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Members of the genus Acidithiobacillus, now ranked within the class Acidithiobacillia, are model bacteria for the study of chemolithotrophic energy conversion under extreme conditions. Knowledge of the genomic and taxonomic diversity of Acidithiobacillia is still limited. Here, we present a systematic analysis of nearly 100 genomes from the class sampled from a wide range of habitats. Some of these genomes are new and others have been reclassified on the basis of advanced genomic analysis, thus defining 19 Acidithiobacillia lineages ranking at different taxonomic levels. This work provides the most comprehensive classification and pangenomic analysis of this deep-branching class of Proteobacteria to date. The phylogenomic framework obtained illuminates not only the evolutionary past of this lineage, but also the molecular evolution of relevant aerobic respiratory proteins, namely the cytochrome bo3 ubiquinol oxidases.

Copahue Thermal Center is characterized by the presence of mineromedicinal acidic waters with high temperatures, therapeutic peloids, and relevant consortia of extremophiles species, distributed in small natural pools which cannot be disinfected. The objective of this research was to investigate the survival of SARS-CoV-2 in Copahue’s waters and its remaining infective capacity. In a first assay, a decrease of more than 50% of the initially viral load compared to the initially inoculated positive sample was detected for all the water samples analyzed. After that, two of the Copahue springs, which are used as an immersion bath in closed environments without going through any disinfection treatment, was selected to determine the viral viability. VERO cell infections were performed, with no cytopathic effect detected, but a strikingly high resistance of the virus, detecting its genome by real time PCR, during the seven days of study under laboratory conditions. SARS-CoV-2 survival in acid media was reaffirmed, which is a peculiarity for a covered virus. A decrease in the detectable viral load of the positive sample was found as the infection time passed, becoming completely negative in the subsequent blind passages. More research is needed to further study the feasibility of SARS-CoV-2 in mineromedicinal waters, especially natural acidic waters that cannot disinfected, in order to expand information about the risk to populations that are exposed to them. Fil: Vela, María Lorena. Universidad Nacional del Comahue. Facultad de Ciencias de la Salud y del Ambiente; Argentina. Fil: Vela, María Lorena. Organización Térmica Provincial de Neuquén. E.Pro.Te.N.; Argentina. Fil: Masachessi, Gisela. Universidad Nacional de Córdoba. Facultad de Ciencias de la Salud; Argentina. Fil: Masachessi, Gisela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Giaveno, María Alejandra. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Fil: Giaveno, María Alejandra. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Roca Jalil, Maria Eugenia. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Fil: Roca Jalil, Maria Eugenia. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fil: Castro, Gonzalo. Ministerio de Salud de la Provincia de Córdoba. Departamento de Laboratorio Central; Argentina. Fil: Cachi, Ariana Mariela. Instituto Nacional de Medicina Aeronáutica y Espacial; Argentina. Fil: Cachi, Ariana Mariela. Universidad de la Defensa Nacional. Facultad de la Fuerza Aérea; Argentina. Fil: Marinzalda, María de los Ángeles. Instituto Nacional de Medicina Aeronáutica y Espacial; Argentina. Fil: Marinzalda, María de los Ángeles. Universidad de la Defensa Nacional. Facultad de la Fuerza Aérea; Argentina. Fil: Zugarramurdi, Ana. Organización Térmica Provincial de Neuquén E.Pro.Te.N; Argentina. Fil: Baschini, Miria. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Fil: Baschini, Miria. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.

Debido a la creciente actividad industrial en la provincia de Neuquén, Argentina; relacionada principalmente a la extracción de gas y petróleo, se han establecido diferentes empresas que ofrecen servicios afines a ésta actividad. En éste caso, se ha trabajado con la industria del recubrimiento metálico, la que por medio del proceso de niquelado de piezas, también conocido como niquelado electroless, imparte a los materiales mayor resistencia a la corrosión y dureza, aumentando así la vida útil de las herramientas y accesorios de perforación. Los residuos generados durante el proceso de recubrimiento de piezas contienen grandes volúmenes de soluciones con elevados niveles de níquel, altamente nocivo para la salud y el ambiente, con lo cual es primordial el desarrollo de técnicas de remoción del metal del medio acuoso para evitar que las soluciones de níquel, si fueran descartadas al ambiente, contaminen los cursos fluviales, haciendo de éstos un medio de transporte y en consecuencia, se transforme en una fuente de contaminación. La propuesta que se presenta a continuación abarca el empleo de técnicas de precipitación del metal, y el posterior tratamiento de las soluciones residuales resultantes, por adsorción y biosorción. Para el tratamiento por precipitación química se utilizó como reactivo precipitante N2H4 y, si bien el tratamiento propuesto remueve más del 99 % del níquel en solución, las cantidades de éste metal continúan siendo superiores a lo establecido por la normativa provincial ambiental vigente, la que indica hasta 3 mg.L-1 de níquel en aguas de descargas [1]. Por lo expuesto, es necesarios un segundo tratamiento de la solución sobrenadante, proponiendo en éste caso la adsorción del metal empleando como adsorbente un material arcilloso de descarte de la industria minera y, biosorción utilizando como biosorbente la biomasa descartada por la industria cervecera. El residuo con un contenido inicial de 8360 mg.L-1 de níquel fue reducido a 30 mg.L-1 luego de la precipitación química. A partir de la solución resultante, se inició el segundo tratamiento, en el cual se emplearon diferentes relaciones arcilla/sobrenadante y biomasa/sobrenadante, disminuyendo el contenido de níquel en la solución final a concentraciones en el equilibrio de 0,96 y 5,31 mg.L-1, respectivamente. Finalmente, se ha logrado la remoción del metal contaminante proveniente de la industria de niquelado químico al nivel permitido por la norma ambiental vigente, utilizando un tratamiento que combina tanto, técnicas de precipitación química, como adsorción y biosorción. Además, la importancia del presente trabajo, radica en el uso de materiales desechados de otras industrias, tales como la industria minera y la cervecera.

