| Methanobacteria | |
|---|---|
 | |
| Methanothermobacter thermautotrophicus | |
Scientific classification  | |
| Domain: | Archaea |
| Kingdom: | Euryarchaeota |
| Class: | Methanobacteria Boone 2002 |
| Order | |
| Synonyms | |
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In taxonomy, the Methanobacteria are a class of the Euryarchaeota. [1] Several of the classes of the Euryarchaeota are methanogens and the Methanobacteria are one of these classes.
Methanobacteria can be used in biomass conversion as well as energy production through Anaerobic digestion (AD) process. Microbial community is used in Anaerobic digestion(AD) to convert organic wastes into clean energy by reducing chemical and biological oxygen demand in the wastes. [2] Solid-state anaerobic digestion, which contains six genera of methanogens including Methanobacteria, can ferment rice straw and then produce methane. Since conventional treatment is burning rice straw in field, applying Methanobacteria to waste disposal process can reduce the air pollution caused by straw burning and also alleviate energy shortage problem, especially in rural areas. [3] During biomethanation process, insoluble organic material and higher molecular mass compounds will first be transformed into simple carbon compounds. These break-down products will then be fermented to acetic acid, hydrogen and carbon dioxide. Eventually, the acetic acids can be fermented by different methanogenic bacteria to produce methane. [4]
The product of Methanobacteria in human body can be used to test diseases. Methane in breath is produced by anaerobic methanobacteria in human colon as a metabolic end product. [5] The status of Methanobacteria product detected in breath tests can be used to evaluate patients' particular gastrointestinal disorders. It is shown that the proportion of breath methane excreters among patients with colorectal cancer is much higher than that of normal people. However, methane breath status might be influenced by variable factors existing in diagnostic procedures, limiting the usage of breath methane test in cancer diagnosis. [6]
Euryarchaeota is a phylum of archaea. Euryarchaeota are highly diverse and include methanogens, which produce methane and are often found in intestines, halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes, which generally live at temperatures between 41 and 122 °C. They are separated from the other archaeans based mainly on rRNA sequences and their unique DNA polymerase.
The Thermoprotei is a class of the Thermoproteota.
In taxonomy, the Methanopyri are a class of the Euryarchaeota.
In taxonomy, the Thermoplasmata are a class of the Euryarchaeota.
In taxonomy, the Thermoplasmatales are an order of the Thermoplasmata. All are acidophiles, growing optimally at pH below 2. Picrophilus is currently the most acidophilic of all known organisms, being capable of growing at a pH of -0.06. Many of these organisms do not contain a cell wall, although this is not true in the case of Picrophilus. Most members of the Thermotoplasmata are thermophilic.
In taxonomy, the Thermococci are a class of microbes within the Euryarchaeota.
In the taxonomy of microorganisms, the Methanomicrobia are a class of the Euryarchaeota.
Methanococci is a class of methanogenic archaea in the phylum Euryarchaeota. They can be mesophilic, thermophilic or hyperthermophilic.
In taxonomy, the Methanobacteriales are an order of the Methanobacteria. Species within this order differ from other methanogens in that they can use fewer catabolic substrates and have distinct morphological characteristics, lipid compositions, and RNA sequences. Their cell walls are composed of pseudomurein. Most species are Gram-positive with rod-shaped bodies and some can form long filaments. Most of them use formate to reduce carbon dioxide, but those of the genus Methanosphaera use hydrogen to reduce methanol to methane.
In taxonomy, the Methanopyrales are an order of microbes within the class methanopyri.
In taxonomy, the Methanosarcinales are an order of the Methanomicrobia.
In taxonomy, the Methanopyraceae are a family of the Methanopyrales. This family contains only one genus, which contains only one species, Methanopyrus kandleri. It is chemolitoautotrophic and its cells are bar-shaped. It can grow comfortably at a temperature of 98 °C and can survive at temperatures as high as 110 °C, making it the most thermophilic known methanogen. It has been found to live in hydrothermal vents.
In taxonomy, the Methanosaetaceae are a family of microbes within the order Methanosarcinales. All species within this family use acetate as their sole source of energy.
Methanocaldococcus formerly known as Methanococcus is a genus of coccoid methanogen archaea. They are all mesophiles, except the thermophilic M. thermolithotrophicus and the hyperthermophilic M. jannaschii. The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise and it was the first archaean genome to be completely sequenced, revealing many novel and eukaryote-like elements.
Aciduliprofundum is a genus of the Euryarchaeota.
In taxonomy, Methanosaeta is a genus of microbes within Methanosaetaceae. Like other species in this family, those of Methanosaeta metabolize acetate as their sole source of energy. The genus contains two species, Methanosaeta concilii, which is the type species and Methanosaeta thermophila. For a time, some scientists believed there to be a third species, Methanosaeta soehngenii, but because it has not been described from a pure culture, it is now called Methanothrix soehngenii.
In taxonomy, Methanohalophilus is a genus of the Methanosarcinaceae.
In taxonomy, Methanotorris is a genus of the Methanocaldococcaceae. The organisms in this genus differ from those of Methanothermococcus in that they are hyperthermophiles and from those of Methanocaldococcus in that they have no flagella, are not motile, and do not require selenium to grow. These microbes have not been shown to cause any illnesses.
In taxonomy, Methanothermococcus is a genus of the Methanococcaceae. The cells are shaped like irregular bars and tend to be Gram-negative. They are mobile via polar flagella. They require acetate to grow.
In taxonomy, Methanospirillum is a genus of microbes within the family Methanospirillaceae. All its species are methanogenic archaea. The cells are bar-shaped and form filaments. Most produce energy via the reduction of carbon dioxide with hydrogen, but some species can also use formate as a substrate. They are Gram-negative and move using archaella on the sides of the cells. They are strictly anaerobic, and they are found in wetland soil and anaerobic water treatment systems.
Brusa, T.; Conca, R.; Ferrara, A.; Ferrari, A.; Pecchioni, A. (December 14, 2005). "The presence of methanobacteria in human subgingivai piaque". Journal of Clinical Periodontology. 14 (8): 470–471. doi:10.1111/j.1600-051X.1987.tb02254.x. PMID 3308971.