Cultivation of Acidithiobacillus caldus MTH-04

The bacterial strains and plasmids used in this study are listed in Table 1. The strain A. caldus MTH-04 has been deposited in the China General Microbiological Culture Collection Center (CGMCC) under accession number CGMCC 1.15711. Starkey -S⁰ liquid medium and solid Starkey-Na₂S₂O₃ plates for A. caldus growth were prepared as reported previously [34 (link)]. Chloromycetin, kanamycin, and streptomycin (Sigma, St. Louis, MO, USA) were added to a final concentration of 34, 100, and 100 μg/mL in LB medium, and 60, 100, and 100 μg/mL in both liquid and solid Starkey media, respectively. The culturing conditions were 37 °C and 200 r/min for E. coli and 40 °C and 150 r/min for A. caldus MTH-04. The cultivation method and cell measurement for A. caldus were performed according to previously reported methods [35 (link)].