Interactions among microfungi and pyrite-chalcopyrite mineralizations: tolerance, mineral bioleaching, metals bioaccumulation

Abandoned sulfide mines represent one of the most important causes of pollution in the world. These environments are characterized by the absence of a real soil and plant life and are colonized only by pioneer microorganisms such as bacteria and fungi. Mycelial fungi interact with mineral compounds through many direct or indirect strategies, develop a significant biomass in soil and sequester significant amounts of metals. In this study, three fungal species (Penicillium brevicompactum, P. glandicola, and a strain of Trichoderma harzianum species complex), isolated from the Libiola sulfide mine (Liguria, Italy), were tested on mineral tolerance to pyrite-chalcopyrite mineralizations, mineral bioleaching and metal accumulation. All the species were able to grow on extremely acid media enriched with sulfide mineralizations. In particular T. harzianum revealed the great capacity to bioconcentrate Ag, Cu, Cd and Zn, which were released during pyrite alteration. These results showed the microfungi active role played in the pedogenetic processes and their potential use in metal mining and bioremediation.