Observations on the Nutrition of Bacteroides Succinogenes—A Ruminal Cellulolytic Bacterium

Abstract

Studies on 5 strains indicated that biotin was essential for growth of 4 and highly stimulatory for the other. p-Aminobenzoic acid stimulated growth of 2 strains. No other vitamins had an effect on growth. Ammonia was essential for growth in the presence of 19 amino acids, a mixture of purines and pyrimidines, and all B-vitamins. None of the amino acids were essential for growth and good, but somewhat delayed, growth was obtained when cysteine or glutathione were the only sources of amino acids avialable. Studies on strain S85 showed that cysteine or sulfide could serve as the sole source of S. The essentiality of PO4---, NH4+, Mg++, Ca++, K+, and Na+ was demonstrated and the levels required were established. Although glucose was used as energy source in most experiments, it was demonstrated that good growth and cellulose digestion occurred in a medium containing only cellulose, p-aminobenzoic acid, biotin, cysteine, alanine, phenylalanine, valerate, isobutyrate, carbonic acid -bicarbonate buffer, resazurin and minerals. The results indicate the great ability of B. succinogenes to synthesize cellular constituents and show how well this bacterium is adapted to the ruminal environment.