/mɛˈθæn ə dʒən/

noun

Any microorganism capable of methanogenesis. All known methanogens are archaea and are generally strict anaerobes. Methanogens are common in mud and wetland habitats and in the digestive tracts of ruminants and humans. Many methanogens only growth with simple substrates such as CO2/H2, acetate, methanol, and methylamines.