Non-Ferrous Metal Industry Waste Disposal Sites As A Source Of Poly-Extremotolerant Bacteria

Abstract

Waste disposal sites from non-ferrous metal industry constitute environments very hostile for life due to the presence of very specialized abiotic factors (pH, salt concentration, heavy metals content). In our experiments microflora of two waste disposal sites in Slovakia – brown mud disposal site from aluminium production near Ziar nad Hronom and nickel sludge disposal site near Sered - was analyzed for cultivable bacteria. Isolated bacteria were characterized by a combination of classical microbiological approaches and molecular methods and the most of isolated bacteria shown a poly-extremotolerant phenotype. The most frequently halotolerant (resistant to the high level of salt concentrations) and alkalitolerant (resistant to the high pH level) bacteria belonging to the Actinobacteria class were detected. The most of bacteria shown very high level of heavy metal resistance e.g. more than 500 μg/ml for Zn²⁺ or Cu²⁺. Based on our data, waste disposal sites thus on one side represents an important environmental burden but on other side they are a source of new poly-extremotolerant bacterial strains and species possibly used in many biotechnology and bioremediation applications.