The discarded solutions by the chemical nickel industry have high amounts of nickel, this is why they are considered hazardous wastes for the health and the environment. On the other side, Ni particles can have potential applications in the developing of magnetorheological fluids currently being used to improve the performance of mechanical devices. The present study raises the treatment of a residual effluent from a chemical nickel industry by applying a chemical precipitation which uses sodium hypophosphite as a reducer, and varying the order of the reagents involved in the conditioning of the reaction with respect to the reducer. The recovered solids were studied using different material characterization techniques to recognize the chemical composition (X-Ray Fluorescence, Inductively Coupled Plasma Mass Spectrometry), crystallinity and morphology (X-Ray Diffraction, Scanning Electron Microscope), surface charge and size distribution (Dynamic Light Scattering). By the chemical reduction treatment it was possible to decrease the amount of nickel in the residual between 97.25% and 99.50%, obtaining Ni particles that were then tested to be used in magnetic fluids. To this purpose a suspension was prepared by mixing the Ni particles with silicone oil in a constant solid/liquid ratio, and the rheological behavior of this suspension was evaluated as a function of the magnetic field and the deformation applied, revealing an interesting magnetorheological behavior.

Nitrification is a key process for N-removal in engineered and natural environments, but recent findings of novel nitrifying microorganisms with surprising features revealed that our knowledge of this functional guild is still incomplete. Especially nitrite oxidation – the second step of nitrification – is catalyzed by a phylogenetically diverse bacterial group, and only recently bacteria of the phylum Chloroflexi have been identified as thermophilic nitrite-oxidizing bacteria (NOB). Among these, Nitrolancea hollandica was isolated from a laboratory-scale nitrifying bioreactor operated at 35°C with a high load of ammonium bicarbonate. However, its distribution remains cryptic as very few closely related environmental 16S rRNA gene sequences have been retrieved so far. In this study, we demonstrate how such thermophilic NOB can be enriched using modified mineral media inoculated with samples from a wastewater side-stream reactor operated at 39.5°C. Distinct cultivation conditions resulted in quick and reproducible high enrichment of two different strains of Nitrolancea, closely related to Nl. hollandica. The same cultivation approach was applied to a complex nitrite-oxidizing pre-enrichment at 42°C inoculated with biomass from a geothermal spring in the Copahue volcano area in Neuquen, Argentina. Here, an additional distinct representative of the genus Nitrolancea was obtained. This novel species had 16S rRNA and nitrite oxidoreductase alpha subunit (nxrA) gene sequence identities to Nl. hollandica of 98.5% and 97.2%, respectively. A genomic average nucleotide identity between the Argentinian strain and Nl. hollandica of 91.9% indicates that it indeed represents a distinct species. All Nitrolancea cultures formed lancet-shaped cells identical to Nl. hollandica and revealed similar physiological features, including the capability to grow at high nitrite concentrations. Growth was optimal at temperatures of 35–37°C and was strongly enhanced by ammonium supplementation. Genomic comparisons revealed that the four Nitrolancea strains share 2399 out of 3387 orthologous gene clusters and encode similar key functions. Our results define general growth conditions that enable the selective enrichment of Nitrolancea from artificial and natural environments. In most natural habitats these NOB apparently are of low abundance and their proliferation depends on the balanced presence of nitrite and ammonium, with an optimal incubation temperature of 37°C.

