Isolation and phylogenetic characterization of biomining microorganisms from actual mine operations in northern Argentina

CASTRO C; DONATI E; HIPPERDINGER M; HIPPERDINGER M; AMAR AGUSTINA; COSTA CRISTINA S; AMAR AGUSTINA; COSTA CRISTINA S; CASTRO C; DONATI E

Simposio; 2nd International symposium on extreme environments and extremophile organisms; 2019

In the Argentinean province of Jujuy, mine operations involving extraction of silver, zinc and lead are currently carried out at Chinchillas mine. This new project is located in the Andean region at 4200 meters over the sea level, 40 km far from Pirquitas mine, an old mineral site that presents shallow acid mine drainages. Also, River Pircas which that receives contribution from Pirquitas, presents acid mine drainages. The present work involved the isolation and phylogenetic characterization of biomining microorganisms from Chinchillas and Pirquitas. Samples 1, 2 and 3 were obtained from acid waters of Pirquitas. Samples 4 and 5 were collected from minerals of Chinchillas which consisted in very low-grade ore (0.2% zinc) and a dump ore (specially separated in stocks for it risk of acid drainage generation), respectively. The aim of this study was to identify naturally occurring bacteria with biomining activity, which could be used for biotechnological purposes such as bioremediation of acid mine drainages or bioleaching processes. Samples were enriched in 4 different selective liquid media for autotrophic and heterotrophic, both sulfur and/or iron oxidizers. Also, samples were enriched in the selective medium Postgate B for sulfate-reducing microorganisms (SRM). All the cultures were kept at 30 ° C for the isolation of mesophiles. Serial dilutions of enriched cultures with positive growth were transferred to solid media and incubated under the same conditions until single colony isolation. Single colonies with different morphologies were picked up, purified by repeated streaking on solid medium and finally colonies were transferred into fresh liquid medium. Molecular techniques were used to identify the isolated strains. CTAB extraction propocol was employed to isolate genomic DNA and the 16S rRNA gene was amplified by PCR, purified and sequenced using Macrogen services. The obtained sequences were subjected to BLAST homology search in order to identify the genus/species of the isolates. Only SRM were isolated from de dump ore of Chinchillas, while all the enrichments from Pirquitas presented significant growth of SRM, iron and/or sulfur oxidizing bacteria.