methanotroph

Methanotrophs are bacteria that metabolize methane as their sole source of carbon and energy. They oxidize methane to methanol, using methane monooxygenase as the initial enzyme, and couple this reaction to energy production with oxygen as the terminal electron acceptor. Most methanotrophs are aerobic; some environments host microaerophilic or anaerobic methane-oxidizing consortia that involve archaea, but these are not typically referred to as methanotrophs.

Taxonomically, methanotrophy is found among several lineages, most prominently the Alpha- and Gammaproteobacteria (the Type II and Type I methanotrophs). In addition, members of the phylum Verrucomicrobia include thermophilic and acidophilic methanotrophs. The two main internal pathways for formaldehyde assimilation differ: Type I methanotrophs predominantly use the ribulose monophosphate (RuMP) pathway, while Type II methanotrophs use the serine pathway.

In methane-rich habitats such as soils, freshwater and marine sediments, landfill covers, and rice paddies, methanotrophs play a crucial role in mitigating methane emissions by removing a portion of produced methane before it escapes to the atmosphere. Their metabolism also links the global carbon and nitrogen cycles through interactions with methanogenesis and nitrogen transformations.

Applications of methanotrophs include bioremediation and biotechnological production of value-added compounds; research continues into leveraging their methane-oxidizing capabilities for greenhouse gas mitigation and sustainable biotechnology.