Related Research Articles
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 or 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 H2 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.
Desulfobacter hydrogenophilus is a strictly anaerobic sulfate-reducing bacterium. It was isolated and characterized in 1987 by Friedrich Widdel of the University of Konstanz (Germany). Like most sulfate-reducing bacteria (SRB), D. hydrogenophilus is capable of completely oxidizing organic compounds (specifically acetate, pyruvate and ethanol) to CO2, and therefore plays a key role in biomineralization in anaerobic marine environments. However, unlike many SRB, D. hydrogenophilus is a facultative lithoautotroph, and can grow using H2 as an electron donor and CO2 as a carbon source. D. hydrogenophilus is also unique because it is psychrophilic (and has been shown to grow at temperatures as low as 0 °C or 32 °F). It is also diazotrophic, or capable of fixing nitrogen.
Thermothrix azorensis is a Gram-negative, facultatively chemolithoautotrophic, non-spore-forming, aerobic, thermophilic, sulfur-oxidizing bacterium of the genus Thermothrix, isolated from a hot spring on Sao Miguel Island in the Azores. T. azorensis uses thiosulfate, tetrathionate, hydrogen sulfide, and elemental sulfur for its sources of energy (chemolithoautotrophic).
Desulfuromonas acetoxidans is a species of bacteria. It is strictly anaerobic, rod-shaped, laterally flagellated and Gram-negative. It is unable to ferment organic substances; it obtains energy for growth by anaerobic sulfur respiration.
Muricauda ruestringensis is a bacterium. It is a facultatively anaerobic, appendaged bacterium first isolated from the North Sea. Its nearest relative is Zobellia uliginosa. The type strain is strain B1T.
Desulfobulbus propionicus is a Gram-negative, anaerobic chemoorganotroph. Three separate strains have been identified: 1pr3T, 2pr4, and 3pr10. It is also the first pure culture example of successful disproportionation of elemental sulfur to sulfate and sulfide. Desulfobulbus propionicus has the potential to produce free energy and chemical products.
"Syntrophothermus lipocalidus" is a bacterium, the type species and only currently described species in its genus. It is thermophilic, syntrophic, fatty-acid-oxidizing and anaerobic, and utilises isobutyrate. TGB-C1T is its type strain. Its genome has been fully sequenced.
Holophaga foetida is a bacterium, the type species of its genus. It is a homoacetogenic bacterium degrading methoxylated aromatic compounds. It is gram-negative, obligately anaerobic and rod-shaped, with type strain TMBS4. Its genome has been sequenced. It is known for its ability to anaerobically degrade aromatic compounds and the production of volatile sulfur compounds through a unique pathway.
Sulfurimonas autotrophica is a sulfur- and thiosulfate-oxidizing bacterium. It is mesophilic, and its cells are short rods, each being motile by means of a single polar flagellum. Its genome has been sequenced.
Dethiosulfovibrio peptidovorans is an anaerobic, slightly halophilic, thiosulfate-reducing bacterium. Its genome has been sequenced. It is vibrio-shaped, gram-negative and possesses lateral flagella. It is non-spore-forming. Its type strain is SEBR 4207T.
Thioalkalivibrio versutus is an obligately alkaliphilic and obligately chemolithoautotrophic sulfur-oxidizing bacteria. It was first isolated from soda lakes in northern Russia.
Desulfurobacterium thermolithotrophum is a species of autotrophic, sulphur-reducing bacterium isolated from a deep-sea hydrothermal vent. It is the type species of its genus, being thermophilic, anaerobic, Gram-negative, motile and rod-shaped, with type strain BSAT.
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.
Muricauda is a genus in the phylum Bacteroidota.
Thiobacillus denitrificans is a Gram-negative, obligate chemolithoautotroph. It was originally discovered by Martinus Beijerinck in 1904.
Caldimicrobium rimae is an extremely thermophilic, strictly anaerobic and facultatively chemolithoautotrophic bacterium from the genus of Caldimicrobium which has been isolated from the Treshchinnyi Spring from Uzon Caldera in Russia.
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 energy-rich 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).
Kyrpidia is a genus of Gram-positive, rod-shaped, thermophilic, spore-forming bacteria.
Kyrpidia tusciae is a species of Gram positive, facultatively anaerobic, thermophilic bacterium. The cells are rod-shaped and form spores.
Ann Patricia Wood is a retired British biochemist and bacteriologist who specialized in the ecology, taxonomy and physiology of sulfur-oxidizing chemolithoautotrophic bacteria and how methylotrophic bacteria play a role in the degradation of odour causing compounds in the human mouth, vagina and skin. The bacterial genus Annwoodia was named to honor her contributions to microbial research in 2017.
References
- ↑ Kodama, Y. (2004). "Sulfuricurvum kujiense gen. nov., sp. nov., a facultatively anaerobic, chemolithoautotrophic, sulfur-oxidizing bacterium isolated from an underground crude-oil storage cavity". International Journal of Systematic and Evolutionary Microbiology. 54 (6): 2297–2300. doi: 10.1099/ijs.0.63243-0 . ISSN 1466-5026. PMID 15545474.
