Fig. 1.
Growth of Geobacter sulfurreducens with CO and fumarate. a The oxidation of CO is coupled to the reduction of fumarate to succinate, resulting in an increase in cell protein in the culture liquid. Slight amounts of H2 are also produced. Data points are averages (±SD) for two cultures. b Fumarate is partially hydrolyzed to malate, which accumulates transiently. Over the course of the experiment, a decrease in total dicarboxylic acid concentration in the culture liquid was observed. ΔSuc, succinate produced. c G. sulfurreducens tolerates high concentrations of CO. The observed rate of CO oxidation increased with larger CO pressure in the headspace. d Uptake of CO was observed in the absence of fumarate. Small amounts of H2 and acetate were produced, but the protein concentration in the culture decreased strongly