A Bacterial Pathway for Homotaurine Catabolism via Sulfopropanoate

Homotaurine, a C₃-aminoorganosulfonate produced by marine algae and present in algal-derived foods, is comparatively well documented, but its complete microbial catabolism has remained unresolved. Here we identify a complete bacterial pathway for homotaurine catabolism in Caballeronia jiangsuensis strain McCoy, isolated by metabolic enrichment from soil by growth on homotaurine.

Growth, proteomic, metabolomic, biochemical, structural, and heterologous-expression analyses show that homotaurine is imported and oxidatively deaminated to sulfopropanoate, then converted to sulfolactate through <i>E</i>-sulfoacrylate by SpuABCD and SpuIJ, enzymes related to succinate dehydrogenase and fumarase. Sulfolactate is cleaved by redundant SuyAB sulfolyases to release pyruvate and sulfite, which is oxidized and excreted as sulfate, completing biomineralization.