Penicillium species obtained from the surface waters of Berkeley Pit Lake in Butte, Montana (USA).[1] This lake was formed when an abandoned copper mine was flooded with infiltrating ground water, thus resulting in the formation of a highly acidic (pH 2.5) and metal contaminated ecosystem where only extremophiles could survive. The microorganisms that tolerate these extreme growth conditions are a precious, although very scarce, source of ...