Intestinal Bacterium TM-30: an S-equol-producing Bacterium Isolated from Human Feces is Involved in Estrogen Metabolism in vitro

A rod-shaped and Gram-positive anaerobic S-equol-producing intestinal bacterium, TM-30, was isolated from the feces of a healthy human. The 16S rRNA partial sequence of strain TM-30 exhibited 99% identity to that of Slackia sp. NATTS. TM-30 produced S-equol from daidzein. The in vitro incubation of beta-estradiol with TM-30 yielded estrone, and incubation of estrone with TM-30 produced beta-estradiol. The estrone producing activity was higher than the beta-estradiol producing activity. The results presented herein demonstrate that the S-equol-producing human intestinal bacterium, TM-30, likely plays a role in estrone and beta-estradiol metabolism in vitro.