A methane-producing bacterium, especially an archaean that reduces carbon dioxide to methane.
- ‘Methane is formed by a unique group of anaerobic bacteria belonging to the Archaea, the methanogens.’
- ‘Dog feces naturally contain bacteria called methanogens, which use hydrogen to break down carbon dioxide into microbial food.’
- ‘Among the archaebacteria, the genome that is most similar to yeast at all thresholds is that of the methanogen Methanosarcina mazei.’
- ‘Since the discovery that methanogens belong to the Archaea and not to the Bacteria, a number of other archaeal groups have been discovered.’
- ‘In this regard, both the phylogeny and function of archaeal selenoproteins are consistent with the argument that the archaeal ancestor was a methanogen.’