2 research outputs found
Metal Mobilization by Iron- and Sulfur-Oxidizing Bacteria in a Multiple Extreme Mine Tailings in the Atacama Desert, Chile
ArtĆculo de publicaciĆ³n ISIThe marine shore sulfidic mine tailings dump at the ChanĢaral Bay in the Atacama Desert, northern Chile, is
characterized by extreme acidity, high salinity, and high heavy metals concentrations. Due to pyrite oxidation, metals (especially
copper) are mobilized under acidic conditions and transported toward the tailings surface and precipitate as secondary minerals
(Dold, Environ. Sci. Technol. 2006, 40, 752ā758.). Depth profiles of total cell counts in this almost organic-carbon free multiple
extreme environment showed variable numbers with up to 108 cells gā1 dry weight for 50 samples at four sites. Real-time PCR
quantification and bacterial 16S rRNA gene diversity analysis via clone libraries revealed a dominance of Bacteria over Archaea
and the frequent occurrence of the acidophilic iron(II)- and sulfur-oxidizing and iron(III)-reducing genera Acidithiobacillus,
Alicyclobacillus, and Sulfobacillus. Acidophilic chemolithoautotrophic iron(II)-oxidizing bacteria were also frequently found via
most-probable-number (MPN) cultivation. Halotolerant iron(II)-oxidizers in enrichment cultures were active at NaCl
concentrations up to 1 M. Maximal microcalorimetrically determined pyrite oxidation rates coincided with maxima of the pyrite
content, total cell counts, and MPN of iron(II)-oxidizers. These findings indicate that microbial pyrite oxidation and metal
mobilization preferentially occur in distinct tailings layers at high salinity. Microorganisms for biomining with seawater salt
concentrations obviously exist in nature
Metal Mobilization by Iron- and Sulfur-Oxidizing Bacteria in a Multiple Extreme Mine Tailings in the Atacama Desert, Chile
The marine shore sulfidic mine tailings dump at the ChanĢaral
Bay in the Atacama Desert, northern Chile, is characterized by extreme
acidity, high salinity, and high heavy metals concentrations. Due
to pyrite oxidation, metals (especially copper) are mobilized under
acidic conditions and transported toward the tailings surface and
precipitate as secondary minerals (Dold, <i>Environ. Sci. Technol</i>. <b>2006</b>, <i>40</i>, 752ā758.). Depth
profiles of total cell counts in this almost organic-carbon free multiple
extreme environment showed variable numbers with up to 10<sup>8</sup> cells g<sup>ā1</sup> dry weight for 50 samples at four sites.
Real-time PCR quantification and bacterial 16S rRNA gene diversity
analysis via clone libraries revealed a dominance of <i>Bacteria</i> over <i>Archaea</i> and the frequent occurrence of the
acidophilic ironĀ(II)- and sulfur-oxidizing and ironĀ(III)-reducing
genera <i>Acidithiobacillus</i>, <i>Alicyclobacillus</i>, and <i>Sulfobacillus.</i> Acidophilic chemolithoautotrophic
ironĀ(II)-oxidizing bacteria were also frequently found via most-probable-number
(MPN) cultivation. Halotolerant ironĀ(II)-oxidizers in enrichment cultures
were active at NaCl concentrations up to 1 M. Maximal microcalorimetrically
determined pyrite oxidation rates coincided with maxima of the pyrite
content, total cell counts, and MPN of ironĀ(II)-oxidizers. These findings
indicate that microbial pyrite oxidation and metal mobilization preferentially
occur in distinct tailings layers at high salinity. Microorganisms
for biomining with seawater salt concentrations obviously exist in
nature