Pseudomonadota is a major phylum of Gram-negative bacteria. The renaming of phyla in 2021 remains controversial among microbiologists, many of whom continue to use the earlier names of long standing in the literature. The phylum Proteobacteria includes a wide variety of pathogenic genera, such as Escherichia, Salmonella, Vibrio, Yersinia, Legionella, and many others. Others are free-living (nonparasitic) and include many of the bacteria responsible for nitrogen fixation.
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 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.
Gammaproteobacteria is a class of bacteria in the phylum Pseudomonadota. It contains about 250 genera, which makes it the most genera-rich taxon of the Prokaryotes. Several medically, ecologically, and scientifically important groups of bacteria belong to this class. It is composed by all Gram-negative microbes and is the most phylogenetically and physiologically diverse class of Proteobacteria.
Actinosynnema is a genus in the phylum Actinomycetota (Bacteria).
Streptomonospora amylolytica is a species of bacterium. Its type strain is YIM 91353T.
Methanogenium frigidum is a psychrophilic, H2-using methanogen from Ace Lake, Antarctica.
Demetria terragena is a species of bacteria. Its cells are gram-positive, not acid fast, non-motile, non-sporulating, irregular coccoid to short rod-shaped and microaerophilic.
Desulfuromusa ferrireducens is a species of psychrophilic, Fe(III)-reducing bacteria. It is Gram-negative, rod-shaped and motile. Its type strain is 102T.
Psychrobacter is a genus of Gram-negative, osmotolerant, oxidase-positive, psychrophilic or psychrotolerant, aerobic bacteria which belong to the family Moraxellaceae and the class Gammaproteobacteria. The shape is typically cocci or coccobacilli. Some of those bacteria were isolated from humans and can cause humans infections such as endocarditis and peritonitis. This genus of bacteria is able to grow at temperatures between −10 and 42 °C. Rudi Rossau found through DNA-rRNA hybridization analysis that Psychrobacter belongs to the Moraxellaceae. The first species was described by Juni and Heym. Psychrobacter occur in wide range of moist, cold saline habitats, but they also occur in warm and slightly saline habitats.
Jeotgalicoccus psychrophilus is a gram-positive bacterium. It is psychrophilic, it growth between 4 and 34 °C. To this also refers the selected species name. The cells are coccoid.
Psychroflexus tropicus is an obligately halophilic Cytophaga–Flavobacterium–Bacteroides group bacterium. It is Gram-negative, fine rod- to short filament-shaped, with type strain LA1T.
Arthrobacter roseus is a species of red-pigmented psychrophilic bacteria first isolated from a cyanobacterial mat. Its type strain is CMS 90r(T).
Pseudonocardia asaccharolytica is a dimethyl disulfide-degrading actinomycete, with type strain DSM 44247T.
Pseudonocardia sulfidoxydans is a dimethyl disulfide-degrading actinomycete, with type strain DSM 44248T.
Nocardioides aquaticus is a species of Gram-positive, non-motile and aerobic bacteria. Its type strain is EL-17KT.
Microlunatus lacustris is a species of Gram-positive, non-motile and aerobic bacteria. Its type strain is EL-17AT.
Streptomyces violaceolatus is a bacterium species from the genus of Streptomyces.
Thioalkalimicrobium is a defunct bacterial genus within the Gammaproteobacteria. All 4 species in the genus were reclassified to the genus Thiomicrospira in 2017.
Nocardiopsis halophila is a halophilic bacterium from the genus of Nocardiopsis which has been isolated from saline soil in Iraq.
Cryobacterium is a Gram-positive and strictly aerobic bacterial genus from the family of Microbacteriaceae.
