FIG. 4.

Induction of caffeate respiration during acetogenesis with H₂, CO₂, and fructose or with H₂ and fructose by cell suspensions of A. woodii. Cells were grown on fructose and harvested, and cell suspensions (1.0 mg protein/ml) were incubated with fructose, H₂, and CO₂ (solid symbols) or with fructose and H₂ (open symbols) at 30°C in a shaking water bath for 10 min. Caffeate (2 mM) was added from a stock solution. At the times indicated, samples were withdrawn and analyzed to determine the caffeate (squares), acetate (triangles), and fructose (circles) concentrations as described in Materials and Methods.