FIG 4.

Characteristics of the wild type, ΔtetH mutant, and tetH overexpression strain of A. ferrooxidans ATCC 23270 grown in 9K basal salts medium to which were added different energy sources. (A) Growth in 9K-S₄O₆²⁻ medium; (B) concentration of S₄O₆²⁻ in 9K-S₄O₆²⁻ medium; (C) growth in 9K-S⁰ medium; (D) ferrous oxidation in 9K-Fe²⁺ medium. WT, ΔtetH mutant, WT (pMSD1), and WT (pMSD1-tac-tetH) represent the wild type, ΔtetH mutant, wild type carrying plasmid pMSD1, and tetH overexpression strain of A. ferrooxidans ATCC 23270, respectively. OD 600 indicates the optical density at 600 nm. All the measurements were performed in triplicate. Each data point is given as an arithmetic mean. d, days.