title: Isolation and characterization of novel S-equol-producing bacteria from brines of stinky tofu, a traditional fermented soy food in Taiwan.
abstract: Six strains capable of transforming daidzein to S-equol were isolated from the fermented brines of stinky tofu purchased in Taiwan. Daidzein was completely converted into S-equol within 24h of incubation in five strains. All the strains were gram-positive, rod-shaped, obligately anaerobic, non-motile, and non-spore-forming. In a phylogenetic analysis based on 16S rRNA gene sequences, the strains distributed into three groups in the family Coriobacteriaceae. SNR40-432 (Group I) showed 98.6% 16S rRNA gene similarity and 48-49% DNA-DNA relatedness with Paraeggerthella hongkongensis HKU10(T), suggesting the possibility that SNR40-432 represents a new species in the genus Paraeggerthella. SNR48-44 (Group II) and SNR44-10, SNR45-571, SNR46-41, SNR48-350 (Group III) showed a maximum of 92.2 and 92.1% 16S rRNA gene similarities with Eggerthella sinensis HKU14(T) and Eggerthella lenta JCM9979(T), respectively, which denotes that each group may represent a novel genus and species in the family Coriobacteriaceae. This is the first report isolating equol-producing bacteria from food.
authors.affiliation: Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical Co., Ltd , Saga , Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Abiru
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ueno
authors.forename: Shigeto
authors.initials: S
authors.lastname: Uchiyama
mesh_terms: D039903:Actinobacteria / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial; D004032:Diet; D060754:Equol / Q000378:metabolism*; D005285:Fermentation; D005516:Food Microbiology; D006801:Humans; D007529:Isoflavones / Q000378:metabolism; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D012492:Salts; D045730:Soy Foods / Q000382:microbiology*; D013025:Glycine max / Q000378:metabolism* / Q000382:microbiology; D013624:Taiwan
chemical_list: D004269:DNA, Bacterial; D007529:Isoflavones; D012336:RNA, Ribosomal, 16S; D012492:Salts; C017082:brine; D060754:Equol; C004742:daidzein