Lichtgedanken 03

S C HW E R P U N K T 42 Foundation. In varied interdisciplinary projects within this initiative, resear- chers are uncovering the means by which microorganisms influence many different areas of life. In one example, the biogeoscientists are developing me- thods for remediating metal contamina- tion at mining sites all over Europe, thus allowing the land of former heap sites to be reused. Another new research re- sult offers a promising approach to this problem. Fungi »nibble« on rocks Here again, the biological version of a phenomenon known principally from the geosciences plays a major role. This time, the focus is not on the creation of rock, but rather the opposite—weathe- ring. It is not only the effects of weather and physical processes that break down rocks: organisms also play a part in weathering. The FSU researchers have now found that fungi can attack rock and, in the process, dissolve hea- vy metals from this hard material. »If one brings ground rock into contact with these fungi, metals can be relea- sed—we already knew that,« says Eri- ka Kothe. »For this reason, we wanted to investigate more closely whether this was also possible in the case of compact rock samples.« The micro- biologists suspected that the enzyme laccase plays a decisive role here. This protein is found mainly in wood-rot- ting white-rot fungi, which need it in order to break down lignin, a biopoly- mer present in wood that can only be completely broken down by fungi. For this reason, the researchers grew such a fungus, with the Latin name Schizophyllum commune (see box on the right), on black slate slabs in the labora- tory. The rock material from the spoil tip of the tourist mine Morassina or from the former uranium mining area near Ronneburg in Thuringia was then analysed after incubation with the fun- Historical photograph from 2005: point cone mine dump in Paitzdorf near Ronneburg in the former uranium mining area of Wismut. The mining landscape in eastern Thuringia has since been comprehensively reclaimed and regreened.