Catalysis and regulation in the soluble methane monooxygenase system: Applications of isotopes and isotope effects

Methanotrophic bacteria exist by using methane as a sole source of carbon and energy.1,2 They are typically found in lakes, oceans, and wetlands at the interface between the anaerobic and aerobic environments. At this boundary, they can use O₂ from atmospheric mixing or photosynthesis to initiate the oxidation of methane released by anaerobic methanogenic organisms as a consequence of their metabolism. Since methanotrophic bacteria are the only aerobic organisms that efficiently oxidize methane, they play a major role in restricting the egress of methane, a powerful greenhouse gas, into the atmosphere. Recently, the existence of anaerobic organisms that slowly oxidize methane has been reported and these also appear to make a contribution to the savaging of methane.