[Mathematical model of Thiobacillus ferrooxidans growth on a medium with ferrous iron]. / Matematicheskaia model' rosta Thiobacillus ferrooxidans na srede s zakisnym zhelezom.

A mathematical model is proposed for the growth of Thiobacillus ferrooxidans in the process of Fe2+ oxidation depending on the active acidity and temperature of the medium. The model was used to establish the correlation between the action of temperature and pH of the medium on the bacterial growth and oxidation of Fe2+. The range of pH values which had no effect on the bacterium is broader at 28 degrees C (from 2.5 to 2.8) than at 12 degrees C (from 2.3 to 2.4). Apparently, the growth of the bacterium and the enzymatic processes of Fe2+ oxidation are more susceptible to changes in the pH than in temperature, at least when it is lowered to 12 degrees C.

[Effect of pH and temperature on the kinetics of Fe2+ oxidation by Thiobacillus ferrooxidans]. / Vliianie pH i temperatury na kinetiku okisleniia Fe2+ Thiobacillus ferrooxidans.

A correlation has been established between the action of pH and temperature on the activity of Fe2+ oxidation by Thiobacillus ferrooxidans. The rate of Fe2+ oxidation by the bacterium is inhibited at 12 degrees C mainly due to an increase in the pH. Autooxidation of the medium upon hydrolysis of Fe3+ is inhibited at low temperatures. Apparently, the enzymes of Thiobacillus ferrooxidans involved in Fe2+ oxidation are only slightly susceptible to a decrease of temperature to 10--12 degrees C.