Microbiological Mining

Isolation and Characterization ofAcidithiobacillus ferrooxidansStrain D3-2 Active in Copper Bioleaching from a Copper Mine in Chile

“…The iron-oxidizing bacterium Acidithiobacillus ferrooxidans is considered one of the most important microorganisms in the bioleaching of sulfide ores. [1][2][3][4][5][6][7][8] This might be due to its ability to utilize both Fe 2þ and sulfur moieties in sulfide ores for growth. It is known that metal ions are solubilized from metal sulfide directly by A. ferrooxidans cells (a direct bioleaching mechanism) or indirectly by ferric ion produced by A. ferrooxidans cells (an indirect bioleaching mechanism).…”

“…Symbols: A, Cu 2þ solubilized by strain D3-2 from the ore medium without sodium bisulfite; B, Cu 2þ solubilized by strain D3-2 from the ore medium with 5 mM of sodium bisulfite; C, Cu 2þ solubilized by strain ATCC 23270 from the ore medium without sodium bisulfite; D, Cu 2þ solubilized by strain ATCC 23270 from the ore medium with 5 mM of sodium bisulfite; E, Cu 2þ solubilized from the ore medium without A. ferrooxidans. iron (Fe 3þ ) plays a crucial role in the oxidation of sulfide ores and the solubilization of metal ions from sulfide ores, [1][2][3][4][5][6][7][8][9][10][11] and hence it has been believed up to now that A. ferrooxidans cells that have high iron oxidase activity have high Cu-bioleaching activity, but the iron oxidase activity of strain D3-2 was unexpectedly low among the A. ferrooxidans strains tested. During an attempt to find a clue as to on these unexpected results, we found that strain D3-2 has a unique sulfite oxidase differing greatly from A. ferrooxidans strain ATCC 23270, in that the sulfite oxidase of strain D3-2 was more highly resistant to sulfite ions than that of ATCC 23270.…”

Bioleaching of Arsenic-Bearing Copper Ores

“…A large number of microorganisms that naturally accelerate mineral and rock weathering have been identified such as Acidithiobacillus ferrooxidans (formerly knows as Thiobacillus ferrooxidans), Acidianus brierleyi, Thiobacillus caldus, Leptospirillum ferrooxidans, Acidimicrobium ferrooxidans, Sulfobacillus thermosulfidooxidans, Sulfolobus BC, and Leptospirillum ferriphilum [48,[52][53][54][55][56][57][58][59][60][61][62][63]. Microorganisms that participate in bioleaching mineral oxidation are mostly chemolithoautotrophs, which use inorganic compounds as energy and carbon sources [44].…”

Reduction of Hg2+with Reduced Mammalian Cytochromecby CytochromecOxidase Purified from a Mercury-ResistantAcidithiobacillus ferrooxidansStrain, MON-1

“…The bacterium is known as one of the most important in the bioleaching of sulfide ores, because it can oxidize ferrous iron by iron oxidase and produces ferric iron as a reaction product which is known as a potent oxidant for metal sulfide. [1][2][3][4] It has been reported that A. ferrooxidans is highly resistant to many kinds of heavy metal ions, such as Cu 2þ , Zn 2þ , Ni 2þ , Co 2þ , Mn 2þ , Cd 2þ , and Cr 3þ , but sensitive to Hg 2þ , Ag þ , and Mo 5þ . [5][6][7][8][9][10][11] Among toxic metal ions, Hg 2þ ions are the most toxic at low concentrations to the growth of A. ferrooxidans, because they have a strong affinity for thiol groups in proteins.…”