Resistance to Copper of some Oxidizing and Reducing Bacteria

CERTAIN types of bacteria, particularly Thiobacillus thiooxidans and Ferrobacillus ferrooxidans , are known to assist the oxidation of pyritic ores 1–4 . It has also been shown 5,6 that the rate of natural leaching of uranium from low-grade ores can be significantly increased when the leaching is done in the presence of pyrite that is itself undergoing microbiological oxidation. It is possible that a similar enhanced leaching effect could be obtained for other metals from their low-grade ores. This is of particular interest in the case of copper, since it might be anticipated that cupric ions would have a marked toxic effect on the bacteria, and enhanced leaching would be prevented.