Uranium and Fungi

Abstract

Free-living and symbiotic fungi can interact with, and transform certain uranium species, while general metabolic activities such as decomposition of organic substances and dissolution of rocks and minerals may result in products that indirectly react with uranium. Excretion of organic acids is an important property of many fungi which can result in U-complex formation and U-ore dissolution for example, while fungal biomass can act as an efficient U biosorbent and surface/matrix for U crystallization and biomineralization. Secondary products of organic matter decomposition and mineral dissolution may result in secondary U-complex and U-mineral formation. It is not fully established whether fungi are capable of U(VI) reductive immobilization. Fungal interactions with uranium are relevant to the biogeochemistry of uranium, but also to the applied area of bioremediation. While U biosorption seems not to have a commercial future, some fungal activities may have relevance to contaminated terrestrial habitats. The dependence of almost all land plants on symbiotic mycorrhizal fungi, and the fact that mycorrhizal fungi are capable of uranium transformations may make fungal biogeochemical activity of importance in phyto- or other bioremediation strategies for soils polluted with various forms of uranium.