Comparative studie of two fungi and their molecular interactions with uranium(VI) and europium(III)

Radionuclides are widely used in industry, medicine and research. By their use, disposal, but also by accidental release radionuclides may reach the environment. There, their mobility and their behaviour is influenced by interactions with abiotic and biotic matter. As fungi are one of the most common microorganisms in nature, they have to be taken into consideration in particular. They play an important role for preservation of the soil structure and protect plants and symbiotic partners from intoxication [1, 2]. Furthermore, they interact with radionuclides in different ways leading to an immobilization and thus a reduced toxicity and a reduced migration through the soil [3, 4, 5]. The aim of this study was to investigate the binding and the uptake of uraniumVI and europiumIII, the latter as surrogate for trivalent actinides, by the two fungi Leucoagaricus naucinus and Schizophyllum commune.

First batch experiments showed the binding of UVI and EuIII by fungi depends on initial conditions. Both fungi showed a biphasic binding of the metals and interact different depending on pH value (see figure 1). In contrast, the fungi showed increasing sorption capacities with higher initial metal concentrations and lower initial biomass. Moreover, changes of the concentration of different ions in the solution before and after incubation were investigated. Furthermore, the UVI-binding of the fungi was examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). This studies were performed in dependence on metal concentration and pH value.
In General, obtained results provide first indication that the binding behavior of both fungi is due to different binding mechanisms.