CHARACTERISTICS OF RUMINAL ANAEROBIC CELLULOLYTIC COCCI ANDCILLOBACTERIUM CELLULOSOLVENSN. SP

Abstract

Twenty-eight strains of cellulolytic cocci isolated from rumen contents of 5 cows fed 5 rations were studied. Variation in many characteristics between strains did not correlate so that strains could be separated into well defined species. However, when fermentation products in cellobiose medium were determined on 14 representative strains, 12 cultures were placed in 2 groups. Five strains, placed in the species Ruminococcus flavefaciens Sijpesteijn, formed long chains and produced mainly succinic, acetic, and formic acids. Seven strains, placed in the species R. albus Hungate, usually occurred as singles and diplococci and produced mainly ethanol, acetic and formic acids, and, usually, gas that included hydrogen. The 2 remaining strains produced a large amount of lactic acid and did not fit well into either species. There seemed to be no correlation between characteristics of ruminococci isolated and the sample of rumen contents from which they were obtained. Most strains fermented xylan: this indicates another important function of ruminococci in the rumen. Cillobacterium cellulpsplvensn. sp. is a species of anaerobic, cellulolytic, gram-positive, peritrichous rod with pointed ends that produces predominantly lactic acid in cellobiose medium. It seems to be relatively unimportant in the rumen under conditions so far studied.