Methylomicrobium

Methylomicrobium is a genus of methane-oxidizing bacteria in the family Methylococcaceae, within the order Methylococcales and the class Gammaproteobacteria. Members are Type I methanotrophs that derive energy from methane oxidation and assimilate carbon via the ribulose monophosphate (RuMP) pathway. The best characterized species include Methylomicrobium buryatellitum and Methylomicrobium alcaliphilum.

They oxidize methane to methanol using methane monooxygenase (MMO); under copper-replete conditions they typically express the particulate MMO (pMMO) and may express the soluble MMO (sMMO) under copper limitation. This initial oxidation provides both energy and formaldehyde for assimilation via the RuMP pathway, supporting growth on methane as a sole carbon and energy source in suitable environmental conditions.

Habitat for Methylomicrobium species includes methane-rich, oxygenated environments such as soils, wetlands, rice paddies, brackish waters, and aquatic systems. Some strains are alkaliphilic or halotolerant, reflecting adaptation to a range of aquatic and sedimentary niches where methane and oxygen co-occur.

Cell structure features intracytoplasmic membranes arranged as disc- or vesicle-like stacks, a hallmark of Type I methanotrophs. These membrane arrangements are associated with the sites of methane oxidation and related metabolic processes.

Ecologically, Methylomicrobium species contribute to the consumption of atmospheric and microbially produced methane in natural and engineered ecosystems. They are of interest for biotechnological applications aimed at mitigating methane emissions and converting methane to biomass or value-added products in bioreactors and bioconversion systems. Genomic analyses reveal core genes for methane oxidation and carbon assimilation, with ongoing research into diversity and physiology across the genus.