Gombined use of two bioreactors in bioleaching of a copper sulphide ore

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 Exacta

Extremophilic Patagonian Microorganisms Working in Biomining

The microorganisms known as extremophiles have become a powerful tool in the field of biotechnology. Among them, acidophilic and thermophilic microorganisms capable of oxidizing iron(II) or sulfur compounds are very important in ore-processing operations as they are able to enhance the dissolution of sulfide ores. The aim of this chapter is to describe the physiological and phylogenetic characteristics of the main acidophilic species and communities found in geothermal and mining environments in Neuquen Province, Patagonia Argentina, and the advances done by our research group in their application to biomining and bioremediation of heavy metals. Additionally, the chapter includes the description of a novel thermoacidophilic archaeon from the genus Acidianus (Acidianus copahuensis) autochthonous of the Copahue geothermal area isolated and characterized by our research group.Centro de Investigación y Desarrollo en Fermentaciones IndustrialesUniversidad Nacional del Comahu

Circulating miR-26b-5p and miR-451a as diagnostic biomarkers in medullary thyroid carcinoma patients

Purpose/methodsThe determination of tumour biomarkers is paramount to advancing personalized medicine, more so in rare tumours like medullary thyroid carcinoma (MTC), whose diagnosis is still challenging. The aim of this study was to identify non-invasive circulating biomarkers in MTC. To achieve this goal, paired MTC tissue and plasma extracellular vesicle samples were collected from multiple centres and microRNA (miRNA) expression levels were evaluated.ResultsThe samples from a discovery cohort of 23 MTC patients were analysed using miRNA arrays. Lasso logistic regression analysis resulted in the identification of a set of circulating miRNAs as diagnostic biomarkers. Among them, miR-26b-5p and miR-451a, were highly expressed and their expression decreased during follow-up in disease-free patients in the discovery cohort. Circulating miR-26b-5p and miR-451a were validated using droplet digital PCR in a second independent cohort of 12 MTC patients.ConclusionThis study allowed the identification and validation of a signature of two circulating miRNAs, miR-26b-5p and miR-451a, in two independent cohorts reporting a significant diagnostic performance for MTC. The results of this study offer advancements in molecular diagnosis of MTC proposing a novel non-invasive tool to use in precision medicine

Microbial life in volcanic lakes

Lakes in the craters of active volcanoes and their related streams are often characterised by conditions considered extreme for life, such as high temperatures, low pH and very high concentrations of dissolved metals and minerals. Such lakes tend to be transient features whose geochemistry can change markedly over short time periods. They might also vanish completely during eruption episodes or by drainage through the crater wall or floor. These lakes and their effluent streams and springs host taxonomically and metabolically diverse microorganisms belonging in the Archaea, Bacteria, and Eucarya. In volcanic ecosystems the relation between geosphere and biosphere is particularly tight; microbial community diversity is shaped by the geochemical parameters of the lake, and by the activities of microbes interacting with the water and sediments. Sampling these lakes is often challenging, and few have even been sampled once, especially in a microbiological context. Developments in high-throughput cultivation procedures, single-cell selection techniques, and massive increases in DNA sequencing throughput, should encourage efforts to define which microbes inhabit these features and how they interact with each other and the volcano. The study of microbial communities in volcanic lake systems sheds light on possible origins of life on early Earth. Other potential outcomes include the development of microbial inocula to promote plant growth in altered or degraded soils, bioremediation of contaminated waste or land, and the discovery of enzymes or other proteins industrial or medical applications