Factors necessary for the growth of Bacteroides succinogenes in the volatile acid fraction of rumen fluid.

Abstract

Summary Factors necessary for the growth of Bacteroides succinogenes and present in the volatile acid fraction of rumen fluid have been identified. Any one of the branched-chain saturated acids, isobutyric, isovaleric, or dl-α-methyl- n -butyric acid can be used as one component. Any one of a number of straight-chain saturated fatty acids can be used as the second component. These include C 5 to C 8 acids. Some activity for the second component was found in stearic and palmitic acid but none in lauric acid. Minimum concentrations for good growth when n -valeric and isovaleric acids were used were about 3 and 1.5 μM, respectively, per 10ml. of medium. All available strains of Bact. succinogenes require these acids. After this work was submitted for publication, Bentley et al. reported that the volatile acids, n -valeric, isovaleric, isobutyric, and caproic, or their amino acid precursors, stimulated cellulose digestion and the conversion of urea nitrogen into protein by rumen microorganisms as measured by the artificial rumen technique (J. Am. Chem. Soc., 76: 5000. 1954).