Aquifex is a bacterial genus, belonging to phylum Aquificota. There is one species of Aquifex with a validly published name – A. pyrophilus – but "A. aeolicus" is sometimes considered as species though it has no standing as a name given it has not been validly or effectively published. Aquifex spp. are extreme thermophiles, growing best at temperature of 85 °C to 95 °C. They are members of the Bacteria as opposed to the other inhabitants of extreme environments, the Archaea.
"Aquifex aeolicus" is a chemolithoautotrophic, Gram-negative, motile, hyperthermophilic bacterium. "A. aeolicus" is generally rod-shaped with an approximate length of 2.0-6.0μm and a diameter of 0.4-0.5μm. "A. aeolicus" is neither validly nor effectively published and, having no standing in nomenclature, should be styled in quotation marks. It is one of a handful of species in the Aquificota phylum, an unusual group of thermophilic bacteria that are thought to be some of the oldest species of bacteria, related to filamentous bacteria first observed at the turn of the century. "A. aeolicus" is also believed to be one of the earliest diverging species of thermophilic bacteria. "A. aeolicus" grows best in water between 85 °C and 95 °C, and can be found near underwater volcanoes or hot springs. It requires oxygen to survive but has been found to grow optimally under microaerophilic conditions. Due to its high stability against high temperature and lack of oxygen, "A. aeolicus" is a good candidate for biotechnological applications as it is believed to have potential to be used as hydrogenases in an attractive H2/O2 biofuel cell, replacing chemical catalysts. This can be useful for improving industrial processes.
Aquifex pyrophilus is a gram-negative, non-spore forming, rod-shaped bacteria. It is one of a handful of species in the Aquificota phylum, which are a group of thermophilic bacteria that are found near underwater volcanoes or hot springs.
Sulfur-reducing bacteria are microorganisms able to reduce elemental sulfur (S0) to hydrogen sulfide (H2S). These microbes use inorganic sulfur compounds as electron acceptors to sustain several activities such as respiration, conserving energy and growth, in absence of oxygen. The final product of these processes, sulfide, has a considerable influence on the chemistry of the environment and, in addition, is used as electron donor for a large variety of microbial metabolisms. Several types of bacteria and many non-methanogenic archaea can reduce sulfur. Microbial sulfur reduction was already shown in early studies, which highlighted the first proof of S0 reduction in a vibrioid bacterium from mud, with sulfur as electron acceptor and H
2 as electron donor. The first pure cultured species of sulfur-reducing bacteria, Desulfuromonas acetoxidans, was discovered in 1976 and described by Pfennig Norbert and Biebel Hanno as an anaerobic sulfur-reducing and acetate-oxidizing bacterium, not able to reduce sulfate. Only few taxa are true sulfur-reducing bacteria, using sulfur reduction as the only or main catabolic reaction. Normally, they couple this reaction with the oxidation of acetate, succinate or other organic compounds. In general, sulfate-reducing bacteria are able to use both sulfate and elemental sulfur as electron acceptors. Thanks to its abundancy and thermodynamic stability, sulfate is the most studied electron acceptor for anaerobic respiration that involves sulfur compounds. Elemental sulfur, however, is very abundant and important, especially in deep-sea hydrothermal vents, hot springs and other extreme environments, making its isolation more difficult. Some bacteria – such as Proteus, Campylobacter, Pseudomonas and Salmonella – have the ability to reduce sulfur, but can also use oxygen and other terminal electron acceptors.
In biology, syntrophy, synthrophy, or cross-feeding is the phenomenon of one species feeding on the metabolic products of another species to cope up with the energy limitations by electron transfer. In this type of biological interaction, metabolite transfer happens between two or more metabolically diverse microbial species that live in close proximity to each other. The growth of one partner depends on the nutrients, growth factors, or substrates provided by the other partner. Thus, syntrophism can be considered as an obligatory interdependency and a mutualistic metabolism between two different bacterial species.
Champagne Pool is a prominent geothermal feature within the Waiotapu geothermal area in the North Island of New Zealand. The terrestrial hot spring is located about 30 km (20 mi) southeast of Rotorua and about 50 km (30 mi) northeast of Taupō. The name Champagne Pool is derived from the abundant efflux of carbon dioxide (CO2), similar to a glass of bubbling champagne. The hot spring was formed 900 years ago by a hydrothermal eruption, which makes it in geological terms a relatively young system. Its crater is about 65 m (213 ft) in diameter with a maximum depth around 62 m (203 ft) and is filled with an estimated volume of 50,000 m3 (1,800,000 cu ft) of geothermal fluid.
