A Study of Actively Cellulolytic Rod-Shaped Bacteria of the Bovine Rumen

Abstract

Eight strains of these gram-, nonmotile bacteria found in large numbers in rumen contents were selected for study on the basis of variation in morphology, pigment production, and isolation from different animals fed different rations. Only glucose, celloblose, cellulose, and pectin were fermented by all strains. Large amounts of succinic and acetic acid were produced, and carbon dioxide was taken up, in the fermentation of cellulose. It was concluded that all strains belonged to one species, Bacteroides succinogenes Hungate. Studies on the growth requirements showed that bicarbonate is required and suggested that rumen fluid contains an unknown heat, acid, and alkali-stable factor that is not a common B vitamin, amino acid, peptlde purine, pyrimidine or mineral and was not detected in several materials used to grow nutritionally fastidious bacteria or in extracts from alfalfa meal or bovine feces.