The chromate resistance phenotype of some yeast mutants correlates with a lower level of Cr(V)-species generated in the extra-cellular medium

Abstract

The paper describes the selection of chromate-resistant mutants of the yeast Pichia guilliermondii with a higher chromate-reducing activity and reports the EPR-study of Cr(V)-generation in the extra-cellular medium during the reduction of chromate by the yeast culture. It is shown that the reduction of chromate to Cr(III) species runs through the extra-cellular generation of Cr(V)-intermediate(s), thus supporting the assumption about the existence of an extra-cellular pathway of Cr(VI)-reduction. Furthermore, it is demonstrated that the chromate-resistance phenotype of tested mutants correlates with a lower stationary level of Cr(V)-species in the medium. It is thus suggested that isolated mutants can be used as sources of Cr(III)-biocomplexes due to their ability to effectively reduce chromate to Cr(III)-chelates with potential pharmacological applications.

Metallic Nanoparticles Obtained via “Green” Synthesis as a Platform for Biosensor Construction

“…We discovered the phenomenon of extracellular bioreduction of Cr(VI) through Cr(V) to Cr(III) by some yeasts, including baker's yeast as well as non-conventional yeasts (Candida guilliermondii, Ogataea polymorpha, etc.) [52][53][54][55]. The soluble stable green biocomplexes (gCr 2 O 3 NPs) generated outside the yeast cells were isolated.…”