The Aquificota phylum is a diverse collection of bacteria that live in harsh environmental settings. The name Aquificota was given to this phylum based on an early genus identified within this group, Aquifex, which is able to produce water by oxidizing hydrogen. They have been found in springs, pools, and oceans. They are autotrophs, and are the primary carbon fixers in their environments. These bacteria are Gram-negative, non-spore-forming rods. They are true bacteria as opposed to the other inhabitants of extreme environments, the Archaea.
The Thermoprotei is a class of the Thermoproteota.
Entomoplasmatales is a small order of mollicute bacteria.
Halobacteriales are an order of the Halobacteria, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moisture, and organic material are available. Large blooms appear reddish, from the pigment bacteriorhodopsin. This pigment is used to absorb light, which provides energy to create ATP. Halobacteria also possess a second pigment, halorhodopsin, which pumps in chloride ions in response to photons, creating a voltage gradient and assisting in the production of energy from light. The process is unrelated to other forms of photosynthesis involving electron transport; however, and halobacteria are incapable of fixing carbon from carbon dioxide.
Acidilobales are an order of archaea in the class Thermoprotei.
The Desulfurococcales are an order of the Thermoprotei, part of the kingdom Archaea. The order encompasses some genera which are all thermophilic, autotrophs which utilise chemical energy, typically by reducing sulfur compounds using hydrogen.
The Pyrodictiaceae are a family of disc-shaped anaerobic microorganisms belonging to the order Desulfurococcales, in the domain Archaea. Members of this family are distinguished from the other family (Desulfurococcaceae) in the order Desulfurococcales by having an optimal growth temperature above 100 °C, rather than below 100 °C.
In taxonomy, Halosimplex is a genus of the Halobacteriaceae.
The Veillonellaceae are a family of the Clostridia, formerly known as Acidaminococcaceae. Bacteria in this family are grouped together mainly based on genetic studies, which place them among the Bacillota. Supporting this placement, several species are capable of forming endospores. However, they differ from most other Bacillota in having Gram-negative stains. The cell wall composition is peculiar.
The Negativicutes are a class of bacteria in the phylum Bacillota, whose members have a peculiar cell wall with a lipopolysaccharide outer membrane which stains gram-negative, unlike most other members of the Bacillota. Although several neighbouring Clostridia species also stain gram-negative, the proteins responsible for the unusual diderm structure of the Negativicutes may have actually been laterally acquired from Pseudomonadota. Additional research is required to confirm the origin of the diderm cell envelope in the Negativicutes.
Acidaminococcus is a genus in the phylum Bacillota (Bacteria), whose members are anaerobic diplococci that can use amino acids as the sole energy source for growth. Like other members of the class Negativicutes, they are gram-negative, despite being Bacillota, which are normally gram-positive.
Actinocatenispora is a genus in the phylum Actinomycetota (Bacteria).
Armatimonadota is a phylum of gram-negative bacteria.
The Nakamurella is a genus of bacteria.
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.
Haloferacaceae is a family of halophilic, chemoorganotrophic or heterotrophic archaea within the order Haloferacales. The type genus of this family is Haloferax. Its biochemical characteristics are the same as the order Haloferacales.
Carboxydothermus is a genus of thermophilic, anaerobic bacteria from the family of Thermoanaerobacteraceae.
The Eggerthellaceae are a family of Gram-positive, rod- or coccus-shaped Actinomycetota. It is the sole family within the order Eggerthellales.
Natrialbales is an order of halophilic, chemoorganotrophic archaea within the class Haloarchaea. The type genus of this order is Natrialba.
Haloferacales is an order of halophilic, chemoorganotrophic or heterotrophic archaea within the class Haloarchaea. The type genus of this order is Haloferax.
