INVESTIGADORES
VIERA Marisa Rosana
artículos
Título:
FISH analysis of bacterial attachment to copper sulfides in bioleaching processes.
Autor/es:
C.20- J. HUERGO, C. BERNARDELLI, M. VIERA, W. SAND, E. DONATI.
Revista:
Advanced Materials Research
Editorial:
TRANS TECH PUBLICATIONS
Referencias:
Año: 2009 vol. 71 p. 329 - 332
ISSN:
1022-6680
Resumen:
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Abstract. Bioleaching is the biological conversion of an
insoluble metal compound into a water soluble form. In this process metal
sulfides are oxidized to metal ions and sulfate by acidophilic microorganisms
capable of oxidizing Fe2+ and/or sulfur-compounds. The metal
solubilization from sulfide minerals is a chemical process which requires Fe3+
reduction. It is an environmentally friendly technique and an economical method
for recovering metals that requires low investment and operation costs. In this
work we studied the bioleaching of two kinds of acid-soluble copper sulfides,
one easily leached by mesophilic bacteria (covellite), and the other one
refractory to their activity (chalcopyrite), in acidic media with or without Fe2+
ions. We studied attached and planktonic populations of autotrophic bacteria,
such as Acidithiobacillus ferrooxidans,
Acidithiobacillus thiooxidans and Leptospirillum ferrooxidans in pure or
mixed cultures. The influence of a heterotrophic microorganism, Acidiphilium cryptum, was also studied. Attachment
was evaluated with fluorescence staining and FISH using four specific probes. L. ferrooxidans
showed highest initial attachment in all cases. The presence of Ap. cryptum increased the cell
attachment compared with the autotrophic pure cultures. It was possible to
correlate experimental data with a mechanism of bacterial-metal sulfide
oxidation, the polysulfide pathway for acid- soluble metal sulfides.