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Methanogenic
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. Other forms of methane production that are not coupled to ATP synthesis exist within all three domains of life. The production of methane is an important and widespread form of microbial metabolism. In anoxic environments, it is the final step in the decomposition of biomass. Methanogenesis is responsible for significant amounts of natural gas accumulations, the remainder being thermogenic. Biochemistry Methanogenesis in microbes is a form of anaerobic respiration. Methanogens do not use oxygen to respire; in fact, oxygen inhibits the growth of methanogens. The terminal electron acceptor in methanogenesis is no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanogen
Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain Archaea. All known methanogens are members of the archaeal phylum Euryarchaeota. Methanogens are common in wetlands, where they are responsible for marsh gas, and in the digestive tracts of animals such as ruminants and many humans, where they are responsible for the methane content of belching in ruminants and flatulence in humans. In marine sediments, the biological production of methane, also termed methanogenesis, is generally confined to where sulfates are depleted, below the top layers. Moreover, methanogenic archaea populations play an indispensable role in anaerobic wastewater treatments. Others are extremophiles, found in environments such as hot springs and submarine hydrothermal vents as well as in the "solid" rock of Earth's crust, kilometers below the surface. Physical description Methanogens are coccoid (sph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaea
Archaea ( ; singular archaeon ) is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria (in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties separating them from the other two domains, Bacteria and Eukaryota. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been detected only by their gene sequences in environmental samples. Archaea and bacteria are generally similar in size and shape, although a few archaea have very different shapes, such as the flat, square cells of '' Haloquadratum walsbyi''. Despite this morphological similarity to bacteria, archaea possess genes and several metabolic pathways that are more closely related to those of eukaryotes, notably for the enzymes invo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eukaryote
Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacteria and Archaea (both prokaryotes) make up the other two domains. The eukaryotes are usually now regarded as having emerged in the Archaea or as a sister of the Asgard archaea. This implies that there are only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among archaea. Eukaryotes represent a small minority of the number of organisms, but, due to their generally much larger size, their collective global biomass is estimated to be about equal to that of prokaryotes. Eukaryotes emerged approximately 2.3–1.8 billion years ago, during the Proterozoic eon, likely as flagellated phagotrophs. Their name comes from the Greek εὖ (''eu'', "well" or "good") and κάρυον (''karyon'', "nut" or "kernel"). E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanogenesis Cycle
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria. Other forms of methane production that are not coupled to ATP synthesis exist within all three domains of life. The production of methane is an important and widespread form of microbial metabolism. In anoxic environments, it is the final step in the decomposition of biomass. Methanogenesis is responsible for significant amounts of natural gas accumulations, the remainder being thermogenic. Biochemistry Methanogenesis in microbes is a form of anaerobic respiration. Methanogens do not use oxygen to respire; in fact, oxygen inhibits the growth of methanogens. The terminal electron acceptor in methanogenesis is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbe
A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in older texts. The informal synonym ''microbe'' () comes from μικρός, mikrós, "small" and βίος, bíos, "life". is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from ancient times, such as in Jain scriptures from sixth century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Becaus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coenzyme F420
Coenzyme F420 or 8-hydroxy-5-deazaflavin is a coenzyme (sometimes called a cofactor) involved in redox reactions in methanogens, in many Actinomycetota, and sporadically in other bacterial lineages. It is a flavin derivative. The coenzyme is a substrate for coenzyme F420 hydrogenase, 5,10-methylenetetrahydromethanopterin reductase and methylenetetrahydromethanopterin dehydrogenase. A particularly rich natural source of F420 is ''Mycobacterium smegmatis'', in which several dozen enzymes use F420 instead of the related cofactor FMN used by homologous enzymes in most other species. Eukaryotes including the fruit fly ''Drosophila melanogaster'' and the algae '' Ostreococcus tauri'' also use a precursor to this cofactor. Biosynthesis Coenzyme F420 is synthesized via a multi-step pathway: * 7,8-didemethyl-8-hydroxy-5-deazariboflavin synthase produces Coenzyme FO (also written F0), itself a cofactor of DNA photolyase (antenna). This is the head portion of the molecule. * 2-pho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanofuran
