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.
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
Thermoanaerobacter ethanolicus is a species of thermophilic, anaerobic, non-spore-forming bacteria.
Thermoanaerobacter acetoethylicus, formerly called Thermobacteroides acetoethylicus, is a species of thermophilic, nonspore-forming bacteria.
Coprothermobacter proteolyticus, formerly Thermobacteroides proteolyticus, is a thermophilic, non-spore-forming bacteria.
Thermoanaerobacter italicus is a species of thermophilic, anaerobic, spore-forming bacteria.
Thermoanaerobacter kivui is a thermophilic, anaerobic, nonspore-forming species of bacteria.
Thermoanaerobacter mathranii is a thermophilic, anaerobic, spore-forming bacteria.
Thermoanaerobacter pseudethanolicus is a thermophilic, strictly anaerobic, spore-forming bacteria that was first found at Yellowstone National Park in the United States. Because of its ability to efficiently ferment sugars, it is thought to be of potential use in producing industrial alcohol.
Chthonomonas calidirosea is a Gram-negative bacterium and also the first representative of the new class Chthonomonadetes within the phylum Armatimonadota. The Armatimonadota were previously known as candidate phylum OP10. OP10 was composed solely of environmental 16S rRNA gene clone sequences prior to C. calidirosea's relative, Armatimonas rosea's discovery. It is now known that bacterial communities from geothermal environments, are generally constituted by, at least 5–10% of bacteria belonging to Armatimonadota.
Clostridium paradoxum is a moderately thermophilic anaerobic alkaliphile bacteria. It is motile with 2-6 peritrichous flagella and forms round to slightly oval terminal spores. Its type strain is JW-YL-7.
Thermoanaerobacter siderophilus is a dissimilatory Fe(III)-reducing, anaerobic, thermophilic bacterium that was firstly isolated from the sediment of a hydrothermal vent found near the Karymsky volcano, in the Kamchatka peninsula, Russia. It is spore-forming, with type strain SR4T.
Caldanaerobacter is a Gram-positive or negative and strictly anaerobic genus of bacteria from the family of Thermoanaerobacteraceae.
Caldanaerobius is a genus of thermophilic, obligately anaerobic bacteria from the family of Thermoanaerobacteraceae.
Caldanaerobius polysaccharolyticus is a Gram-positive thermophilic, anaerobic, non-spore-forming bacterium from the genus of Caldanaerobius which has been isolated from organic waste leachate from Hoopeston in the United States.
Caldanaerobius zeae is a Gram-positive thermophilic, anaerobic, non-spore-forming bacterium from the genus of Caldanaerobius which has been isolated from organic waste leachate in Hoopeston in the United States.
Coprothermobacterota is a phylum of nonmotile, rod-shaped bacteria.
Coprothermobacter is a genus of rod-shaped microorganisms, belonging to the bacterial family Coprothermobacteraceae of the phylum Coprothermobacterota. This taxonomic genus has been reclassified in 2018, after different phylogenetic studies showed that these bacteria represented a deeply branched taxon of the domain Bacteria; consequently, the clade including this genus has been classified in a separate phylum from Firmicutes, the phylum where it was included before reclassification.
Effusibacillus pohliae is a species of Gram positive, aerobic, thermophilic bacterium. The cells are rod-shaped and form spores. It was first isolated from Mount Melbourne, Antarctica. The species is named after the genus of Pohlia nutans, a species of moss that was colonizing the area where the type strain was isolated. E. pohliae has also been isolated from a geothermal heat pump in South Korea.
