Electron paramagnetic resonance study of retention of chromium(III), chromate or dichromate(VI) and copper(II) ions by thermotolerant Hansenula polymorpha

Abstract

We report on Cr^III and Cr^VI interaction with Hansenula polymorpha, a thermotolerant yeast, studied by means of EPR spectroscopy at room temperature. Cr^III retention results in a reduced mobility of the ion, probably due to the formation of complexes immobilized on a polymeric matrix of cell. Cr^VI interaction produces stable, mobile Cr^V species, which can eventually partially decay to Cr^III species. Different reducing agents in the cell may be responsible for this behaviour, especially on cell wall components or on cytoplasmic space. A comparison with a previous study on Cu^II ion retention is also made.