''Methylococcus capsulatus'' is an obligately

methanotroph Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to s ...

gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...

, non-motile coccoid

bacterium Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were amon ...

. ''M. capsulatus'' are thermotolerant; their cells are encapsulated and tend to have a diplococcoid shape. In addition to

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...

, ''M. capsulatus'' is able to oxidize some organic

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

containing compounds such as methanol. It has been used commercially to produce animal feed from natural gas.

Metabolism and genetics

''Methylococcus capsulatus'' is a Type I methanotroph, meaning that it is a member of the Gammaproteobacteria and that it utilizes the ribulose monophosphate pathway (RuMP) for

formaldehyde Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...

assimilation. Methane is first oxidized to methanol, which then gets converted into formaldehyde. Formaldehyde can then be (1) further oxidized to formate and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

for

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...

production or (2) assimilated into biomass. Various strains of ''M. capsulatus'' have been isolated and studied, particularly ''M. capsulatus'' (Bath), ''M. capsulatus'' (Texas) and ''M. capsulatus'' (Aberdeen). The

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding g ...

sequence of ''M. capsulatus'' (Bath) is available.

Growth requirements

''M. capsulatus'' has also been demonstrated to be thermotolerant – that is, it can grow well up to 50 °C, though its optimum growth temperature is 37 °C. In addition, ''M. capsulatus'' can live in conditions in which there is little molecular

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

available.

Commercial use

In 1999, Norferm a subsidiary of the Norwegian oil company Statoil, opened a 10,000 tons per year plant to produce animal feed from natural gas from ''M. capsulatus'' in Tjeldbergodden, Norway. The plant was shut down in 2006 because of low animal feed prices, the product had not yet been approved by the EU and high natural gas prices. In 2016

Calysta Calysta is a multinational biotechnology firm based in San Mateo, California. The company develops industrial processes that utilize microorganisms to convert methane into protein for seafood, livestock feed and other food ingredients. It oper ...

, an American biotech company, opened a plant in

Teesside Teesside () is a built-up area around the River Tees in the north of England, split between County Durham and North Yorkshire. The name was initially used as a county borough in the North Riding of Yorkshire. Historically a hub for heavy manu ...

, UK, to produce up to 100 tons of fish feed a year from natural gas using ''M. capsulatus.'' The company also announced plans to build a similar plant in

Memphis, Tennessee Memphis is a city in the U.S. state of Tennessee. It is the seat of Shelby County in the southwest part of the state; it is situated along the Mississippi River. With a population of 633,104 at the 2020 U.S. census, Memphis is the second-mos ...

with an eventual capacity of 200,000 ton a year with the agricultural business company Cargill. Another company, Unibio, also opened a plant to produce animal feed from natural gas in 2016 with a capacity of 80 tons per year using ''M. capsulatus'' in Kalundborg, Denmark. In 2018 a licensee of Unibio constructed an industrial scale plant in Ivangorod, Russia close to the border of Estonia. The plant has a capacity of 6,000 tonnes of protein per year.

References

{{Taxonbar, from=Q1948565 Gammaproteobacteria