sp. nov., an equol non-producing bacterium isolated from human faeces.

Two obligately anaerobic, Gram-stain-positive, rod-shaped bacteria were isolated from faecal samples of healthy humans in Japan. 16S rRNA gene sequence analysis indicated that these two strains (8CFCBH1 and 9CBH6) belonged to the genus , which is known as an equol-producing bacterium. The closest neighbours of strain 8CFCBH1 were subsp. DSM 19450 (98.6%), subsp. do03 (98.4%), WCA-131-CoC-2 (96.6%), NR06 (96.4%), B7 (95.3%) and Mt1B8 (95.3%). The closest relatives to strain 9CBH6 were subsp. DSM 19450 (99.8%), subsp. do03 (99.6%) and WCA-131-CoC-2 (96.8%). Strain 8CFCBH1 showed 22.3-53.5% digital DNA-DNA hybridization (dDDH) values with its related species. In addition, the average nucleotide identity (ANI) values between strain 8CFCBH1 and its related species ranged from 75.4 to 93.3%. On the other hand, strain 9CBH6 was considered as based on the dDDH and ANI values (>70% dDDH and >95-96% ANI). Strain 9CBH6 showed daidzein-converting activity, as expected from the result of genome analysis. The genome of strain 8CFCBH1 lacked four genes involved in equol production. Growing cells of strain 8CFCBH1 were not capable of converting daidzein. Based on the collected data, strain 8CFCBH1 represents a novel species in the genus , for which the name sp. nov. is proposed. The type strain of is 8CFCBH1 (=JCM 34083=DSM 112284).