In enzymology, carbon monoxide dehydrogenase (CODH) (EC 1.2.7.4) is an enzyme that catalyzes the chemical reaction
Hydrogenobacter thermophilus is an extremely thermophilic, straight rod (bacillus) bacterium. TK-6 is the type strain for this species. It is a Gram negative, non-motile, obligate chemolithoautotroph. It belongs to one of the earliest branching order of Bacteria. H. thermophilus TK-6 lives in soil that contains hot water. It was one of the first hydrogen oxidizing bacteria described leading to the discovery, and subsequent examination of many unique proteins involved in its metabolism. Its discovery contradicted the idea that no obligate hydrogen oxidizing bacteria existed, leading to a new understanding of this physiological group. Additionally, H. thermophilus contains a fatty acid composition that had not been observed before.
Thermoanaerobacter is a genus in the phylum Bacillota (Bacteria). Members of this genus are thermophilic and anaerobic, several of them were previously described as Clostridium species and members of the now obsolete genera Acetogenium and Thermobacteroides
Nautilia profundicola is a Gram-negative chemolithoautotrophic bacterium found around hydrothermal vents in the deep ocean. It was first discovered in 1999 on the East Pacific Rise at depth of 2,500 metres (8,200 ft), on the surface of the polychaete worm Alvinella pompejana. Nautilia profundicola lives symbiotically on the dorsal hairs of A. pompejana but they may also form biofilms and live independently on the walls of hydrothermal vents. The ability of N. profundicola to survive in an anaerobic environment rich in sulfur, H2 and CO2 of varying temperature makes it a useful organism to study, as these are the conditions that are theorized to have prevailed around the time of the earliest life on earth.
Thermotoga maritima is a hyperthermophilic, anaerobic organism that is a member of the order Thermotogales. T. maritima is well known for its ability to produce hydrogen (clean energy) and it is the only fermentative bacterium that has been shown to produce Hydrogen more than the Thauer limit (>4 mol H2 /mol glucose). It employs [FeFe]-hydrogenases to produce hydrogen gas (H2) by fermenting many different types of carbohydrates.
Chlorobaculum tepidum, previously known as Chlorobium tepidum, is an anaerobic, thermophilic green sulfur bacteria first isolated from New Zealand. Its cells are gram-negative and non-motile rods of variable length. They contain chlorosomes and bacteriochlorophyll a and c.
Thermotoga elfii is a rod-shaped, glucose-fermenting bacterium. The type strain of T. elfii is SEBR 6459T. The genus Thermotoga was originally thought to be strictly found surrounding submarine hydrothermal vents, but this organism was subsequently isolated in African oil wells in 1995. A protective outer sheath allows this microbe to be thermophilic. This organism cannot function in the presence of oxygen making it strictly anaerobic. Some research proposes that the thiosulfate-reducing qualities in this organism could lead to decreased bio-corrosion in oil equipment in industrial settings.
Thermotoga naphthophila is a hyperthermophilic, anaerobic, non-spore-forming, rod-shaped fermentative heterotroph, with type strain RKU-10T.
Thermosinus carboxydivorans is an anaerobic, thermophilic, Gram-negative, carbon-monoxide-oxidizing, hydrogenogenic bacterium, the type species of its genus. It is facultatively carboxydotrophic, curved, motile, rod-shaped, with a length of 2.6–3 μm, a width of about 0.5 μm and lateral flagellation. Its type strain is Nor1T.
Carboxydothermus is a genus of thermophilic, anaerobic bacteria from the family of Thermoanaerobacteraceae.
Carboxydothermus pertinax is a thermophilic and anaerobic bacterium from the genus of Carboxydothermus which has been isolated from a hot spring on the Kyushu Island in Japan.
Caloranaerobacter is a Gram-negative, thermophilic, anaerobic and chemoorganotrophic bacterial genus from the family of Clostridiaceae.
Thermodesulfobacterium hveragerdense is a bacterial species belonging to genus Thermodesulfobacterium, which are thermophilic sulfate-reducing bacteria. This species is found in aquatic areas of high temperature, and lives in freshwater like most, but not all Thermodesulfobacterium species It was first isolated from hotsprings in Iceland.
Sulfurisphaera tokodaii is a thermophilic archaeon of the Thermoproteota phylum. This species lives can grow as a chemoheterotroph and a lithoautotroph
