Geobacter is a genus of bacteria. Geobacter species are anaerobic respiration bacterial species which have capabilities that make them useful in bioremediation. Geobacter was found to be the first organism with the ability to oxidize organic compounds and metals, including iron, radioactive metals, and petroleum compounds into environmentally benign carbon dioxide while using iron oxide or other available metals as electron acceptors. Geobacter species are also found to be able to respire upon a graphite electrode. They have been found in anaerobic conditions in soils and aquatic sediment.
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.
Dehalococcoides is a genus of bacteria within class Dehalococcoidia that obtain energy via the oxidation of hydrogen and subsequent reductive dehalogenation of halogenated organic compounds in a mode of anaerobic respiration called organohalide respiration. They are well known for their great potential to remediate halogenated ethenes and aromatics. They are the only bacteria known to transform highly chlorinated dioxins, PCBs. In addition, they are the only known bacteria to transform tetrachloroethene to ethene.
Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota. It contains about 250 genera, which makes it the most genus-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically important groups of bacteria belong to this class. All members of this class are Gram-negative. It is the most phylogenetically and physiologically diverse class of the Pseudomonadota.
Shewanella is the sole genus included in the marine bacteria family Shewanellaceae. Some species within it were formerly classed as Alteromonas. Shewanella consists of facultatively anaerobic Gram-negative rods, most of which are found in extreme aquatic habitats where the temperature is very low and the pressure is very high. Shewanella bacteria are a normal component of the surface flora of fish and are implicated in fish spoilage. Shewanella chilikensis, a species of the genus Shewanella commonly found in the marine sponges of Saint Martin's Island of the Bay of Bengal, Bangladesh.
Shewanella oneidensis is a bacterium notable for its ability to reduce metal ions and live in environments with or without oxygen. This proteobacterium was first isolated from Lake Oneida, NY in 1988, hence its name.
Bacterial nanowires are electrically conductive appendages produced by a number of bacteria most notably from the Geobacter and Shewanella genera. Conductive nanowires have also been confirmed in the oxygenic cyanobacterium Synechocystis PCC6803 and a thermophilic, methanogenic coculture consisting of Pelotomaculum thermopropionicum and Methanothermobacter thermoautotrophicus. From physiological and functional perspectives, bacterial nanowires are diverse. The precise role microbial nanowires play in their biological systems has not been fully realized, but several proposed functions exist. Outside of a naturally occurring environment, bacterial nanowires have shown potential to be useful in several fields, notably the bioenergy and bioremediation industries.
Geothrix fermentans is a rod-shaped, anaerobic bacterium. It is about 0.1 µm in diameter and ranges from 2-3 µm in length. Cell arrangement occurs singly and in chains. Geothrix fermentans can normally be found in aquatic sediments such as in aquifers. As an anaerobic chemoorganotroph, this organism is best known for its ability to use electron acceptors Fe(III), as well as other high potential metals. It also uses a wide range of substrates as electron donors. Research on metal reduction by G. fermentans has contributed to understanding more about the geochemical cycling of metals in the environment.
Shewanella violacea DSS12 is a gram-negative bacterium located in marine sediment in the Ryukyu Trench at a depth of 5,110m. The first description of this organism was published in 1998 by Japanese microbiologists Yuichi Nogi, Chiaki Kato, and Koki Horikoshi, who named the species after its violet appearance when it is grown on Marine Agar 2216 Plates.
Geobacter metallireducens is a gram-negative metal-reducing proteobacterium. It is a strict anaerobe that oxidizes several short-chain fatty acids, alcohols, and monoaromatic compounds with Fe(III) as the sole electron acceptor. It can also use uranium for its growth and convert U(VI) to U(IV).
