Methanosarcina barkeri

Methanosarcina barkeri is the type species of the genus Methanosarcina, characterized by its wide range of substrates used in methanogenesis. While most known methanogens produce methane from H₂ and CO₂, M. barkeri can also dismutate methylated compounds such as methanol or methylamines, oxidize acetate, and reduce methylated compounds with H₂. This makes M. barkeri one of the few Methanosarcina species capable of utilizing all four known methanogenesis pathways. Even among other Methanosarcinales, which commonly utilize a broad range of substrates, the ability to grow on H₂ and CO₂ is rare due to the requirement for high H₂ partial pressure. Like other Methanosarcina species, M. barkeri has a large genome (4.53 Mbp for the type strain MS, 4.9 Mbp for the Wiesmoor strain, and 4.5 Mbp for the CM2 strain), although it is significantly smaller than the largest archaeal genome of Methanosarcina acetivorans (5.75 Mbp for the type strain C2A). It is also one of the few archaea, particularly among anaerobic species, that is genetically tractable and can be used for genetic studies.