GROWTH OF THIOBACILLUS-FERROOXIDANS UNDER ELECTROCHEMICAL REDUCTION OF INORGANIC ENERGY-SOURCE USED

An electrolytic cell was designed and constructed for the fermentation of T. ferrooxidans using Fe2+ as the energy-supplying substrate. The Fe3+ produced by T. ferrooxidans by fermentation is continuously reduced to Fe2+ in the electrolytic cell. A suitable version of the electrolytic cell permitted the elimination of most inorganic solid matter (precipitate) from the fermentation process. The fermentation of T. ferrooxidans was carried out with and without the electrolytic cell. Fermentation with the cell yielded significant rises both in the maximum obtainable growth rate and the biomass concentration. The experimental data are discussed and the theoretical substrate consumption coefficient was calculated for Fe2+ as a function of the pH and the coefficient was compared with the experimental results.