Minimum Aeration in <i>Acidithiobacillus ferrooxidans</i> Cultures Required to Maintain Substrate Oxidation without Oxygen Limitation

The volumetric oxygen transfer coefficient ( k L a ) was used to define the conditions necessary for minimum aeration and to eliminate potential oxygen limitation in bioleaching cultures of Acidithiobacillus ferrooxidans . The Michaelis constants for oxygen were 1.07 and 0.71 μmol O 2 l -1 for the oxidation of ferrous iron and elemental sulphur, respectively. The critical oxygen concentration, below which oxygen limitation occurred, was determined to be 6.25 and 3.125 μmol O 2 l -1 for the oxidation of ferrous iron and elemental sulphur, respectively. The ( k L a ) crit values required to maintain oxygen-unlimited substrate oxidation for ferrous iron and elemental sulphur were 7.70 and 4.88 h -1 , respectively.