Fig. 6

Formate production from syngas using whole cells of T. kivui. Cells were grown on 50% CO in complex medium, harvested in the end-exponential growth phase and suspended in buffer (50 mM Imidazole, 20 mM KCl, 20 mM MgSO₄, 2 mM DTE, 4 µM Resazurin, pH 7,0) to a final concentration of 1 mg/mL in anoxic serum bottles. The experiment was started by replacing the gas phase with a mixture of H₂ + CO₂ + CO (26:11:63%, 2 × 10⁵ Pa) a, b in the absence of bicarbonate and c, d in the presence of 300 mM KHCO₃. The product formation in liquid (a), c and the gas consumption in the head space (b, d) is shown over time. Squares, acetic acid; triangles, formic acid; diamonds, CO; triangles down, CO₂; circles, H₂