Eletrodos de bornita foram caracterizados na presença e na ausência de Acidithiobacillus ferrooxidans, um importante microorganismo envolvido nos processos de lixiviação de metais. A presença da bactéria modificou significativamente a interface mineral/eletrólito, aumentando a taxa de corrosão, como revelado pelas análises interferométricas, AEM, ICP e EIS. A atividade bacteriana sobre o eletro...

This minireview presents recent advances in our understanding of iron oxidation and homeostasis in acidophilic Bacteria and Archaea. These processes influence the flux of metals and nutrients in pristine and man-made acidic environments such as acid mine drainage and industrial bioleaching operations. Acidophiles are also being studied to understand life in extreme conditions and their role in ...

Bacterial adhesion to mineral surfaces plays an important role not only in bacterial survival in natural ecosystems, but also in mining industry applications. Selective adhesion was investigated with Thiobacillus ferrooxidans by using four minerals, pyrite, quartz, chalcopyrite, and galena. Escherichia coli was used as a control bacterium. Contact angles were used as indicators of hydrophobicit...

Topological analysis with a phoA gene fusion suggested that Acidithiobacillus ferrooxidans MerC, a mercury transporter, has two periplasmic loops and four transmembrane domains. Cys-23 and Cys-26 of the protein were involved in Hg(2+)-recognition/uptake, but Cys-132 and Cys-137 were not. Escherichia coli cells producing the MerC were hypersensitive to CdCl(2). In this case, mutation of His72 re...

We herein investigated the mechanisms underlying the contact leaching process in pyrite bioleaching by Acidithiobacillus ferrooxidans using scanning transmission X-ray microscopy (STXM)-based C and Fe near edge X-ray absorption fine structure (NEXAFS) analyses. The C NEXAFS analysis directly showed that attached A. ferrooxidans produces polysaccharide-abundant extracellular polymeric substances...

A large non-coding RNA, termed α-Fur, of ~1000 nt has been detected in the extreme acidophile Acidithiobacillus ferrooxidans encoded on the antisense strand to the iron-responsive master regulator fur (ferric uptake regulator) gene. A promoter for α-fur was predicted bioinformatically and validated using gene fusion experiments. The promoter is situated within the coding region and in the same ...

Jarosite [(Na+, K+, NH4+, H3O+)Fe3(SO4)2(OH)6] is an efficient scavenger for trace metals in Fe- and SO42--rich acidic water. During the biosynthesis of jarosite promoted by Acidithiobacillus ferrooxidans, the continuous supply of high oxygen levels is a common practice that results in high costs. To evaluate the function of oxygen in jarosite production by A. ferrooxidans, three groups of batc...

This paper provides an overview of hydrometallurgical copper extraction studies in which liquid technology has been used with four deposits different compositions. The sulfuric acid consumption rate and efficiency, are dependent on the initial content forms calcium compounds other impurities ore samples, were calculated, results presented herein. It was established that during leaching process,...