The Copahue volcano-R&iacute, o Agrio system, on Patagonia Argentina, comprises the naturally acidic river R&iacute, o Agrio, that runs from a few meters down the Copahue volcano crater to more than 40 km maintaining low pH waters, and the acidic lagoon that sporadically forms on the crater of the volcano, which is studied for the first time in this work. We used next-generation sequencing of the 16S rRNA gene of the entire prokaryotic community to study the biodiversity of this poorly explored extreme environment. The correlation of the operational taxonomic units (OTUs)s presence with physicochemical variables showed that the system contains three distinct environments: the crater lagoon, the Upper R&iacute, o Agrio, and the Salto del Agrio waterfall, a point located approximately 12 km down the origin of the river, after it emerges from the Caviahue lake. The prokaryotic community of the Copahue Volcano-R&iacute, o Agrio system is mainly formed by acidic bacteria and archaea, such as Acidithiobacillus, Ferroplasma, and Leptospirillum, which have been isolated from similar environments around the world. These results support the idea of a ubiquitous acidic biodiversity, however, this highly interesting extreme environment also has apparently autochthonous species such as Sulfuriferula, Acidianus copahuensis, and strains of Acidibacillus and Alicyclobacillus.

In this work we report the metagenome-derived draft genomic sequence of an enrichment culture dominated by A. ferrooxidans obtained from an airlift bioreactor inoculated with the microbial consortium recovered from the “Relave Viejo” tailing. The genome of this culture was assembled de-novo and by reference, generating a consensus assembly of 3.0 Mb. On the basis of 16S rRNA (100 % identity), average nucleotide identity analysis (99.33% identity) and in silico DNA-DNA hybridization against A. ferrooxidans ATCC 23270T (97.9%), the recovered genome is confirmed to pertain to A. ferrooxidans species. Comparative genomics results are presented to uncover the genetic traits of the variant surviving lime treatment and to further explore the genomic diversity of these model iron oxidizing species.

The geothermal Copahue-Caviahue (GCC) system (Argentina) is an extreme acidic environment, dominated by the activity of Copahue volcano. Environments characterised by low pH values, such as volcanic areas, are of particular interest for the search of acidophilic microorganisms with application in biotechnological processes. In this work, sulfate-reducing microorganisms were investigated in geothermal acidic, anaerobic zones from GCC system. Sediment samples from Agua del Limón (AL1), Las Máquinas (LMa2), Las Maquinitas (LMi) and Baño 9 (B9–2, B9–3) were found to be acidic (pH values 2.1–3.0) to moderate acidic (5.1–5.2), containing small total organic carbon values, and ferric iron precipitates. The organic electron donor added to the enrichment was completely oxidised to CO2. Bacteria related to ‘Desulfobacillus acidavidus’ strain CL4 were found to be dominant (67–83% of the total number of clones) in the enrichment cultures, and their presence was confirmed by their isolation on overlay plates. Other bacteria were also detected with lower abundance (6–20% of the total number of clones), with representatives of the genera Acidithiobacillus, Sulfobacillus, Alicyclobacillus and Athalassotoga/Mesoaciditoga. These enrichment and isolates found at low pH confirm the presence of anaerobic activities in the acidic sediments from the geothermal Copahue-Caviahue system. Fil: Willis, Graciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina Fil: Nancucheo, Ivan. Universidad San Sebastian.; Chile Fil: Hedrich, Sabrina. Federal Institute for Geosciences and Natural Resources; Alemania Fil: Giaveno, Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas. Universidad Nacional del Comahue. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina Fil: Johnson, David Barrie. Bangor University; Reino Unido

Thermophilic aerobic bacteria were isolated from two geothermal areas in Neuquén province using two different enrichment methods and a total of 30 isolates were obtained. From chicken feather enrichment cultures, strains affiliated to Bacillus cytotoxicus and Bacillus licheniformis were isolated and all of them demonstrated the capability to degrade completely chicken feather. A preliminary research on biotechnological enzymes’ potential demonstrated that all the isolates displayed at least one of the extracellular hydrolytic enzymes tested. Most of the isolates showed protease, inulinase and/or pectinase activities, while cellulase and xylanase activities were less common. In light of these findings, geothermal areas of Argentina may be considered as a potential source of thermophilic bacteria able to produce many industrially relevant enzymes., Facultad de Ciencias Exactas, Centro de Investigación y Desarrollo en Fermentaciones Industriales

In this study, Acidianus spp., a thermophilic archae which can oxidize sulphide minerals was used to produce ferric sulphate solutions from pyrite. The ferric sulphate solutions were aged through a forced hydrolysis process at different pH conditions to yield a variety of iron oxide and basic sulphate precipitates which were subsequently characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and Branauer–Emmett–Teller (BET) analysis. The results showed that potassium jarosite was formed as the main phase when ageing was done under acidic conditions. Various other iron oxides and oxyhydroxides were precipitated when ageing was done under neutral to basic pH conditions. For example, maghemite was precipitated as the main phase at a pH of 6–7, and magnetite was the main phase from a pH of 7–9. The spherical globular aggregates of magnetite nanoparticles formed were of high purity and had a surface area of 20.77 m2/g. Hematite nanoparticles were then produced via an oxidative transformation of the precursor magnetite nanoparticles at 600 °C. Since various precipitates were formed under different pH conditions, this knowledge can be used to control the solubility of the ferric ion in bioleaching and other industrial systems where iron removal is problematic.

