FIG. 1.

(A) Tc(VII) reduction and precipitation by resting cells of D. fructosovorans supplied with hydrogen (closed circles) as an electron donor. Control cultures with nitrogen (open circles) contained no added electron donor. The cells were incubated for 24 h at 23°C and pH 8.0. (B) Effect of pH on Tc(VII) reduction by D. fructosovorans. Hydrogen was supplied as the electron donor, and the cells were incubated at room temperature (23°C) and pH 4.5 (open circles), 5.5 (closed triangles), 6.5 (open squares), 7.5 (open triangles), 8.0 (closed circles), or 8.5 (inverted closed triangles).