Kinetic model of CuS oxidation by Thiobacillus ferrooxidans and Thiobacillus thiooxidans bacteria

Kinetics of the process of microbiological oxidation of synthetic CuS performed with the involvement of pure and mixed cultures of T. ferrooxidans and T. thiooxidans bacteria were studied. The CuS oxidation with T. ferrooxidans bacteria was found to be best described by the model of inhibition of the first order with respect to the substrate and the product-inhibitor, while the process with T. thiooxidans and mixed cultures of these bacteria is best described by the first order reaction with respect to the substrate. It was also shown that the adaptation of the bacteria to the CuS rested significantly shortens the induction period and increases reaction rates. The optimum conditions of CuS oxidation were established. The yield of the reaction was established as ca. 30% and an increase in the reaction rate was observed when using mixed cultures of T. ferrooxidans i T. thiooxidans bacteria adapted to CuS at 35 degrees C, in the medium containing 1 % (wt./vol.) CuS at the initial pH of the medium of 1.82.