Microorganisms bioleaching

Bosecker, K. Bioleaching Metal solubilization by microorganisms. Ferns Microbiol. Rev. 1997, 20, 591-604. 

Biosorption/bioleaching and oxidation/reduction mediated by other elements oxidized or reduced by microorganisms... 

Bosecker K (1997) Bioleaching metal solubilization by microorganisms. FEMS Microbiol Rev 20 591-604... 

Bioleaching processes use microorganisms to solubilize heavy metals or heavy-metal oxides from mineral matrices by biological catalyzed oxidation-rednction processes. In both soil washing or bioleaching processes, the elnted heavy metal ions are then removed from the aqueous stream by the various chemical or biological process technologies (see details in Rorrer, 1999). 

The US Environmental Protection Agency s Toxics Release Inventory Program of reported releases documented a total release of 24.5 X lO pounds (11 x 10 kg) of Al fume or dust in 2000 (US EPA 2002a). Considerable effort has been devoted toivard Al recovery from ivaste generated by its production and from coal-fired poiver stations. Bioleaching Al from industrial ivaste by microorganisms has also been demonstrated (Bojinova and Velkova 2001). 

In bioleaching, many types of microorganisms, including bacteria and fungi, are employed. In order to classify the biology involved in bioleaching, the reactions involved are addressed as direct and indirect. These major mechanisms can be briefly defined as follows ... 

D. Pradhan, S. Pal, L.B. Sukla, G. Roy Chaudhury, T. Das. Bioleaching of low-grade copper ore using indigenous microorganisms. Indian Journal of Chemical Technology, Vol. 15, pp. 588-592, November 2008. 

EPSs may also contribute to the provision of reduced oxygen tension and participate in the uptake of metal ions. Acidithiobacillusferrooxidans is one of the most commonly used microorganisms in bioleaching. Once cells have attached to the mineral, an EPS layer is developed over the next few days, creating the contact between bacterial cells and the sulfidic energy source. 

J. Lee, S. Acar, D.L. Doerr and J.A. Brierley (2011) Hydrometallurgy, vol. 105, p. 213 - Comparative bioleaching and mineralogy of composited sulfide ores containing aiargite, covellite and chalcocite by mesophUic and thermophilic microorganisms . 

Bioleaching is an application of mineral alteration under the action of microorganisms. The combination of molecular biology, reflectance microscopy, and XPS demonstrated that reduction of Fe ) oxides under the influence of Geobacter sul-furreducens could be related to the expression of specific genes by individual bacterial cells and cell aggregates associated with the mineral surface. Mineral transformation by G. pelophilus was also demonstrated to be mediated by the surface asso-... 

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