The extremely thermophilic archaea have become a research hotspot in the recent years because of their extreme living conditions, physicochemical characteristics such as the oxidation of sulphur, metal sulphide ore and excellent leaching capability of metal sulphides. A novel thermoacidophilic archaea (ALE1 strain) of the genusAcidianus,CandidatusAcidianus copahuensis, was isolated from the Copahue Volcano area, in Neuquén, Argentina. This strain was able to metabolize different sulphur compounds under aerobic and anaerobic conditions. ALE1 strain was inoculated in M88, a selective medium for thermoacidophilic archaea recommended by DSMZ. Elemental sulphur (So) and potassium tetrathionate (T) were used alternatively as the energy source, while oxygen and iron (III) were the electron acceptors in the aerobic and anaerobic tests respectively. All systems were incubated at 70oC in shake flasks. The pH, Eh, [H+] and cell concentration were measured. The results from the aerobic test confirm that ALE1 strain was able to oxidize (So) and (T) decreasing the pH significantly, reaching the values 1 and 1.5, respectively. A light yellow precipitate was formed only in the inoculated systems in presence of (T). It was characterized by SEM and FTIR techniques showing that only sulphur atoms are bonded together in some way not confirmed yet. In the anaerobic tests, it was found that ALE1 was able to oxidize sulphur and tetrathionate ion transferring electrons to iron (III) acceptor. The Eh decreased in all inoculated systems from nearly 500mV to 300mV approximately. This work shows that ALE1 strain is helping to keep active the sulphur cycle in the Copahue volcanic environment; however the challenge is to elucidate the metabolism involved.

800x600 Mining waste disposal and treatment is one of the biggest environmental challenges that mining confront at present. A promising approach is the phytoremediation technology, where living plants are used to remove metals from impacted sites or to stabilize mine tailings. The aim of this work was to evaluate several plant species for phytoremediation of a mining waste from gold ores concentration plant in Andacollo, Neuquén-Argentina, to propose the execution of an environmental restoration plan in this area. For the forestation assays Pinus ponderosa, Pinus murrayana, Populus nigra species and a herbaceous plant, Festuca arundinacea, were selected. The tailings used in this study was physicochemically characterized and resulted to be non-potentially acid generating and presented very low organic matter and macronutrients contents. The sequential extraction showed that no metals were present in the water soluble fraction minimizing the risks of spreading heavy metals. Phytoremediation assay showed that all vegetable species could grow on the mine tailing. The dry vegetal biomass for F. arundinacea was only 28 % lower than the one obtained in the control soil. Pinus species and P. nigra presented high values of translocation factor only for Zn. These preliminary results suggest that the forestation of this tailing dam with Pinus species and F. arundinacea could be an adequate strategy to phytoremediate this particular area. Normal 0 21 false false false ES-AR X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";}

Assessing microbial communities in extreme environments allows the search for novel extremophilic microorganisms that can be of use in the development or improvement of biotechnological processes. Most microbial communities developed in such harsh environments have different heavy metal resistance strategies of importance in some technological applications as biomining but also in the bioremediation of metal-polluted environments. In this chapter we describe the microbial diversity of an acidic, volcanic geothermal environment in Northern Patagonia of Argentina: the Copahue geothermal system, containing different geothermal manifestations with temperatures up to 90 °C and pH values from 2 to 7 under aerobic and anaerobic conditions, provoking an enormous biodiversity. In addition, we report some heavy metal applications of those communities, focusing mainly in the bioprecipitation of heavy metals using sulfate-reducing microorganisms.

Dissolution of a natural troilite by thermophilic consortia collected from two hot springs placed in Copahue geothermal region (Neuquen — Argentina) and later enriched in specific media for sulphur-oxidisers is reported in this paper. The enrichment was carried out at a temperature (65 °C) far away from those measured in the original hot springs (40.5 °C and 87 °C) in order to analyse the flexibility of the consortia to keep viability under other temperature conditions. Different microscopic techniques (SEM, TEM, fluorescence microscopy) allowed the partial characterisation of the cultures used as inocula in the bioleaching experiments. Results show that, as other metal sulphides, troilite dissolution can be strongly catalysed by sulphur (and iron) wild oxidising microorganisms present in the consortia from Copahue hot springs. According to our results, the addition of sulphur increased the bioleaching rate although the troilite dissolution is not limited by such addition because sulphur is in situ generated by chemical oxidation. Iron solubilised from troilite was partially precipitated mainly as jarosite. An additional and interesting result of our studies indicates that natural consortia can have a wide thermal flexibility and there are some strains among them – especially archaeas from Sulfolobales genus – that are able to survive at temperatures far away from the ones registered in the place where they were collected.

This work presents an overview of the physicochemical and biological studies focusing on acidophilic microorganisms carried out along Rio Agrio and in different hot springs belonging to the geothermal Copahue–Caviahue system (Neuquen Argentina). This extreme environment is characterized by wide ranges of temperature and pH ( Leptospirillum ferrooxidans , Acidithiobacillus ferrooxidans , Acidithiobacillus thiooxidans and Acidianus spp., among others, were successfully cultivated. Some physiological properties of the isolates and several biotechnological applications of them were studied and the main results are presented in this paper.

