Methanothermobacter

Methanothermobacter is a genus of thermophilic methanogenic archaea in the family Methanobacteriaceae, order Methanobacteriales, within the phylum Euryarchaeota. Members are strict anaerobes that grow optimally at high temperatures and in environments rich in hydrogen and carbon dioxide.

They are hydrogenotrophic methanogens, using H2 as the electron donor to reduce CO2 to methane via the hydrogenotrophic pathway. Some species can utilize alternative substrates such as formate under certain conditions. Methanothermobacter species typically conserve energy through methanogenesis and possess the enzymatic machinery characteristic of archaea involved in methane production, including methyl-coenzyme M reductase.

Habitat for Methanothermobacter includes hot springs, hydrothermal vents, and industrial anaerobic digesters where temperatures are elevated. In these environments, they contribute to methane formation and thus participate in the global carbon cycle, particularly in high-temperature subsurface and surface ecosystems where anaerobic conditions prevail.

Notable species within the genus include Methanothermobacter thermautotrophicus, with Methanothermobacter thermautotrophicus ΔH serving as a widely used model archaeon for genetics and biochemistry. Genomic data have been obtained for several Methanothermobacter species, aiding comparative studies of archaeal metabolism and thermophilic adaptation. Research on this genus has enhanced understanding of archaeal energy conservation, enzyme structure and function in methanogenesis, and the evolutionary biology of thermophiles.

Overall, Methanothermobacter represents a key group of thermophilic hydrogenotrophic methanogens that thrive in anaerobic, high-temperature habitats and contribute to methane production in microbial ecosystems.