Methanopyrales

Methanopyrales is an order of the Archaea within the phylum Euryarchaeota (class Methanopyri). It represents a small, extremophilic lineage of methanogens that convert carbon dioxide to methane under anaerobic conditions. The order presently comprises a single described genus, Methanopyrus, whose well-known species is Methanopyrus kandleri.

Methanopyrus kandleri is a hydrogenotrophic methanogen, and it thrives in high-temperature environments. It is strictly anaerobic and utilizes molecular hydrogen as an electron donor and carbon dioxide as an electron acceptor to produce methane. It is among the most thermophilic methanogens studied, with an optimal growth temperature around 98°C and a growth range roughly from 80 to 110°C, conditions commonly found in deep-sea hydrothermal vents. The organism’s extreme thermophily makes it a focal point in studies of microbial life at high temperatures and the evolution of energy metabolism in Archaea.

Morphologically, Methanopyrus kandleri is a prokaryote with cellular features typical of archaea, including archaeal membrane lipids that are ether-linked and adapted to high-temperature stability. The genome of Methanopyrus kandleri has been sequenced, contributing to understanding of thermophilic adaptation and methanogenic pathways.

Ecologically, Methanopyrales members are associated with hot, anoxic environments such as hydrothermal systems where they contribute to methane production. They provide insights into early archaeal evolution, extreme temperature tolerance, and the diversity of methane metabolism in geothermal ecosystems.