This work presents an overview of the physicochemical and biological studies carried out along Rio Agrio and in different hot springs belonging to the geothermal Copahue volcano system, in Neuquén Argentina. This is an extreme environment characterized by wide ranges of temperature, pH (

In this report we evaluate the oxidative capacity of native microorganisms from Copahue geothermal system applied to a gold concentrate (71.1 g/t) compared to that showed by some culture collection strains. The sulphide ore, in which gold is present as submicroscopic particles contained in a pyrite matrix, came from several reservoirs of polymetallic ores located in Neuquén, Patagonia Argentina. The ore was processed in Andacollo treatment plant for gold concentration. After biooxidation tests, the highest percentages of solubilised iron were reached in the inoculated system (100% mixed native cultures, 47.8% Leptospirillum ferrooxidans ATCC 29047 and 28.5% for Acidithiobacillus ferrooxidans DSM 11477) while in the sterile control it was only 8.8%. The gold recovery was 96.3% and 45.3% for the treated and untreated concentrate respectively.

This report describes the detection and identification of archaea in several sites located in the area of Copahue volcano, Neuquén province, Argentina by mean of different molecular techniques (PCR, DGGE, DNA sequencing and FISH). In order to study the archaea morphology, cultures were examined using different microscopic techniques (SEM, TEM, EFM and AFM). The corresponding archaea were identified as close relative or members of the genus Acidianus as well as other uncultured archaea clones showing a 93% of similarity to each others.

Two strains of Leptospirillum ferrooxidans were isolated from samples taken from La Silvita polymetallic sulphide mine, Neuquen, Argentina. Isolates were identified by 16S rRNA gene restriction enzyme analysis. The specific growth rate ( μ ) at different temperatures and pH values were examined. The potential of two isolates to assist the leaching process using a mineral ore from the same mine was evaluated. The tests were carried out in shake flask at 1% (w/v) pulp density. The main sulphides found in the mineralogical composition of La Silvita ore were: sphalerite, galena, pyrite and chalcopyrite. Zinc and copper recoveries with a native isolate were 100% in 20 days and 12 days, respectively. Iron solubilization was 42% after 33 days of operation. These values were greater than those obtained using a laboratory reference strain, L. ferrooxidans DSMZ 2705, or abiotic conditions.

Bioleaching of low-grade complex sulfide ores from La Silvita and La Resbalosa (Patagonia Argentina) were carried out in a reverse flow airlift reactor by a native strain of Leptospirillum ferrooxidans (Lf-LS04). The reactor was filled with iron free 9K medium pH 1.8, with mineral particle size of – 74 μm, pulp density of 1% and a superficial air velocity of 0.01m s − 1 . Zinc recoveries from the two sulfide ores – mainly in the case of La Silvita ore – were higher than those obtained previously with a collection strain of A. ferrooxidans . By applying the shrinking core-product layer diffusion model to sphalerite leaching, diffusion was found to be rate limiting due to the formation of an insoluble product layer (elemental sulfur, anglesite and ferric iron precipitates) as well as to the presence of an unreacted layer of gangue minerals (quartz, feldspar). Even in this case, the indigenous strain of L. ferrooxidans was shown to be highly efficient for processing both complex sulfides in the absence of sulfur-oxidizing bacteria.

Bioleaching of a sulfide ore was investigated using a consortium of thermophilic bacteria and archaea. The consortium was obtained through successive enrichment procedures (using M88 with tetrathionate) after isolating from two different places into the geothermal area (Baño 9 and Las Maquinitas) of the Copahue volcano (in the north of Neuquén province in Argentina). Bioleaching experiments were carried out in 250-ml shake flasks with 100 ml of media and 1 g of the sulfide ore. Flasks were incubated at 150 rpm and 70 oC. The major constituents of the ore (La Resbalosa, Argentina) were sphalerite, pyrite, chalcopyrite and galena. The sample used throughout bioleaching experiments contained 22.5 % Zn. Two different media (0K and M88) were evaluated with and without the addition of elemental sulfur. Genetic diversity analysis of the microbial community was performed by PCR amplification of bacterial 16S rDNA fragments and analyzed by DGGE (denaturing gradient gel electrophoresis). The 16S rDNA was amplified by using eubacteria and archaea primers. Metal concentration, Eh and pH were periodically analyzed. Solid residues were filtered, washed, dried and finally analyzed by XRD and XRF. After 45 days, more than 50 % of zinc and about 100 % of the copper were solubilized. Galena and jarosite were detected in the solid residues. The data indicated that the dominant acidophiles were bacteria or archaea according to the media. M88 media allowed an important decrease of pH and higher zinc extractions while the presence of sulfur did not show significant influence on the zinc recovery.

