Methane-Producing Archaea: Methanogens Methane formation occurs under strictly anoxic conditions CO2-type substrates(CO2, HCoO and co) can be used as carbon sources Methyl substrates(CH3OH, CH3NH2*, (CH3)#, (CH3)3NH#, CH3SH, ( CH3)2S) are methanogenic carbon sources。 Acetotrophic substrates such as acetate can also be used to produce methane Three classes of methanogenic substrates are known and all release free energy suitable for ATP synthesisMethane-Producing Archaea: Methanogens Methane formation occurs under strictly anoxic conditions. CO2-type substrates (CO2, HCOO- and CO) can be used as carbon sources. Methyl substrates (CH3OH, CH3NH2 + , (CH3)2NH+ , (CH3)3NH+ , CH3SH, (CH3)2S) are methanogenic carbon sources. Acetotrophic substrates such as acetate can also be used to produce methane. Three classes of methanogenic substrates are known and all release free energy suitable for ATP synthesis