Advances in catabolism and energy metabolism of anaerobic methane-oxidizing microorganisms

Abstract:

Methane is not only a greenhouse gas but also a potential energy substance. The balance of methane source and sink is of great significance to geochemical cycle and engineering application. Anaerobic oxidation of methane (AOM) is an important methane sink in natural habitats such as deep sea, wetland, and farmland, which plays a role in mitigating greenhouse gas emissions. The central metabolic mechanism and energy conversion pathways of methane-oxidizing microorganisms are the key to AOM coupled with the reduction of other substances. Therefore, from the perspective of electron acceptor diversity, we analyzed the physiological and biochemical processes and environmental distribution of sulfate-, nitrate/nitrite-, and metal-reducing anaerobic methane-oxidizing microorganisms, and reviewed the new anaerobic methane-oxidizing microorganisms discovered in recent years. Further, we summarized the intracellular and extracellular electron transport pathways of anaerobic methane-oxidizing microorganisms. According to the environmental distribution and reaction characteristics, we prospected the ecological significance and potential application value of anaerobic methane-oxidizing microorganisms in pollution control and energy recovery. Through the review, we aim to deepen the understanding of the microbial processes of AOM and shed light on its potential engineering application.