Table 2. Methane production by cell suspensions of M. barkeri strains.

	M. barkeri		M. barkeri Δmtr
Substrate	CH4 produced, μmol	Rate of CH4 production, nmol·min−1·mg−1	CH4 produced, μmol	Rate of CH4 production, nmol·min−1·mg−1
N2/CO2	<1	<1	<1	<1
H2/CO2	308 ± 55	221 ± 37	<1	<1
Me	350 ± 18	328 ± 26	109 ± 5	9 ± 4
Me + H2/CO2	691 ± 39	731 ± 36	442 ± 46	422 ± 41
Me + Ac	356 ± 6	309 ± 6	491 ± 13	171 ± 20

Assays contained 500 μmol methanol and/or 500 μmol acetate and were conducted as described in Materials and Methods; gas phase was either N₂/CO₂ (80%/20%) or H₂/CO₂ (80%/20%) at 250 kPa.