75 research outputs found

    Solar drying in the vineyard: a sustainable technology for the recovery of nutrients from winery organic waste

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    The present study describes a pilot-scale experimental validation of a forced-convection greenhouse solar dryer, combined with a biofilter, for controlled atmospheric emissions. This set-up was applied to the dewatering of sewage sludge from a biological plant that treated process wastewater in a commercial Mediterranean winery. Experiments were performed after the harvest, from September onwards, during the peak generation of sludge. The average drying rate during the first 10 days of operation ranged from 1.17 to 2.24 kg m−2 d−1, depending on the measurement method, during which the water content of the sludge was reduced from 90% down to 67%. Biofiltration was quite inefficient against greenhouse gases (methane and dinitrous oxide), and direct emissions during the drying process were on average 57 g CO2-eq m−2 d−1. Ammonia and volatile organic compounds were removed with average efficiencies of 71% and 35%, but ammonia losses through volatilization represented less than 2% of the initial nitrogen content. The sludge was dried further during November, to the lowest possible water content of 14%. Both the intermediate and final sludge dried materials were characterized for their agronomical value as organic fertilizers.info:eu-repo/semantics/acceptedVersio

    Functional biodiversity and plasticity of methanogenic biomass from a full-scale mesophilic anaerobic digester treating nitrogen-rich agricultural wastes

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    The effect of ammonia on methanogenic biomass from a full-scale agricultural digester treating nitrogen-rich materials was characterized in batch activity assays subjected to increasing concentrations of total ammonia N. Acetotrophic and methanogenic profiles displayed prolonged lag phases and reduced specific activity rates at 6.0 gN-TAN L−1, though identical methane yields were ultimately reached. These results agreed with the expression levels of selected genes from bacteria and methanogenic archaea (qPCR of 16S rRNA and mrcA cDNA transcripts). Compound-specific isotope analysis of biogas indicated that ammonia exposure was associated to a transition in methanogenic activity from acetotrophy at 1.0 gN-TAN L−1 to intermediate and complete hydrogenotrophy at 3.5 and 6.0 gN-TAN L−1. Such pattern matched the results of 16S-Illumina sequencing of genes and transcripts in that predominant methanogens shifted, along with increasing ammonia, from the obligate acetotroph Methanosaeta to the hydrogenotrophic Methanoculleus and the poorly understood methylotrophic Methanomassiliicoccus. The underlying bacterial community structure remained rather stable but, at 6.0 gN-TAN L−1, the expression level increased considerably for a number of ribotypes that are related to potentially syntrophic genera (e.g. Clostridium, Bellilinea, Longilinea, and Bacteroides). The predominance of hydrogenotrophy at high ammonia levels clearly points to the occurrence of the syntrophic acetate oxidation (SAO), but known SAO bacteria were only found in very low numbers. The potential role of the identified bacterial and archaeal taxa with a view on SAO and on stability of the anaerobic digestion process under ammonia stress has been discussed.info:eu-repo/semantics/acceptedVersio

    Environmental isolation of black yeast-like fungi involved in human infection

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    The present study focuses on potential agents of chromoblastomycosis and other endemic diseases in the state of Paraná, Southern Brazil. Using a highly selective protocol for chaetothyrialean black yeasts and relatives, environmental samples from the living area of symptomatic patients were analysed. Additional strains were isolated from creosote-treated wood and hydrocarbon-polluted environments, as such polluted sites have been supposed to enhance black yeast prevalence. Isolates showed morphologies compatible with the traditional etiological agents of chromoblastomycosis, e.g. Fonsecaea pedrosoi and Phialophora verrucosa, and of agents of subcutaneous or systemic infections like Cladophialophora bantiana and Exophiala jeanselmei. Some agents of mild disease were indeed encountered. However, molecular analysis proved that most environmental strains differed from known etiologic agents of pronounced disease syndromes: they belonged to the same order, but mostly were undescribed species. Agents of chromoblastomycosis and systemic disease thus far are prevalent on the human host. The hydrocarbon-polluted environments yielded yet another spectrum of chaetothyrialean fungi. These observations are of great relevance because they allow us to distinguish between categories of opportunists, indicating possible differences in pathogenicity and virulence

