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.
Enterocloster clostridioformis, formerly known as Clostridium clostridioforme, is an anaerobic, motile, Gram-positive bacterium.
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
The family Thermodesulfobiaceae according to the LPSN is located within the order Thermoanaerobacterales and class Clostridia. However, according to the All-Species Living Tree Project it lies outside the clade Bacillota and the genus Caldanaerovirga does not belong to the clade, i.e. Thermodesulfobiaceae is polyphyletic.
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.
Gemmiger formicilis is a bacterium from the genus Gemmiger. It was initially assigned to the "Pseudomonadota", however 16S rRNA sequencing has led to its reclassification in the Bacillota.
Desulfomonile is a Gram negative, strict anaerobe and non-motile bacterial genus from the family of Syntrophaceae. Desulfomonile bacteria can reduce sulfur oxyanions to H2S.
Anaeromusa is a Gram-negative and obligately anaerobic bacterial genus from the family of Sporomusaceae, with one known species.
Catenibacterium is a Gram-positive, non-spore-forming and anaerobic genus from the family Erysipelotrichidae, with one known species.
Desulfofaba is a Gram-negative, anaerobic, non-spore-forming and motile bacteria genus from the family of Desulfobacteraceae.
Caldanaerobacter is a Gram-positive or negative and strictly anaerobic genus of bacteria from the family of Thermoanaerobacteraceae.
Oribacterium is a strictly anaerobic and non-spore-forming bacterial genus from the family of Lachnospiraceae.
Garciella is a Gram-positive, halotolerant, obligately anaerobic and moderately thermophilic bacterial genus from the family of Eubacteriaceae with one known species.
Mogibacterium is a Gram-positive, strictly anaerobic and non-spore-forming bacterial genus from the family of Eubacteriaceae.
Coprothermobacterota is a phylum of nonmotile, rod-shaped bacteria.
Coprothermobacteria is a taxonomic class of bacteria in the phylum Coprothermobacterota.
Coprothermobacterales is a taxonomic order of thermophilic bacteria in the class Coprothermobacteria of the phylum Coprothermobacterota.
Coprothermobacteraceae is a bacterial family of rod-shaped microorganisms, belonging to the order Coprothermobacterales, class Coprothermobacteria of the phylum Coprothermobacterota.
Coprothermobacter platensis is a species of moderately thermophilic and strictly anaerobic bacterium belonging to the family Coprothermobacteraceae within the phylum Coprothermobacterota.
