Measurements of dissolved oxygen in bioleaching reactors by optode application

The proof of concept was demonstrated by cultivating Escherichia coli, Rhodococcus erythropolis, Acidithiobacillus ferrooxidans, and Sulfobacillus thermosulfidooxidans inside 2 L bioreactors. Both optode and oxygen electrode showed similar concentration values, which demonstrates the optode is a reliable tool for oxygen measurements during bioreactor cultivation, especially of iron-oxidisers. Subsequent leaching tests, performed with fine grained residue from copper smelting and copper-rich black shale, demonstrated that the optode is resistant to mechanical wear. Therefore, the optode was found to be a suitable alternative to the amperometric oxygen probe.