The Thermoprotei is a class of the Thermoproteota.
Methanococcus is a genus of coccoid methanogens of the family Methanococcaceae. They are all mesophiles, except the thermophilic M. thermolithotrophicus and the hyperthermophilic M. jannaschii. The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise and it was the first archaeal genome to be completely sequenced, revealing many novel and eukaryote-like elements.
Methanobacteriales is an order of archaeans in the class Methanobacteria. Species within this order differ from other methanogens in that they can use fewer catabolic substrates and have distinct morphological characteristics, lipid compositions, and RNA sequences. Their cell walls are composed of pseudomurein. Most species are Gram-positive with rod-shaped bodies and some can form long filaments. Most of them use formate to reduce carbon dioxide, but those of the genus Methanosphaera use hydrogen to reduce methanol to methane.
In taxonomy, the Methanococcales are an order of the Methanococci.
In the taxonomy of microorganisms, the Methanomicrobiales are an order of the Methanomicrobia. Methanomicrobiales are strictly carbon dioxide reducing methanogens, using hydrogen or formate as the reducing agent. As seen from the phylogenetic tree based on 'The All-Species Living Tree' Project the family Methanomicrobiaceae is highly polyphyletic within the Methanomicrobiales.
In taxonomy, the Methanocaldococcaceae are a family of microbes within the order Methanococcales. It contains two genera, the type genus Methanocaldococcus and Methanotorris. These species are coccoid in form, neutrophilic to slightly acidophilic, and predominantly motile, and they have a very short generation period, from 25 to 45 minutes under optimal conditions. They produce energy exclusively through the reduction of carbon dioxide with hydrogen. Some species have been found in marine hydrothermal vents.
In taxonomy, the Methanocorpusculaceae are a family of microbes within the order Methanomicrobiales. It contains exactly one genus, Methanocorpusculum. The species within Methanocorpusculum were first isolated from anaerobic digesters and anaerobic wastewater treatment plants. In the wild, they prefer freshwater environments. Unlike many other methanogenic archaea, they do not require high temperatures or extreme salt concentrations to live and grow.
In taxonomy, the Methanosarcinaceae are a family of the Methanosarcinales.
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, Methanococcoides is a genus of the Methanosarcinaceae.
In taxonomy, Methanohalobium is a genus of the Methanosarcinaceae. Its genome has been sequenced. The genus contains one species, M. evestigatum.
In taxonomy, Methanolobus is a genus of methanogenic archaea within the Methanosarcinaceae. These organisms are strictly anaerobes and live exclusively through the production of methane, but the species within Methanolobus cannot use carbon dioxide with hydrogen, acetate or formate, only methyl compounds. The cells are irregular coccoid in form and approximately 1 μm in diameter. They do not form endospores. They are Gram negative and only some are motile, via a single flagellum. They are found in lake and ocean sediments that lack oxygen.
In taxonomy, Methanomethylovorans is a genus of microorganisms with the family Methanosarcinaceae. This genus was first described in 1999. The species within it generally live in freshwater environments, including rice paddies, freshwater sediments and contaminated soil. They produce methane from methanol, methylamines, dimethyl sulfide and methanethiol. With the exception of M. thermophila, which has an optimal growth temperature of 50 °C, these species are mesophiles and do not tend to grow at temperatures above 40 °C.
In taxonomy, Methanosalsum is a genus of microbes within the family Methanosarcinaceae. This genus contains two species.
Haladaptatus is a genus of halophilic archaea in the family of Halobacteriaceae. The members of Haladaptatus thrive in environments with salt concentrations approaching saturation
Haloarcula is a genus of extreme halophilic Archaea in the class of Halobactaria.
Halobaculum is a genus of the Halorubraceae.
In taxonomy, Halovivax is a genus of the Natrialbaceae. Some species of Halovivax are halophiles and have been found in Iran's Aran-Bidgol hypersaline lake.
Methanocalculus is a genus of the Methanomicrobiales, and is known to include methanogens.
Methanohalophilus mahii is an obligately anaerobic, methylotrophic, methanogenic cocci-shaped archaeon of the genus Methanohalophilus that can be found in high salinity aquatic environments. The name Methanohalophilus is said to be derived from methanum meaning "methane" in Latin; halo meaning "salt" in Greek; and mahii meaning "of Mah" in Latin, after R.A. Mah, who did substantial amounts of research on aerobic and methanogenic microbes. The proper word in ancient Greek for "salt" is however hals (ἅλς). The specific strain type was designated SLP and is currently the only identified strain of this species.
