title: Methane oxidation and its coupled electron-sink reactions in ruminal fluid.
abstract: OBJECTIVE
  This study was conducted to investigate the occurrence of methane oxidation in the rumen, and to identify the electron-sink reaction coupled to the oxidation if it occurred.
  
  
  RESULTS
  Mixed ruminal microbes taken from sheep were incubated with 13CH4. Oxidation of methane, estimated from the flux of 13C to CO2 and microbial cells, occurred, but represented only 0.2-0.5% of the methane produced. Methane oxidation was suppressed by the presence of oxygen, and was also inhibited by 2-bromoethane-sulphonate, and molybdate, but not by tungstate.
  
  
  CONCLUSIONS
  Methane could be oxidized anaerobically in the rumen by reverse methanogenesis in consort with sulphate reduction.
authors.affiliation: National Institute of Livestock and Grassland Science, Tsukuba Norindanchi, Ibaraki, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kajikawa
authors.forename: C
authors.initials: C
authors.lastname: Valdes
authors.forename: K
authors.initials: K
authors.lastname: Hillman
authors.forename: R J
authors.initials: RJ
authors.lastname: Wallace
authors.forename: C
authors.initials: C
authors.lastname: J  Newbold
mesh_terms: D000818:Animals; D001419:Bacteria / Q000378:metabolism; D004583:Electrons; D008697:Methane / Q000378:metabolism*; D009566:Nitrates / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology; D012417:Rumen / Q000378:metabolism* / Q000382:microbiology*; D012756:Sheep; D013431:Sulfates / Q000378:metabolism
chemical_list: D009566:Nitrates; D013431:Sulfates; D008697:Methane; D010100:Oxygen