The Copahue geothermal system is a natural extreme environment located at the northern end of the Cordillera de los Andes in Neuquén province in Argentina. The geochemistry and consequently the biodiversity of the area are dominated by the activity of the Copahue volcano. The main characteristic of Copahue is the extreme acidity of its aquatic environments; ponds and hot springs of moderate and high temperature as well as Río Agrio. In spite of being an apparently hostile location, the prokaryotic biodiversity detected by molecular ecology techniques as well as cultivation shows a rich and diverse environment dominated by acidophilic, sulphur oxidising bacteria or archaea, depending on the conditions of the particular niche studied. In microbial biofilms, found in the borders of the ponds where thermal activity is less intense, the species found are completely different, with a high presence of cyanobacteria and other photosynthetic species. Our results, collected during more than 10 years of work in Copahue, have enabled us to outline geomicrobiological models for the different environments found in the ponds and Río Agrio. Besides, Copahue seems to be the habitat of novel, not yet characterised autochthonous species, especially in the domain Archaea., This work was partially supported by grants PICT 2012-0623 and PICT 2013-0630 (ANPCYT)., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

Copahue is a natural geothermal field (Neuquén province, Argentina) dominated by the Copahue volcano. As a consequence of the sustained volcanic activity, Copahue presents many acidic pools, hot springs and solfataras with different temperature and pH conditions that influence their microbial diversity. The occurrence of microbial biofilms was observed on the surrounding rocks and the borders of the ponds, where water movements and thermal activity are less intense. Microbial biofilms are particular ecological niches within geothermal environments; they present different geochemical conditions from that found in the water of the ponds and hot springs which is reflected in different microbial community structure. The aim of this study is to compare microbial community diversity in the water of ponds and hot springs and in microbial biofilms in the Copahue geothermal field, with particular emphasis on Cyanobacteria and other photosynthetic species that have not been detected before in Copahue. In this study, we report the presence of Cyanobacteria, Chloroflexi and chloroplasts of eukaryotes in the microbial biofilms not detected in the water of the ponds. On the other hand, acidophilic bacteria, the predominant species in the water of moderate temperature ponds, are almost absent in the microbial biofilms in spite of having in some cases similar temperature conditions. Species affiliated with Sulfolobales in the Archaea domain are the predominant microorganism in high temperature ponds and were also detected in the microbial biofilms. Fil: Urbieta, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina Fil: Gonzalez Toril, Elena. Consejo Superior de Investigaciones Cientificas; España Fil: Aguilera Bazán, Ángeles. Consejo Superior de Investigaciones Cientificas; España Fil: Giaveno, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnol.conicet - Patagonia Norte. Instituto de Investigación y Des. En Ing. de Procesos, Biotecnología y Energias Alternativas. Idepa - Subsede San Antonio Oeste; Argentina Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

A modeling approach of the bacterial oxidation of ferrous iron in batch culture is presented. It is based on the spatial interpolation of experimental data known as kriging interpolation. It is shown that, using the proposed method, the prediction error between model and true system variables is optimal in the sense of minimum variance. The results obtained improve the prediction error associated to the use of the current “knowledge-based” models. Results on modeling the kinetics of the bacterium Acidithiobacillus ferrooxidans , previously called Thiobacillus ferrooxidans , growing in ferrous iron as energy source in a batch airlift reactor are presented. The prediction error bound associated with the model is deduced theoretically and calculated for the application case.

Copahue is an acidic geothermal volcanic region in the northwest corner of Neuquén Province, Argentina. In the area, there are various ponds, pools and hot springs with different temperatures, pH values and levels of anthropogenic influence. In this study, the prokaryotic biodiversity of five representative ponds was studied by using two complementary molecular ecology techniques: phylogenetic analysis of 16S rRNA bacterial and archaeal genes and FISH (or CARD-FISH) for quantitative estimation of biodiversity. The results, supported by multivariate statistical analysis, showed that the biodiversity in Copahue ponds seemed to be determined by temperature. High temperature ponds were dominated by archaea, mainly apparently novel representatives from the orders Sulfolobales and Thermoplasmatales that had no close cultivated relatives. By contrast, moderate temperature ponds were colonised by well-characterised sulphur-oxidising bacteria related to acidic environments, such as other geothermal sites or acid mine drainage, and archaea were absent. By combining the biodiversity results from this study and the reported physicochemical features of Copahue, a preliminary model of the possible biogeochemical interaction was outlined for moderate and high temperature ponds. Fil: Urbieta, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina Fil: Gonzalez Toril, Elena. Consejo Superior de Investigaciones Cientificas; España Fil: Giaveno Filippa, María Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Comahue; Argentina Fil: Aguilera Bazán, A. Consejo Superior de Investigaciones Cientificas; España Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales. Universidad Nacional de la Plata. Facultad de Cs.exactas. Centro de Investigación y Desarrollo En Fermentaciones Industriales; Argentina

Acidianus copahuensis is a recently characterized thermoacidophilic archaeon isolated from the Copahue volcanic area in Argentina. Here, we present its draft genome sequence, in which we found genes involved in key metabolic pathways for developing under Copahue's extreme environmental conditions, such as sulfur and iron oxidation, carbon fixation, and metal tolerance., Centro de Investigación y Desarrollo en Fermentaciones Industriales

