Influence of redox potential on methanation of methanol by Methanosarcina barkeri in Eh-stat batch cultures

The effect of Eh on the methanogenesis of methanol by Methanosarcina barkeri strain Fusaro was studied in pH-controlled anaerobic batch cultures at 37°C, in which the Eh of the culture medium was controlled by the addition of Ti(III)-citrate at values ranging from −340 to −520 mV. The changes in Eh revealed that the specific growth rate, μ, specific methane production rate, Q_CH4 and growth yield, Y_X/S were optimum under an Eh between −430 and −520 mV, while they decreased at the higher Eh of −340 mV. The maximum values of Q_CH4 and μ under the optimum Eh condition were 210 ml CH₄/g dry cell weight·h⁻¹ and 0.11 h⁻¹, respectively.