Effects of different compounds of metals and of their mixtures on the growth and survival of Thiobacillus ferrooxidans.

The iron oxidation by Thiobacillus ferrooxidans was studied in the presence of different concentrations of metals as sulphates, chlorides, nitrates, and in some other compounds. The bacteriological oxidation of ferro-ions develops in all solutions in nearly the same way, with the only difference that, as the ion concentration increases, the beginning of measurable oxidation is postponed, i.e., with ion concentration increasing, the lag-phase expands. When salts are mixed in different proportions, the toxic concentration of such a mixture corresponds, in a defined way, to the total of salts, i.e., of their ions.