ISOLATION AND FERMENTATION CHARACTERISTICS OF STRAINS OF BUTYRIVIBRIO FROM RUMINAL INGESTA

Abstract

Eleven strains of Butyrivibrio were isolated from the ingesta of the bovine rumen. These cultures represented 1/5 of all isolates at 1 x 10"[degree] dilutions. The fermentations carried on by these organisms were sensitive to the environmental changes tested. Higher concentrations of acids were produced under a CO2 atmosphere than under N. Relative and absolute concentrations of the fermentation acids shifted with pH. Addition of fermentation acids to buffered rumen fluid-glucose media indicated that these organisms actively convert acetate and possibly propionate to butyrate. In the absence of rumen fluid or acetic acid, all strains produced either formic or acetic acid. Two strains produced propionate at the expense of lactate.