Papers by Author: A. García-Moyano

Abstract: Rio Tinto, a natural extreme acidic environment with a rather constant acidic pH and a high concentration of heavy metals, is the product of the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyritic Belt. Up to now the microbial characterization has been made mainly in the water column and biofilm samples. Since all ferric reducing activities will not benefit the bioleaching operations, we consider it critical to ascertain the ecology and metabolic properties of the microorganisms inhabiting the anoxic part of the sediments, to facilitate the design and control the operation of heap bioleaching processes, maximizing their efficiency. The implication of these microorganisms in biohydrometallurgical operations is discussed.

Abstract: Rio Tinto (Iberian Pyritic Belt, SW Spain) is a natural extreme acidic environment with a rather constant acidic pH (mean pH value 2.3) and a high concentration of heavy metals. The Tinto ecosystem is under the control of iron. The geomicrobiological characterization of Río Tinto has unravelled some basic questions of biohydrometallurgical interest. The methodologies developed for this study were applied successfully to monitor different bioleaching processes of the BioMinE project.

Abstract: Members of Leptospirillum genus have emerged not only as one of the most representative bacteria in the Río Tinto ecosystem, but also in other acidic environments (AMD), and in biohydrometallurgical operations. The main objective of this work was to study the role of chemolithoautotrophic bacteria of the genus Leptospirillum in the Río Tinto iron cycle (an extreme acidic environment, characterized by its constant low pH) to better understand and control industrial biohydrometallurgical processes. Different strains of Leptospirillum were isolated from the Río Tinto basin and physiologically and genetically characterized. Certain metabolic capabilities, such as pyrite leaching, iron oxidation and nitrogen fixation, were determined for each strain. Complementary molecular ecology techniques (FISH, CARD-FISH and cloning) were used to study the microbial diversity and the distribution of leptospirilli along the iron gradient in the different phases of Río Tinto: water column, anaerobic sediments and biofilms.