Amino acids produced by bifidobacteria and some Clostridia.

A lot of 121 strains of bifidobacteria and 9 strains of clostridia were examined for their ability to release free amino acids in the culture broth. The bifidobacteria studied belong to 18 species or "homology group" and the clostridia to 8 species. The growth in a synthetic medium with ammonium salts as sole nitrogen source was also studied. All the clostridia and the majority of the bifidobacteria produce various amino acids. The possible ecological significance of these findings is suggested.