Candidatus Methanohalarchaeum

Abstract

Me.tha.no.hal’ar.chae.um N.L. neut. n. methanum methane; N.L. pref. methano- pertaining to methane; Gr. masc. n. hals, halos salt; N.L. neut. n. archaeum
(pertaining to archaios, -e, -on) ancient; N.L. neut. n. Methanohalarchaeum a salt-loving archaeon forming methane. The candidate genus Ca. Methanohalarchaeum includes obligately anaerobic, extremely halophilic,
neutrophilic, and moderately thermophilic methanogens with small coccoid cells producing methane by reduction of C1-methylated compounds using either
H2 or formate as electron donors. Amino acids or acetate is required as C-source for assimilation. Core membrane lipids are represented by diphytanyl glycerol
tetra- and diethers. Cells accumulate potassium as a compatible solute. They inhabit hypersaline lakes or salterns with neutral pH. The genus contains a single
candidate species Ca. M. thermophilum, which is the type species. It is amember of the class Methanonatronarchaeia within a newly proposed phylum Halobacteriota (formerly part of the phylum Euryarchaeota). DNA G+C content (mol%): 35.4 (genome of the type strain).