Molecular charakterization of Thiobacillus isolates recovered from a uranium mining waste pile

In natural bioleaching systems autochtonic microorganisms are involved in the solubilization of metals from solid minerals. The widest spreaded mesophilic group of bioleaching microorganisms are the chemolithoautotrophic bacteria Thiobacillus ferrooxidans, Thiobacillus thiooxidans and Leptospirillum ferrooxidans.
From the soil samples of different sites and depths of a former uranium mine in Saxony, Germany, several Thiobacillus strains were cultured. They were classified by the use of the amplified ribosomal DNA restriction enzyme analysis (ARDREA). The genomic organization of the strains was investigated using random amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE).
All strains were affiliated to the species T. ferrooxidans. Moreover, it was possible to distinguish members belonging to the two closely related phylogenetic groups of the species - one related to the reference strain T. ferrooxidans ATCC 33020 (recovered from a uranium mine) and a second one, related to the strain 21834 (recovered from a coal mine).
By the use of the RAPD and PFGE fingerprinting methods it was demonstrated that the strains recovered from different depths differ in their genomic organization.