Table 1.

Free energy changes of some reactions involved in the degradation of fatty acids and alcohols to methane. Calculations based on Thauer et al. 1977 [45].

Reaction	ΔG°′ (kJ/mol)
ethanol + H2O → acetate− + H+ + 2 H2	+ 9.6
propionate + 2 H2O → acetate− + H+ + CO2 + 3 H2	+ 76
butyrate + 2 H2O → acetate− + 2 H2	+ 48
acetate− + 2 H2O → 2 CO2 + 4 H2	+ 96
4 H2 + CO2 → CH4 + 2 H2O	−131
4 formate + 4 H+ → CH4 + 3 CO2 + 2 H2O	−145
CO2 + H2 → formate + H+	−4.5