Copahue is a geothermal field located in the Northwest corner of Neuquén province in Argentina. It is dominated by the still active Copahue volcano. In the area there are many acidic pools, hot springs and solfataras with different temperature and pH conditions that influence their microbial diversity. On the surrounding rocks and the borders of the pools, where water movements and thermal activity are less intense, many biofilms can be found. They have different aspects and structure, and they present less extreme temperature and pH conditions than the ponds and hot springs. Biofilms are a different ecological niche and they have different microbial community structure. In this study carried out by molecular ecology techniques, mainly 16S and 18S rRNA sequencing, we report a strong presence of cyanobacterias, cloroflexi and eukaryotes, not detected in previous biodiversity studies done on water samples. Almost no acidophilic bacteria were found, with the exception of members of genus Thiomonas, also found in the acidic pools. Archaea were detected only in one of the biofilms and the structure of that community seems to be similar to those found in water samples, with many uncultured species mainly related to order Sulfolobales. The aim of this study is to assess microbial community diversity in the biofilms present in this acidic geothermal area, with particular emphasis on detection of cyanobacterias and eukaryotes with potential biotechnological applications like production of alternative energy sources, synthesis and accumulation of biomolecules with antiviral or antibiotic activities or potential ability to bioremediate contaminated areas. Fil: Urbieta, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina Fil: González Toril, Elena. Instituto Nacional de Técnica Aeroespacial. Centro de Astrobiología; España Fil: Aguilera, Ángeles. Instituto Nacional de Técnica Aeroespacial. Centro de Astrobiología; España Fil: Giaveno, María Alejandra. Universidad Nacional del Comahue; Argentina Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Fermentaciones Industriales; Argentina

Microbial consortia taken from an extreme environment were grown at different temperatures and enrichment media. The consortia response to environmental changes was evaluated in order to investigate their metabolic flexibility. The molecular technique, DGGE (denaturing gel gradient electrophoresis) was carried out to evaluate the biodiversity. The results show that each consortium was able to grow according to the available resources, demonstrating their flexibility. A selective development was detected when growing conditions were similar to those found in the natural environment even though some species were able to grown even in conditions far away from those present in the sampling sites. Fil: Zurakoski, Natasha. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina Fil: Giaveno, María A.. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Ulloa, Ricardo J.. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Lavalle, Teresa Laura. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Urbieta, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales (i); Argentina Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales (i); Argentina

La biolixiviación de minerales sulfurados de baja ley, utilizando microorganismos mesófilos, es una vía alternativa económicamente viable para la recuperación de ciertos metales de bajo costo. Habitualmente, los procesos de biolixiviación se realizan con los microorganismos en contacto directo con el mineral, lo que ocasiona ciertos inconvenientes (depósitos sólidos sobre el mineral, toxicidad de los iones sobre las bacterias, etc.). Estos inconvenientes pueden superarse mediante el uso de una metodología indirecta, generando el medio lixiviante a través de biorreactores. Estos consisten, esencialmente, en soportes saturados de bacterias adheridas a través de los cuales se hace pasar medio fresco para generar el medio lixiviante deseado. En este trabajo, se propone una combinación de dos biorreactores: uno, utilizado previamente, que genera medio oxidante a través de la acción del Thiobacillus ferrooxidans, y otro, presentado aquí, generador de medio sulfúrico por acción del Thiobacillus thiooxidans. Este sistema combinado se ha utilizado para lixiviar un mineral sulfurado de cobre de baja ley, logrando una recuperación importante del metal. La incorporación del biorreactor generador de ácido sulfúrico permitió eliminar los inconvenientes provocados por los depósitos de jarosita sobre el mineral, a un valor de pH relativamente bajo, manteniendo una elevada concentración de oxidante (ion Fe (III)) durante todo el proceso., Bioleaching of sulphide ores using mesophiles microorganisms is an altemative way, economically viable, for certain inexpensive metáis recovery. Generally, in these processes some problems become from the direct contact of microorganisms with the ore (deposits, toxicity of ions on the bacteria, etc.). To prevent these troubles, an indirect methodology with the so called bioreactors to genérate the leaching médium may be used. These are supports saturated with attached bacteria through which fresh liquid médium is precolated to genérate the lixiviant solution. In this paper a two combined bioreactors system is proposed; one of them, previously used, generates oxidant médium through the use of Thiobacillus ferooxidans and other, introduced in this work, produces sulphuric acid médium using Thiobacillus thiooxidans. This combined system has been used to leach a copper sulphide mineral with an important recovery of the metal. The sulphuric acid producing bioreactor prevented troubles associated with jarosites deposits on the ore, which appear at low pH. At the same time a high concentration of oxidant agent (Fe(III) ion) is maintained during the process., Facultad de Ciencias Exactas

