Enhancement of growth and ferrous iron oxidation rates of T. Ferrooxidans by electrochemical reduction of ferric iron.

Thiobacillus ferrooxidans, the bacterium most widely used; in bioleaching or microbial desulfurization studies, was grown in an electrolytic bioreactor containing a synthetic, ferrous sulfate medium. Passage of current through the medium reduced the bacterially generated ferric iron to the ferrous iron substrate. When used in conjunction with an inoculum that had been adapted to the electrolytic growth conditions, this technique increased the protein (cell) concentration by 3.7 times, increased the protein (cell) production rate by 6.5 times, increased the yield coefficient (cellular efficiency) by 8.0 times, and increased the ferrous iron oxidation rate by 1.5 times at 29 degrees C, compared with conventional cultivation techniques. A Monod-type equation with accepted values for the maximum specific growth rate could not account for the increased growth rate under electrolytic conditions.