Fig. 1.

(a and b) Transformations of NO₃⁻ and Fe²⁺ by Acidovorax sp. 2AN in batch reactors using different media. NO₃⁻ was present in all of the replicates at an initial concentration of 4.6 to 6 mM. When present, Fe²⁺ and acetate were present at initial concentrations of 8 to 8.4 mM and 1.5 to 1.7 mM, respectively. Medium O (organotrophic) contained only acetate as the electron donor, medium C (chemolithotrophic) contained only Fe²⁺ as the electron donor, and medium M (mixotrophic) contained both acetate and Fe²⁺. The data for heat-killed controls are presented in the supplemental material. (c) Comparative growth of strain 2AN in different media when sequentially transferred for 30 days. The data are presented as mean ± the standard deviations (n = 3). When not shown, error bars are smaller than the symbol size.