A novel thermoacidophilic archaeal strain has been isolated from three geothermal acidic hot springs in Copahue, Argentina. One of the most striking characteristic of ALE1 isolate is its metabolic versatility. It grows on sulphur, tetrathionate, iron (II) and sucrose under aerobic conditions, but it can also develop under anaerobic conditions using iron (III) or sulphur as electron acceptors and sulphur or hydrogen as electron donors autotrophically. A temperature of 75 °C and a pH between 2.5 and 3.0 are strain ALE1 optimal growth conditions, but it is able to oxidise iron (II) even at pH 1.0. Cells are irregular cocci surrounded by a regularly arrayed glycoprotein layer (S-layer). Phylogenetic analysis shows that strain ALE1 belongs to the family Sulfolobaceae in the class Thermoprotei, within the phylum Crenarchaeota. Based on 16S rRNA gene sequence similarity on NCBI database, ALE1 does not have closely related relatives, neither in culture nor uncultured, which is more surprising. Its closest related species are strains of Acidianus hospitalis (91 % of sequence similarity), Acidianus infernus (90 %), Acidianus ambivalens (90 %) and Acidianus manzanensis (90 %). Its DNA base composition of 34.5 %mol C+ G is higher than that reported for other Acidianus species. Considering physiological and phylogenetic characteristics of strain ALE1, we considered it to represent a novel species of the genus Acidianus (candidatus "Acidianus copahuensis"). The aim of this study is to physiologically characterise this novel archaea in order to understand its role in iron and sulphur geochemical cycles in the Copahue geothermal area and to evaluate its potential applications in bioleaching and biooxidation. Fil: Giaveno Filippa, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Urbieta, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo en Fermentaciones Industriales (i); Argentina Fil: Ulloa, José Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentina Fil: Toril, Elena. Instituto Nacional de Técnica Aeroespacial. Centro de Astrobiología; España Fil: Donati, Edgardo Ruben. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Centro de Investigación y Desarrollo En Fermentaciones Industriales (i); Argentina

Two acidic hot springs close to the crater of Copahue Volcano (Neuquen, Argentina) are the source of the Rio Agrio. The river runs several kilometres before flowing into Caviahue Lake. Along the river, temperature, iron, other metal and proton concentrations decrease gradually with distance downstream. From the source to the lake and depending on the season, pH can rise from 1.0 (or even less) to about 4.0, while temperature values decrease from 70°C to 15°C. Water samples were taken from different stations on the river selected according to their physicochemical parameters. In order to assess prokaryotic biodiversity throughout the water column, different and complementary molecular biology techniques were used, mainly in situ hybridisation and 16S rRNA gene cloning and sequencing. All microorganisms found are typical of acidic environments. Sulphur-oxidizing bacteria like Acidithiobacillus thiooxidans and Acidithiobacillus albertensis were detected in every station. Moderately thermophile iron- and sulphur-oxidizing bacteria like members of Alicyclobacillus and Sulfobacillus genera were also ubiquitous. Strict iron-oxidizing bacteria like Leptospirillum and Ferrimicrobium were present at the source of the river, but disappeared downstream where iron concentrations were much lower. Iron-oxidizing, mesophilic Ferroplasma spp. were the main archaea found. The data presented in this work represent the first molecular assessment of this rare natural acidic environment.

Over the last decade biooxidation for the pretreatment of refractory sulfidic gold concentrates and the bioleaching of copper have been applied with increasing frequency. In addition to heap-leach facilities for the bioleaching of copper, several biotank oxidation plants are also operational for the pretreatment stage in the processing of refractory gold ores in large-scale operations (Brierley, 1997; Acevedo, 2000; Rossi, 2001). The application of commercial biooxidation plants using bioreactors started in South Africa and expanded first into Africa and then Australia, South America and, more recently, into China (Morin et al., 2005). These commercial operations show that bioleaching/biooxidation processes can be viable options for the mining industry. Moreover, there is currently a great deal of interest in improving tank technologies for use in the recovery of other metals, such as Cu, Ni, Zn and Co (Brierley & Brierley, 1999; Okibe et al., 2003; Morin et al., 2005; Acevedo & Gentina, 2005; Sand & Gehrke, 2006). The reactors most commonly employed in biohydrometallurgy are the Stirred Tank Reactor (STR), the Bubble Column (BCR) and the Airlift Reactor (ALR). Additionally, cylindrical vessels with a conical bottom known as Pachuca tanks have traditionally been used in biomining. Furthermore, new reactor designs have recently been developed: the Low Energy Bioreactor, the Delft Inclined Plate Bioreactor and the Revolving Drum Bioreactor (Biorotor) (Rossi, 2001). Numerous different papers have been published on bioleaching-biooxidation processes using ALRs and Pachuca tanks (Atkins et al., 1986; Acevedo et al., 1987; Roy et al., 2000; Acevedo, 2000; Rossi, 2001; Mousavi et al., 2005; Shi & Fang, 2005); however, there is limited knowledge on the applications and characterization