Mercury Methylation by Interspecies Hydrogen and Acetate Transfer between Sulfidogens and Methanogens

Cocultures of Desulfovibrio desulfuricans and Methanococcus maripaludis grew on sulfate-free lactate medium while vigorously methylating Hg(2+). Individually, neither bacterium could grow or methylate mercury in this medium. Similar synergistic growth of sulfidogens and methanogens may create favorable conditions for Hg(2+) methylation in low-sulfate anoxic freshwater sediments.