Minimum aeration in Acidithiobacillus ferrooxidans cultures required to maintain substrate oxidation without oxygen limitation

The volumetric oxygen transfer coefficient (k_La) 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 O₂ 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 6.250 and 3.125 μmol O₂ l^-1 for the oxidation of ferrous iron and elemental sulphur, respectively. The (k_La)_crit values required to maintain oxygen-unlimited substrate oxidation for ferrous iron and elemental sulphur were 7.70 and 4.88 h_-1, respectively.