Geobacter sulfurreducens is a gram-negative metal- and sulphur-reducing proteobacterium. It is rod-shaped, aerotolerant anaerobe, non-fermentative, has flagellum and type four pili, and is closely related to Geobacter metallireducens. Geobacter sulfurreducens is an anaerobic species of bacteria that comes from the family of bacteria called Geobacteraceae. Under the genus of Geobacter, G. sulfurreducens is one out of twenty different species. The Geobacter genus was discovered by Derek R. Lovley in 1987. G. sulfurreducens was first isolated in Norman, Oklahoma, USA from materials found around the surface of a contaminated ditch.
Shewanella frigidimarina is a species of bacteria, notable for being an Antarctic species with the ability to produce eicosapentaenoic acid. It grows anaerobically by dissimilatory Fe (III) reduction. Its cells are motile and rod shaped. ACAM 591 is its type strain.
Shewanella livingstonensis is a species of bacteria. Its cells are psychrophilic, gram-negative, rod-shaped, facultatively anaerobic and motile by means of a single polar flagellum. Its type strain is LMG 19866T.
Colwellia demingiae is a psychrophilic Antarctic bacterial species with the ability to synthesize docosahexaenoic acid. It is nonpigmented, curved-rod-like in shape, exhibiting facultative anaerobic growth, and possessing an absolute requirement for sea water. Its type strain is ACAM 459T. This bacteria is named after Jody Deming, a professor and researcher at University of Washington and her research mentor, Rita Colwell.
Colwellia hornerae is a psychrophilic Antarctic bacterial species with the ability to synthesize docosahexaenoic acid. It is nonpigmented, curved-rod-like in shape, exhibiting facultative anaerobic growth and possessing an absolute requirement for sea water. Its type strain is ACAM 607T.
Colwellia rossensis is a psychrophilic Antarctic bacterial species with the ability to synthesize docosahexaenoic acid. It is non-pigmented, curved rod-like shaped, exhibiting facultative anaerobic growth and possessing an absolute requirement for sea water. Its type strain is ACAM 608T.
Colwellia psychrotropica is a psychrophilic Antarctic bacterial species with the ability to synthesize docosahexaenoic acid. It is nonpigmented, curved-rod-like in shape, exhibiting facultative anaerobic growth and possessing an absolute requirement for sea water. Its type strain is ACAM 179T.
Hentriacontanonaene is a long-chain polyunsaturated hydrocarbon produced by numerous gamma-proteobacteria primarily from the marine environment. Hentriacontanonaene was originally isolated from bacterial isolates from Antarctic sea ice cores. All isolated bacteria that produced hentriacontanonaene also produced the polyunsaturated fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Given its polyunsaturated nature it has been proposed that this molecule is produced as part of a response to maintain optimal membrane fluidity.
Dissimilatory metal-reducing microorganisms are a group of microorganisms (both bacteria and archaea) that can perform anaerobic respiration utilizing a metal as terminal electron acceptor rather than molecular oxygen (O2), which is the terminal electron acceptor reduced to water (H2O) in aerobic respiration. The most common metals used for this end are iron [Fe(III)] and manganese [Mn(IV)], which are reduced to Fe(II) and Mn(II) respectively, and most microorganisms that reduce Fe(III) can reduce Mn(IV) as well. But other metals and metalloids are also used as terminal electron acceptors, such as vanadium [V(V)], chromium [Cr(VI)], molybdenum [Mo(VI)], cobalt [Co(III)], palladium [Pd(II)], gold [Au(III)], and mercury [Hg(II)].
Microbial oxidation of sulfur is the oxidation of sulfur by microorganisms to build their structural components. The oxidation of inorganic compounds is the strategy primarily used by chemolithotrophic microorganisms to obtain energy to survive, grow and reproduce. Some inorganic forms of reduced sulfur, mainly sulfide (H2S/HS−) and elemental sulfur (S0), can be oxidized by chemolithotrophic sulfur-oxidizing prokaryotes, usually coupled to the reduction of oxygen (O2) or nitrate (NO3−). Anaerobic sulfur oxidizers include photolithoautotrophs that obtain their energy from sunlight, hydrogen from sulfide, and carbon from carbon dioxide (CO2).
