The Methylocystaceae are a family of bacteria that are capable of obtaining carbon and energy from methane

Methane

Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

. Such bacteria are called methanotroph

Methanotroph

Methanotrophs are bacteria that are able to metabolize methane as their only source of carbon and energy. They can grow aerobically or anaerobically and require single-carbon compounds to survive...

s, and in particular the Methylocystaceae comprise the type II methanotrophs, which are structurally and biochemically distinct from the Methylococcaceae

Methylococcaceae

The Methylococcaceae are a family of bacteria that obtain their carbon and energy from methane, called methanotrophs. They comprise the type I methanotrophs, in contrast to the Methylocystaceae or type II methanotrophs...

 or type I methanotrophs.

In this family methane is oxidized to form formaldehyde

Formaldehyde

Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

, which is assimilated by the serine pathway. This involves combining formaldehyde and glycine

Glycine

Glycine is an organic compound with the formula NH2CH2COOH. Having a hydrogen substituent as its 'side chain', glycine is the smallest of the 20 amino acids commonly found in proteins. Its codons are GGU, GGC, GGA, GGG cf. the genetic code.Glycine is a colourless, sweet-tasting crystalline solid...

 to form serine

Serine

Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...

, which may be converted into glyceraldehyde

Glyceraldehyde

Glyceraldehyde is a triose monosaccharide with chemical formula C3H6O3. It is the simplest of all common aldoses. It is a sweet, colorless, crystalline solid that is an intermediate compound in carbohydrate metabolism...

 and thus into other organic molecules. They can also fix nitrogen, like many other members of the order Rhizobiales

Rhizobiales

Rhizobiales is an order of alpha proteobacteria. They are gram-negative.The rhizobia, which fix nitrogen and are symbiotic with plant roots, appear in several different families here. The Bradyrhizobiaceae, Hyphomicrobiaceae, Phyllobacteriaceae, and Rhizobiaceae are the four families that contain...

. The cells contained paired internal membranes which are arranged towards their periphery.