How Schizophyllum commune and Leucoagaricus naucinus meddle in radiometal migration

Different radiometals occur geogenically in nature. Others may be released while their industrial and medical application or accidentally e.g., after a nuclear power plant failure. In nature, their migration behavior and their possible entrance into the food chain is highly influenced by the geochemistry and the biology. Not only since the Chernobyl accident it is well known that different fungi are able to accumulate significant amounts of heavy metals and radiometals in their cells. Besides that, is was described that fungi interact with radiometals by sorption, complexation and/or biomineralization. Fungi as organic decomposers are widespread, and grow not only in the topsoil, but may reach also the subsoil and the root-free zone. They can form a large biomass and can get at least several hundred years old. All these properties taken together, fungi have high potential for precautionary radiation protection by immobilizing radionuclides in their biomass. But prior to application it is crucial to get a detailed molecular understanding of the interaction of radiometals with fungi.
Based on literature and own experiments the two fungi Schizophyllum commune and Leucoagaricus naucinus were chosen to investigate their interaction with U, Eu, Cs and Sr, with Eu serving as analogue for trivalent actinides. By applying different experimental and analytical methods such as mass spectrometry, fluorescence spectroscopy, batch and column experiments as well as electron microscopy, their interaction with radiometals was investigated qualitatively and quantitatively. The results demonstrate fundamental differences of both fungi regarding the amount of bioassociated radiometals and the kind of their interaction.