumulation by strain BL2 changed during maintenance of the organism in the laboratory, the maximum amount of carbohydrate found in the cells was constant, at around 74% of the cell dry weight. The findings are discussed in relation to the methods of assessing the role of B. succinogenes in the rumen fermentation.