Abstract

The use of microorganisms in mining processes is a technology widely employed around the world. Leaching bacteria are characterized by having resistance mechanisms for several metals found in their acidic environments, some of which have been partially described in theAcidithiobacillusgenus (mainly onferrooxidansspecies). However, the response to copper has not been studied in the psychrotolerantAcidithiobacillus ferrivoransstrains. Therefore, we propose to elucidate the response mechanisms ofA. ferrivoransACH to high copper concentrations (0-800 mM), describing its genetic repertoire and transcriptional regulation. Our results show thatA. ferrivoransACH can grow in up to 400 mM of copper. Moreover, we found the presence of several copper-related makers, belonging tocopandcussystems, as well as rusticyanins and periplasmaticacopprotein in the genome. Interestingly, the ACH strain is the only one in which we find three copies ofcopBandcopZgenes. Moreover, transcriptional expression showed an up-regulation response (acop, copZ, cusA, rusA,andrusB) to high copper concentrations. Finally, our results support the important role of these genes inA. ferrivoranscopper stress resistance, promoting the use of the ACH strain in industrial leaching under low temperatures, which could decrease the activation times of oxidation processes and the energy costs.