Methylotroph
Encyclopedia
Methylotrophs are a diverse group of microorganism
s that can use reduced
one-carbon compounds, such as methanol
or methane
, as the carbon source for their growth; and multi-carbon compounds that contain no carbon bonds, such as dimethyl ether
and dimethylamine
. This group of microorganisms also includes those capable of assimilating reduced one-carbon compounds by way of carbon dioxide
using the ribulose bisphosphate pathway. These organisms should not be confused with methanogens
which on the contrary produce methane as a by-product from various one-carbon compounds such as carbon dioxide.
Some methylotrophs can degrade the greenhouse gas
methane
, and in this case they are called methanotroph
s. The methanotroph Methylococcus capsulatus
is used to degrade methane and other pollutants.
The abundance, purity, and low price of methanol compared to commonly used sugars make methylotrophs competent organisms for production of amino acid
s, vitamins, recombinant proteins, single-cell proteins, co-enzymes and cytochrome
s.
Methylotrophic organisms are able to grow at the expense of on or more of the compounds typically used by methophiles, but cannot use methane. Methylotrophs are a diverse group, including both Gram-negative and Gram-positive genera. None of them make resting structures like exospores and cyst and none of them have the complex intracellular membrane systems that characterize methanotrophs growing on methane
There are two sub groups:
1- obligate methylotrophs.
2- facultative methylotrophs.
Examples of methylotrophs:
Microorganism
A microorganism or microbe is a microscopic organism that comprises either a single cell , cell clusters, or no cell at all...
s that can use reduced
Redox
Redox reactions describe all chemical reactions in which atoms have their oxidation state changed....
one-carbon compounds, such as methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
or 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...
, as the carbon source for their growth; and multi-carbon compounds that contain no carbon bonds, such as dimethyl ether
Dimethyl ether
Dimethyl ether , also known as methoxymethane, is the organic compound with the formula . The simplest ether, it is a colourless gas that is a useful precursor to other organic compounds and an aerosol propellant. When combusted, DME produces minimal soot and CO, though HC and NOx formation is...
and dimethylamine
Dimethylamine
Dimethylamine is an organic compound with the formula 2NH. This secondary amine is a colorless, flammable liquified gas with an ammonia-like odor. Dimethylamine is generally encountered as a solution in water at concentrations up to around 40%...
. This group of microorganisms also includes those capable of assimilating reduced one-carbon compounds by way of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
using the ribulose bisphosphate pathway. These organisms should not be confused with methanogens
Methanogen
Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are classified as archaea, a group quite distinct from bacteria...
which on the contrary produce methane as a by-product from various one-carbon compounds such as carbon dioxide.
Some methylotrophs can degrade the greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
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...
, and in this case they 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. The methanotroph Methylococcus capsulatus
Methylococcus capsulatus
Methylococcus capsulatus is an obligately methanotrophic gram-negative, non-motile coccoid bacterium. M. capsulatus cells are encapsulated and tend to have a diplococcoid arrangement. In addition to methane, M. capsulatus is able to oxidize some organic hydrogen containing compounds such as...
is used to degrade methane and other pollutants.
The abundance, purity, and low price of methanol compared to commonly used sugars make methylotrophs competent organisms for production of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...
s, vitamins, recombinant proteins, single-cell proteins, co-enzymes and cytochrome
Cytochrome
Cytochromes are, in general, membrane-bound hemoproteins that contain heme groups and carry out electron transport.They are found either as monomeric proteins or as subunits of bigger enzymatic complexes that catalyze redox reactions....
s.
Methylotrophic organisms are able to grow at the expense of on or more of the compounds typically used by methophiles, but cannot use methane. Methylotrophs are a diverse group, including both Gram-negative and Gram-positive genera. None of them make resting structures like exospores and cyst and none of them have the complex intracellular membrane systems that characterize methanotrophs growing on 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...
There are two sub groups:
1- obligate methylotrophs.
2- facultative methylotrophs.
Obligate methlotrophs
A single obligate methylotroph (methlophilus) is known. It is Gram-negative, polarly flagelated rod capable of rapid growthy with methanol. Some strains can also utilize formaldehyde or methylamines. Carbon is assimilated via the ribulose mono phosphate pathway.Facultative methylotrophs
It is relatively widely distributed trait among heterotrophic bacteria. It may also be common among chemoautotrophs: several thiobacilli and nitrifying bacteria can drive CO2 assimilation via the Calvin-Benson cycle by formate oxidation.Examples of methylotrophs:
- Genus MethanosarcinaMethanosarcinaMethanosarcina are the only known anaerobic methanogens to produce methane using all three known metabolic pathways for methanogenesis. Most methanogens make methane from carbon dioxide and hydrogen gas. Some others utilize acetate in the acetoclastic pathway...
- Methylococcus capsulatusMethylococcus capsulatusMethylococcus capsulatus is an obligately methanotrophic gram-negative, non-motile coccoid bacterium. M. capsulatus cells are encapsulated and tend to have a diplococcoid arrangement. In addition to methane, M. capsulatus is able to oxidize some organic hydrogen containing compounds such as...
- Pichia pastorisPichia pastorisPichia pastoris is a species of methylotrophic yeast. Pichia is widely used for protein expression using recombinant DNA techniques. Hence it is used in biochemical and genetic research in academia and the biotechnical industry....