Methylomonas is a genus of Gram-negative, rod-shaped bacteria that are obligately methylotrophic, meaning they grow only on single-carbon compounds such as methane and methanol as their sole source of carbon and energy. Found in soils, wetlands, and aquatic sediments, they play a role in natural methane cycling by consuming methane that would otherwise reach the atmosphere. Like other methanotrophs, Methylomonas species are of industrial interest for producing single-cell protein from natural gas for animal feed, and for bioremediation of methane emissions from landfills and wastewater plants. Their metabolism is also studied for converting methane into higher-value products such as bioplastics.