Widespread soil bacterium that oxidizes atmospheric methane

The global atmospheric level of methane (CH₄), the second most important greenhouse gas, is currently increasing by ∼10 million tons per year. Microbial oxidation in unsaturated soils is the only known biological process that removes CH₄ from the atmosphere, but so far, bacteria that can grow on atmospheric CH₄ have eluded all cultivation efforts. This study isolated a pure culture of a bacterium, strain MG08 that grows on air at atmospheric concentrations of CH₄. This organism, named Methylocapsa gorgona, is globally distributed in soils and closely related to uncultured members of the upland soil cluster α. CH₄ oxidation experiments and ¹³C-single cell isotope analyses demonstrated that it oxidizes atmospheric CH₄ aerobically and assimilates carbon from both CH₄ and CO₂.