Evaluation of Leptospirillum spp. in the Río Tinto, a model of interest to biohydrometallurgy

Members of the Leptospirillum genus have recently been found to be not only the most representative prokaryotes in the Río Tinto, a natural extreme acidic habitat, but also in other acidic environments (AMD), as well as in biohydrometallurgical operations. The main objective of this work was to better understand and control industrial biohydrometallurgical processes by studying the role of chemolithoautotrophic bacteria of this genus in the Tinto ecosystem.Different strains of Leptospirillum were isolated from the Tinto basin and physiologically and genetically characterized by Pulsed Field Gel Electrophoresis (PFGE) and DNA microarrays. Certain metabolic capabilities, such as iron oxidation, pyrite leaching and nitrogen fixation, were determined for each strain. Complementary molecular ecology techniques (fluorescence in situ hybridization (FISH and CARD-FISH) and 16S rRNA gene cloning) were used to study the microbial diversity and the distribution of leptospirilli along the iron gradient of the Tinto ecosystem.