Methane oxidation by Nitrosomonas europaea.
Methane inhibited NH4+ utilization by Nitrosomonas europaea with a Ki of 2mM. O2 consumption was not inhibited. In the absence of NH4+, or with hydrazine as reductant, methane caused nearly a doubling in the rate of O2 uptake. The stimulation was abolished by allylthiourea, a sensitive inhibitor of the oxidation of NH4+. Analysis revealed that methanol was being formed in these experiments, with yields approaching 1 mol of methanol per mol of O2 consumed under certain conditions. When cells were incubated with NH4+ under an atmosphere of 50% methane, 50 microM-methanol was generated in 1 h. It is concluded that methane is an alternative substrate for the NH3-oxidizing enzyme (ammonia mono-oxygenase),m albeit with a much lower affinity than for methane mono-oxygenase of methanotrophs.
D000645:Ammonium Sulfate / Q000378:metabolism; D007700:Kinetics; D008697:Methane / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D009606:Nitrosomonas / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D010101:Oxygen Consumption
D010088:Oxidoreductases; C045582:ammonia monooxygenase; D008697:Methane; D000645:Ammonium Sulfate; D000432:Methanol