Methanotrophs (sometimes called
methanophiles) are
prokaryotes that are able to
metabolize methane as their only source of
carbon and
energy. They can grow
aerobically or
anaerobically and require single-carbon
compounds to survive. Under aerobic conditions, they combine
oxygen and methane to form
formaldehyde, which is then incorporated into organic compounds via the serine pathway or the ribulose monophosphate (RuMP) pathway. Type I methanotrophs are part of the
Gammaproteobacteria and they use the RuMP pathway to assimilate carbon. On the other hand, type II methanotrophs are part of the
Alphaproteobacteria and utilize the Serine pathway of carbon assimilation. They also characteristically have a system of internal membranes within which methane
oxidation occurs. Methanotrophs occur mostly in soils, and are especially common near environments where methane is produced. Their habitats include oceans, mud, marshes, underground environments, soils, rice paddies and landfills. They are of special interest to researchers studying
global warming, as they are significant in the global methane budget.