Methanofurans are a family of chemical compounds found in methanogenic archaea. These species feature a 2-aminomethylfuran linked to phenoxy group. At least three different end groups are recognized: R = tricarboxyheptanoyl (methanofuran), glutamyl-glutamyl (methanofuran b), tricarboxy-2-hydroxyheptanoyl (methanofuran c, see picture). Formylation of MFR Methanofuran converts to formylmethanofuran in an early stage of methanogenesis. The enzyme formylmethanofuran dehydrogenase ( EC: 1.2.99.5) formylates methanofuran using , the primary C1 source in methanogenesis. Deformylation of MFR The enzyme formylmethanofuran:tetrahydromethanopterin formyltransferase catalyzes the transfer of the formyl group from formylmethanofuran to N5 on tetrahydromethanopterin, . This enzyme has been crystallized; it contains no prosthetic group A prosthetic group is the non-amino acid component that is part of the structure of the heteroproteins or conjugated proteins, being tightly linked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Gas
Natural gas (also called fossil gas or simply gas) is a naturally occurring mixture of gaseous hydrocarbons consisting primarily of methane in addition to various smaller amounts of other higher alkanes. Low levels of trace gases like carbon dioxide, nitrogen, hydrogen sulfide, and helium are also usually present. Natural gas is colorless and odorless, so odorizers such as mercaptan (which smells like sulfur or rotten eggs) are commonly added to natural gas supplies for safety so that leaks can be readily detected. Natural gas is a fossil fuel and non-renewable resource that is formed when layers of organic matter (primarily marine microorganisms) decompose under anaerobic conditions and are subjected to intense heat and pressure underground over millions of years. The energy that the decayed organisms originally obtained from the sun via photosynthesis is stored as chemical energy within the molecules of methane and other hydrocarbons. Natural gas can be burned for he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure. Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane. The Earth's atmospheric methane concentration has increased by about 150% since 1750, and it accounts for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. It has also been detected on other pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetramethylammonium
Tetramethylammonium (TMA) or (Me4N+) is the simplest quaternary ammonium cation, consisting of four methyl groups attached to a central nitrogen atom, and is isoelectronic with neopentane. It is positively charged and can only be isolated in association with a counter-ion. Common salts include tetramethylammonium chloride and tetramethylammonium hydroxide. Tetramethylammonium salts are commonly used in chemical synthesis and are widely employed in pharmacological research. Common nomenclature In the toxicological literature, ''naturally occurring'' tetramethylammonium (anion unspecified) is often referred to by the name "tetramine". Unfortunately, this non-systematic or "trivial" name is also used for other chemical entities, including a toxic rodenticide ( Tetramethylenedisulfotetramine). Similarly, the acronym "TMA", which is frequently used for tetramethylammonium in the pharmacological literature, may also refer to the investigational drug 3,4,5-trimethoxyamphetamine, which, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethyl Sulfide
Dimethyl sulfide (DMS) or methylthiomethane is an organosulfur compound with the formula (CH3)2S. Dimethyl sulfide is a flammable liquid that boils at and has a characteristic disagreeable odor. It is a component of the smell produced from cooking of certain vegetables, notably maize, cabbage, beetroot, and seafoods. It is also an indication of bacterial contamination in malt production and brewing. It is a breakdown product of dimethylsulfoniopropionate (DMSP), and is also produced by the bacterial metabolism of methanethiol. Occurrence and production DMS originates primarily from DMSP, a major secondary metabolite in some marine algae. DMS is the most abundant biological sulfur compound emitted to the atmosphere. Emission occurs over the oceans by phytoplankton. DMS is also produced naturally by bacterial transformation of dimethyl sulfoxide (DMSO) waste that is disposed of into sewers, where it can cause environmental odor problems. DMS is oxidized in the marine atm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methanethiol
Methanethiol (also known as methyl mercaptan) is an organosulfur compound with the chemical formula . It is a colorless gas with a distinctive putrid smell. It is a natural substance found in the blood, brain and feces of animals (including humans), as well as in plant tissues. It also occurs naturally in certain foods, such as some nuts and cheese. It is one of the chemical compounds responsible for bad breath and the smell of flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH. It is very flammable. Structure and reactions The molecule is tetrahedral at the carbon atom, like methanol. It is a weak acid, with a p''K''a of ~10.4, but is about a hundred thousand times more acidic than methanol. The colorless salt can be obtained in this way: :CH3SH + CH3ONa → CH3SNa + CH3OH The resulting thiolate anion is a strong nucleophile. It can be oxidized to dimethyl disulfide: :2CH3SH + → CH3SSCH3 + H2O Further oxidation takes the disulfide to tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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