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.
Faecalibacterium is a genus of bacteria. Its sole known species, Faecalibacterium prausnitzii is gram-positive, mesophilic, rod-shaped, anaerobic and is one of the most abundant and important commensal bacteria of the human gut microbiota. It is non-spore forming and non-motile. These bacteria produce butyrate and other short-chain fatty acids through the fermentation of dietary fiber.
Porphyromonas is a Gram-negative, non-spore-forming, obligately anaerobic and non-motile genus from the family of Porphyromonadaceae. This genus has been found to be part of the salivary microbiome. The use of targeted 16S rRNA gene metagenomic sequencing has shown that the genus is well represented in healthy individuals from the Human Microbiome Project.
The Lachnospiraceae are a family of obligately anaerobic, variably spore-forming bacteria in the order Clostridiales that ferment diverse plant polysaccharides to short-chain fatty acids and alcohols (ethanol). These bacteria are among the most abundant taxa in the rumen and the human gut microbiota. Members of this family may protect against colon cancer in humans by producing butyric acid. Lachnospiraceae have been found to contribute to diabetes in genetically susceptible (ob/ob) germ-free mice.
Pseudobutyrivibrio is a Gram-negative, anaerobic and non-spore-forming bacterial genus from the family of Lachnospiraceae.
Anaerostipes caccae is a Gram-variable, anaerobic saccharolytic, rod-shaped butyrate-producing and acetate and lactate-utilising bacterium from the genus of Anaerostipes which has been isolated from human faeces.
Anaerostipes hadrus is a Gram-positive bacterium from the genus of Anaerostipes which has been isolated from human faeces.
Laceyella is a Gram-positive, thermophilic, spore-forming and aerobic bacterial genus from the family of Thermoactinomycetaceae. The genus Laceyella is namened after the English microbiologist John Lacey.
Flammeovirga is a Gram-negative, aerobic, non-spore-forming and chemoorganotrophic genus from the family of Flammeovirgaceae which occur in marine environments.
Cyclobacterium is a mesophilic, neutrophilic, chemoorganotrophic and aerobic bacterial genus from the family of Cyclobacteriaceae. Cyclobacterium bacteria occur in marine habitats
Anaerococcus is a genus of bacteria. Its type species is Anaerococcus prevotii. These bacteria are Gram-positive and strictly anaerobic. The genus Anaerococcus was proposed in 2001. Its genome was sequenced in August 2009. The genus Anaerococcus is one of six genera classified within the group GPAC. These six genera are found in the human body as part of the commensal human microbiota.
Dysgonomonas is a Gram-negative and facultatively anaerobic genus from the family of Dysgonomonadaceae which have been isolated from human sources. Dysgonomonas bacteria can cause gastroenteritis in immunocompromised persons
Paludibacter is a Gram-negative, strictly anaerobic, chemoorganotrophic and non-motile genus from the phylum "Bacteroidetes".
Propionicimonas is a Gram-positive, non-spore-forming and facultatively anaerobic bacterial genus from the family of Propionibacteriaceae with one known species.
Neptunomonas is an anaerobic and rod-shaped genus from the family of Oceanospirillaceae.
Caloranaerobacter is a Gram-negative, thermophilic, anaerobic and chemoorganotrophic bacterial genus from the family of Clostridiaceae.
Olsenella is a Gram-positive, non-spore-forming, obligate anaerobic and non-motile bacterial genus from the family Atopobiaceae. Olsenella is named after the microbiologist Ingar Olsen Olsenella bacteria are involved in endodontic infections in humans.
Thalassobacillus is a Gram-positive, oxidase positive, catalase negative, rod shaped and moderately halophilic genus of bacteria from the family of Bacillaceae. Single colonies are small in size.Thalassobacillus bacteria produces Meso-diaminopimelic acid. S.I. Paul et al. (2021) isolated and biochemically characterized Thalassobacillus devorans from marine sponges of the Saint Martin's Island of the Bay of Bengal, Bangladesh.
Oscillospiraceae is a family of bacteria in the class Clostridia. All Oscillospiraceae are obligate anaerobes. However, members of the family have diverse shapes, with some rod-shaped and others cocci.
Cetobacterium is a Gram-negative, pleomorphic, non-spore-forming, rod-shaped and non-motile genus of bacteria from the family of Fusobacteriaceae.
