FIG. 1.

Chemolithoautotrophic growth of A. ferrooxidans on aerobic and anaerobic respiration with H₂ as the electron donor. (A) Time-dependent changes in cell density of strain IFO 14262 aerobically respired in the presence (•) or absence (○) of H₂ and those of JCM 7811 anaerobically respired using Fe³⁺ as an electron acceptor in the presence (▴) or absence (▵) of H₂. (B) Time-dependent changes in the concentrations of total iron (open symbols) and Fe²⁺ (closed symbols) in the presence (○ and •) or absence (▵ and ▴) of bacteria; in this case, strain JCM 7811 anaerobically respired by using Fe³⁺ as an electron acceptor. The datum points are averages of three independent determinations with the standard deviations.