Acetate threshold concentrations suggest varying energy requirements during anaerobic respiration by Anaeromyxobacter dehalogenans

Acetate threshold concentrations were determined under chlororespiring and Fe (III)-reducing conditions for Anaeromyxobacter dehalogenans strain 2CP-C. The acetate threshold concentrations measured were 69 +/- 4, 19 +/- 8, and <1 nM for chlororespiration, amorphous Fe(III) reduction, and Fe(III) citrate reduction, respectively. Residual DeltaG values of -75.4 kJ/mol of electrons for chlororespiration and -41.5 kJ/mol of electrons for amorphous Fe(III) reduction were calculated at the acetate threshold concentration. By comparing threshold concentrations for different metabolisms in a single organism, this study provides insight into the metabolic use of energy under different growth conditions.