Anaerobic Methane Oxidizers

Abstract

The anaerobic oxidation of methane (AOM) with sulfate as the final electron acceptor according to (CH4 + SO42− {\textrightarrow} HCO3− + HS− + H2O) is the major sink of methane in the oceans and hence a significant process in the global carbon cycle and methane budget. Anaerobic methane oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) are assumed to act as a syntrophic consortium where the archaeal partner activates and metabolizes methane, leading to an intermediate that is scavenged as electron donor by the sulfate-reducing partner. All known anaerobic methanotrophs are related to the methanogenic Euryarchaeota. Recently, much has been learned about the distribution, activity, and physiology of the ANME, however, not a single member of these groups has been obtained in culture and the biochemical functioning of AOM remains unknown.