Interaction of U(VI) with Schizophyllum commune

Biosorption processes of heavy metals and actinides like uranium by fungal cells play an important role in the mobilisation or immobilisation of these elements in nature. Different sorption experiments of U(VI) with Schizophyllum commune at different initial uranium concentrations and therewith connected varying initial uranium speciation showed high uranium sorption capacities in the pH range from 4 to 7. Formed uranium complexes were investigated by means of time-resolved laser-induced fluorescence spectroscopic measurements (TRLFS). The obtained spectra show clearly differences between the emissions properties of the uranium species on fungi and the dissolved uranium species in the initial mineral medium. While the oxidation state of uranium remained unchanged during the sorption process, the uranium speciation changes significantly. Extra- and/or intracellular phosphate groups are the predominant binding places of uranium due to our first spectroscopic results. X-ray absorption fine structure spectroscopic measurements (EXAFS) were performed for a structural characterisation of formed uranium-fungi species and a verification of the TRLFS results.