“…They preferentially grow in acidic environments (i.e., they are acidophilic), and can even grow at pH close to zero (OTTOBONI & SATO, 2000), and such processes occur through the action of bacteria such as Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, and Acidithiobacillus thiooxidans etc. (BRIERLEY, 2010;RODRIGUES, 2015;TAO & DONGWEI, 2014;WATLING, 2006). According to Oliveira (2009), due to physiological and environmental similarities, these bacteria coexist simultaneously, intensifying the solubilization of the constituent metals of sulphide minerals, and are classified as chemoautotrophic, since they obtain energy from the oxidation of inorganic compounds such as sulphides (ALMEIDA, 2005;SILVAS, 2010), using CO 2 as the only carbon source for biomass production and are classified according to the temperature at which they develop, distinguishing themselves into: mesophiles (up to ~40 o C), moderate thermophiles (~40 -~55 o C) and extreme thermophiles (~55 -~80 o C) (CHANG et al, 2000;NAGPAL et al, 2000).…”