Abstract
Effect of heavy metal ions on the growth and the iron-oxidizing activity of Thiobacillus ferrooxidans were investigated.
Cupric, zinc, cadmium, and chromium ions had no effect on the growth and the iron-oxidizing activity of cell suspensions or cell-free extracts of the bacterium in high concentrations (10-3_??_10-2M). Lead ion delayed the start of the growth slightly in 10-3M, but it did not inhibit the iron-oxidizing activity of the cells in the concentration. Tin and molybdenum oxide ions inhibited both of them in the concentration above 10-3M.
Mercuric mercurous, and silver ions had the most harmful effect. In the concentration of 10-3M, each of the cations inhibited almost completely both the growth and the iron-oxidizing activity of the cells.
In the experiments with cell-free extracts it was observed that the activity of cytochrome oxidase (cytochrome a597) operating in the iron-oxidizing system of the bacterium was specifically inhibited with mercuric ion in the concentration above 5×10-4M.
