title: Origin of hydrogen in methane produced by Methanobacterium thermoautotrophicum.
abstract: The production of deuterated methane by Methanobacterium thermoautotrophicum in H2O-D2O mixtures was examined by high-resolution mass spectrometry. The hydrogen in the methane arose solely from water and not from hydrogen gas. Hydrogen gas served only as an electron source in methanogenesis. A whole-cell product isotope discrimination of 1.5 favoring hydrogen over deuterium was observed in methane production in 81 atom% deuterated water. The distribution of deuterated methane species is described by a simple model of the overall reaction.
mesh_terms: D003903:Deuterium / Q000378:metabolism; D019605:Euryarchaeota / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism*; D013058:Mass Spectrometry; D008697:Methane / Q000096:biosynthesis*; D008956:Models, Chemical; D014867:Water / Q000378:metabolism
chemical_list: D014867:Water; D006859:Hydrogen; D003903:Deuterium; D008697:Methane