The green sulfur bacteria are a phylum, Chlorobiota, of obligately anaerobic photoautotrophic bacteria that metabolize sulfur.
Desulfobacterales are an order of sulfate-reducing bacteria within the phylum Thermodesulfobacteria. The order contains three families; Desulfobacteraceae, Desulfobulbaceae, and Nitrospinaceae. The bacterium in this order are strict anaerobic respirators, using sulfate or nitrate as the terminal electron acceptor instead of oxygen. Desulfobacterales can degrade ethanol, molecular hydrogen, organic acids, and small hydrocarbons. The bacterium of this order have a wide ecological range and play important environmental roles in symbiotic relationships and nutrient cycling.
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.
The enzyme methionine γ-lyase (EC 4.4.1.11, MGL) is in the γ-family of PLP-dependent enzymes. It degrades sulfur-containing amino acids to α-keto acids, ammonia, and thiols:
Propionibacterium freudenreichii is a gram-positive, non-motile bacterium that plays an important role in the creation of Emmental cheese, and to some extent, Jarlsberg cheese, Leerdammer and Maasdam cheese. Its concentration in Swiss-type cheeses is higher than in any other cheese. Propionibacteria are commonly found in milk and dairy products, though they have also been extracted from soil. P. freudenreichii has a circular chromosome about 2.5 Mb long. When Emmental cheese is being produced, P. freudenreichii ferments lactate to form acetate, propionate, and carbon dioxide (3 C3H6O3 → 2 C2H5CO2 + C2H3O2 + CO2).
Hathewaya histolytica is a species of bacteria found in feces and the soil. It is a motile, gram-positive, aerotolerant anaerobe. H. histolytica is pathogenic in many species, including guinea pigs, mice, and rabbits, and humans. H. histolytica has been shown to cause gas gangrene, often in association with other bacteria species.
Acetoanaerobium sticklandii is an anaerobic, motile, gram-positive bacterium. It was first isolated in 1954 from the black mud of the San Francisco Bay Area by T.C. Stadtman, who also named the species. A. sticklandii is not pathogenic in humans.
Synergistes jonesii is a species of bacteria, the type species of its genus. It is a rumen bacterium that degrades toxic pyridinediols including mimosine. It is obligately anaerobic, gram-negative and rod-shaped. It was discovered in 1981 by Raymond J. Jones in Hawaii and Jones' hypothesis was proven in 1986 by himself and R. G. Megarrity.
Peptoclostridium acidaminophilum is a Gram-positive bacterium species in the family Peptostreptococcaceae, notable for being an amino acid-degrading obligate anaerobe producing or utilizing H2 or formate. It is rod-shaped and motile by a polar to subpolar flagellum. Its type strain is al-2. It produces several relevant enzymes.
Desulfovibrio aminophilus is a Gram-negative, mesophilic, non-spore-forming, amino acid degrading and sulfate-reducing bacterium from the genus of Desulfovibrio which has been isolated from an anaerobic lagoon from a dairy wastewater treatment plant in Santa Fe de Bogota in Colombia.
Clostridium acetireducens is a Gram-positive, rod-shaped, anaerobic and non-motile bacterium from the genus of Clostridium which has been isolated from an anaerobic bioreactor from De Krim in the Netherlands.
Dokdonia is a genus of bacteria in the family Flavobacteriaceae and phylum Bacteroidota.
Aminiphilus is a Gram-negative, non-spore-forming and motile genus of bacteria from the family of Synergistaceae with one known species. Aminiphilus circumscriptus has been isolated from anaerobic sludge from Colombia.
Thermovirga is a Gram-negative, anaerobic and motile genus of bacteria from the family of Synergistaceae with one known species. Thermovirga lienii has been isolated from production water from an oil well from the North Sea in Norway.
Cloacibacillus evryensis is a Gram-negative, anaerobic, mesophilic, rod-shaped and non-motile bacterium from the genus of Cloacibacillus which has been isolated from sewage sludge from a wastewater treatment plant from Evry in France.
Aminobacterium colombiense is a Gram-negative, mesophilic, strictly anaerobic and non-spore-forming bacterium from the genus of Aminobacterium which has been isolated from anaerobic lagoon from a dairy wastewater treatment plant in Colombia.
Aminobacterium thunnarium is a Gram-negative, anaerobic, mesophilic and non-spore-forming bacterium from the genus of Aminobacterium which has been isolated from sludge.
Thioflavicoccus is a Gram-negative, obligately phototrophic, strictly anaerobic and motile genus of bacteria from the family of Chromatiaceae with one known species.
Oceanihabitans is a genus of marine bacterium in the family Flavobacteriaceae. It contains a single species, O. sediminis. It is aerobic, Gram-negative, rod-shaped, and motile by gliding. O. sediminis produces flexirubin pigments. It is positive for cytochrome c oxidase and catalase. O. sediminis can use glucose, mannose, maltose and adipic acid as sole carbon sources for chemoheterotrophic growth. It is a chemoorganotroph and is chemotaxonomically characterized by the presence of menaquinone 6 (MK-6). The type strain is S9-10T.
