Genomics and physiology of , human gut bacteria capable of polyphenol -deglycosylation and flavonoid degradation.

The genus (family , phylum ) includes only one cultivated species so far, isolated from human faeces and capable of deglycosylating dietary polyphenols and degrading flavonoid aglycones. Another human intestinal strain not taxonomically resolved at that time was recently genome-sequenced. We analysed the genome of this novel isolate, designated , and showed its ability to deglycosylate -coupled flavone and xanthone glucosides and -coupled flavonoid glycosides. Most of the resulting aglycones were further degraded to the corresponding phenolic acids. Including the recently sequenced genome of and ten faecal metagenome-assembled genomes assigned to the genus , we performed a comparative genome analysis and searched for genes encoding potential -glycosidases and other polyphenol-converting enzymes. According to genome data and physiological characterization, the core metabolism of strains is based on a fermentative lifestyle with butyrate production and hydrogen evolution. Both and encode a flavonoid -glycosidase, a flavone reductase, a flavanone/flavanonol-cleaving reductase and a phloretin hydrolase. Several gene clusters encode enzymes similar to those of the flavonoid -deglycosylation system of strain PUE (DgpBC), while separately located genes encode putative polyphenol-glucoside oxidases (DgpA) required for -deglycosylation. The diversity of and gene clusters might explain the broad -glycoside substrate spectrum of and . The other genomes encode only a few potential flavonoid-converting enzymes. Our results indicate that several species are well-equipped to deglycosylate and degrade dietary plant polyphenols and might inhabit a corresponding, specific niche in the gut.