Bacterial oxidation of ferrous iron by Acidithiobacillus ferrooxidans in the pH range 2.5-7.0

Abstract

The oxidation of ferrous iron by Acidithiobacillus ferrooxidans in the pH range 2.5-7.0 was characterized. In order to measure the rate of bacterial oxidation of ferrous iron with A. ferrooxidans in this high pH range, a novel experimental methodology was developed. The results showed that the inhibition of ferrous iron oxidation activity by A. ferrooxidans observed at pH values above 3.0 is partially linked to the formation of ferric iron precipitates, which apparently hinder transport processes on the cell surface. By carefully controlling the amount of iron precipitates formed during the oxidation of ferrous iron in this pH range, enhanced bacterial activity was obtained.