Fig. 1
Potential microbial sulfur transformations in the human gut microbiome. Microbial sulfur metabolism results in the production of genotoxic H2S (dashed box) via metabolism of inorganic sulfate (yellow) or organic sulfur amino acids like cysteine and methionine (maroon), or taurine (orange). Previous studies of microbial sulfidogenesis in the human gut have focused mainly on genes harbored by Bilophila, Fusobacterium, and the sulfate-reducing bacteria (bolded with a “caret”). All genes listed were analyzed in this study except those listed in gray. Reactions are not balanced and only the main sulfur component reactants and products are shown. Some intermediate steps are not shown