||Caption: Methylococcus capsulatus is a Gram-negative, methylotrophic bacterium. Methylotrophs are a diverse group of microorganisms that can utilize one-carbon compounds, such as methanol, as the carbon source for their growth. The abundance and low price of methanol compared to commonly used sugars make methylotrophs competent organisms for production of amino acids, vitamins, recombinant proteins, single-cell proteins, co-enzymes and cytochromes. Methylococcus capsulatus is also a methanotrophic bacterium (methanotroph) since it uses methane as a source of carbon and energy. It primarily lives under aerobic and microaerobic conditions. M. capsulatus is used to reduce methane and other pollutants. In addition to methane, M. capsulatus is able metabolize some toxic aromatic compounds. Methanotrophs and methylotrophs can occur in extreme environments and are especially common where methane is produced. Their habitats range from oceans, mud, marshes, underground environments, soils, fresh water, rice paddies, etc. They are of special interest to researchers studying global warming. The genome sequence of M. capsulatus is known.