Table 3 Gibbs free energy of reaction (∆rG), maximum theoretical CH4 production (assuming complete reaction of limiting substrate), and observed CH4 production efficiency (as % theoretical max) for hydrogenotrophic methanogenesis under conditions assayed in this study.
Temp. [˚C] | Pressure [mbar] | H2:CO2 [%] | ∆rG [kJ/mol C] | Max. theoretical CH4 [µmol] | Avg. ± Std. Err. CH4 production [% Theoretical Max] |
|---|---|---|---|---|---|
0 | 1500 | 80:20 | − 117.6 | 859 | 3.22 ± 0.67 |
0 | 1500 | 2.9:92.5 (Mars mix) | − 113.5 | 31.1 | 0.010 ± 0.003 |
30 | 1500 | 80:20 | − 118.0 | 774 | 8.06 ± 1.90 |
30 | 1500 | 2.9:92.5 (Mars mix) | − 113.5 | 28.1 | 3.35 ± 0.91 |
0 | 7–12 | 80:20 | − 93.2 to − 95.6 | 9.37–16.1 | < 0.01 |
0 | 7–12 | 2.9:92.5 (Mars mix) | − 89.1 to − 91.6 | 0.340–0.582 | < 0.01 |
