Aplicaciones biotecnológicas de extremófilos provenientes de áreas geotermales
Biotechnological applications of extremophiles from geothermal areas
Geothermal areas are ecosystems inhabited by unique populations of microorganisms. Our research team investigated the microbial communities in different extreme environments including geothermal zones. Some of these areas showed high concentrations of certain metals and it was expected that microorganisms that thrive in such harsh environmental conditions have poly-resistance mechanisms. Strategies used by these microorganisms exhibiting tolerance or resistance to metals could constitute the basis for using such biota in different biotechnological applications that may have to deal with high metal content. Interactions metal-microorganisms is limited exclusively to mobilization, immobilization, and/or redox-mediated transformation of the metallic species. Microbial metal mobilization can be used to release (and eventually recover) metals from low-grade mineral ores, solid wastes, ashes, sludge, and even exhausted materials among others. Alternatively, metals can be immobilized in order to detoxify polluted water via mechanisms that are similar to those used to mobilize metals (pH and Eh changes plus complexation) but producing the opposite effect (i. e., immobilization). Furthermore, accumulation in the microbial cells, adsorption (enzymically mediated or passive) onto the microbial surface, and precipitation through combination with specific metabolites released into the environment can also produce an immobilization of the metals. Finally, changes in the oxidation state of metals catalyzed by microorganisms not only can lead to modifications in the solubility facilitating the mobilization or immobilization but also can produce fewer toxic metallic species. In this presentation results on metal tolerance of microbial consortia from geothermal zones in Argentina, the characteristics of some microorganisms isolated there and their applications in bioremediation and waste treatment will be discussed.