Molecular and Morphological Characterization of extremophilic Cultures from Copahue Volcano (Argentina)

GIAVENO A., HUERGO J. , LAVALLE L., SAND W. AND DONATI E.

Rosario Argentina

Congreso; 10mo Congreso Interamericano de Microscopía Electrónica (CIASEM2009) y 1er. Congreso de la Asociación Argentina de Microscopía (SAMIC 2009).; 2009

Asociación Argentina de Microscopía SAMIC

Abstract  Copahue Volcano is located at Neuquén province, Argentina. It has an acidic crater lake (pH ~ 0.2-1.1) and acid hot springs (pH ~ 0.3-2.5) near the summit that feed an acid river, the Río Agrio. Brown-reddish ferric and sulphur deposits have been observed on the banks of most of the streams and rivulets of the system. This zone is an important source of microorganisms of relevance for the conversion of an insoluble metal compound into a water soluble form, process known as bioleaching. Samples were taken from three different natural muddy fonts and they were cultured in order to obtain microbial communities with iron oxidative capacity. All cultures were able to grow on a mineral concentrate from Andacollo (Neuquén) containing pyrite and 71.1 g/t gold. The aim of this work was to characterize those microbial communities using different microscopic techniques. Scanning electron microscopy (SEM) and Atomic Force Microscopy (AFM) were performed over planktonic cells and attached cells to pyrite grains and coupons. In order to identify different species of mining bacteria, Fluorescent in situ Hybridization (FISH) with different probes and an epifluorescence microscope (EFM) was used. Bacteria and fungal cells were detected growing together on the pyrite.