Biochemical and biotechnological aspects of aeration conditions in iron- and sulfur-oxidizing Acidithiobacillus ferrooxidans cultures were studied. The critical values of volumetric oxygen transfer coefficient, (kLa)crit, and oxygen concentration, Ccrit, were used to define the conditions necessary for minimum aeration and to eliminate potential oxygen limitation during substrate oxidation by themodel bioleaching culture. TheMichaelis constants for oxygenwere 1.07 and 0.61 μmol O2 l−1 for the oxidation of ferrous iron and elemental sulfur, respectively. The Ccrit values, below which oxygen limitation may occur, were 6.250 and 3.125 μmol O2 l−1, determined in respirometric experiments for the oxidation of ferrous iron and elemental sulfur, respectively. The rates of iron and sulfur oxidation were also determined at the Ccrit values by measuring the formation of ferric iron and protons in the corresponding cell suspensions. Neither iron nor sulfur oxidation was limited by oxygen at Ccrit. The (kLa)crit values required to maintain oxygen-unlimited oxidation of ferrous iron and elemental sulfur were 7.70 and 4.88 h−1, respectively.
Bibliographical noteNOTICE: this is the author’s version of a work that was accepted for publication in Hydrometallurgy. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Hydrometallurgy, [150, (2015)] DOI: 10.1016/j.hydromet.2014.09.009
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- Acidithiobacillus ferrooxidans
- Oxygen limitation
- Volumetric oxygen transfer coefficient