    Genomic Understanding of an Infectious Brain Disease from the Desert

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    Rhinocladiella mackenziei accounts for the majority of fungal brain infections in the Middle East, and is restricted to the arid climate zone between Saudi Arabia and Pakistan. Neurotropic dissemination caused by this fungus has been reported in immunocompromised, but also immunocompetent individuals. If untreated, the infection is fatal. Outside of humans, the environmental niche of R. mackenziei is unknown, and the fungus has been only cultured from brain biopsies. In this paper, we describe the whole-genome resequencing of two R. mackenziei strains from patients in Saudi Arabia and Qatar. We assessed intraspecies variation and genetic signatures to uncover the genomic basis of the pathogenesis, and potential niche adaptations. We found that the duplicated genes (paralogs) are more susceptible to accumulating significant mutations. Comparative genomics with other filamentous ascomycetes revealed a diverse arsenal of genes likely engaged in pathogenicity, such as the degradation of aromatic compounds and iron acquisition. In addition, intracellular accumulation of trehalose and choline suggests possible adaptations to the conditions of an arid climate region. Specifically, protein family contractions were found, including short-chain dehydrogenase/reductase SDR, the cytochrome P450 (CYP) (E-class), and the G-protein b WD-40 repeat. Gene composition and metabolic potential indicate extremotolerance and hydrocarbon assimilation, suggesting a possible environmental habitat of oil-polluted desert soilinfo:eu-repo/semantics/publishedVersio

    Tratamiento de la tuberculosis pulmonar

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    El tratamiento de la tuberculosis es importante tanto para preservar la salud del paciente como para prevenir la propagación de la enfermedad entre la población. Sus bases bacteriológicas estriban en el elevado número de bacilos que existen en la mayor parte de lesiones humanas de la TB y en la capacidad de mutar que tiene el M. tuberculosis cuando alcanza un número elevado de divisiones; ello hace imprescindible la asociación de fármacos que eviten la selección de mutantes resistentes. En nuestro medio la terapia farmacológica que se ha demostrado más eficaz consiste en la asociación durante dos meses de isoniacida, rifampicina y piracinamida seguida durante cuatro meses más con los dos primeros fármacos. En general los tuberculostáticos de primera elección son bien tolerados, pero pueden producir efectos secundarios potencialmente graves que conviene conocer y saber manejar. En el presente trabajo describimos también cómo se debe actuar desde el punto de vista terapéutico ante determinadas situaciones especiales y cuando los tratamientos iniciales se han abandonado o han fracasado. En los últimos cinco años en Navarra, se ha incrementado de forma importante la presencia de inmigrantes procedentes de países en vías de desarrollo con altas tasas de tuberculosis y de resistencias primarias. Este colectivo genera con frecuencia, como consecuencia de sus particulares condiciones socioeconómicas y su idiosincrasia cultural, dificultades respecto al cumplimiento del tratamiento, así como en los seguimientos y controles. El tratamiento de la tuberculosis siempre debe ser realizado por médicos expertos en el tema

    Influence of synthetic packing materials on the gas dispersion and biodegradation kinetics in fungal air biofilters

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    The biodegradation of toluene was studied in two lab-scale air biofilters operated in parallel, packed respectively with perlite granules (PEG) and polyurethane foam cubes (PUC) and inoculated with the same toluene-degrading fungus. Differences on the material pore size, from micrometres in PEG to millimetres in PUC, were responsible for distinct biomass growth patterns. A compact biofilm was formed around PEG, being the interstitial spaces progressively filled with biomass. Microbial growth concentrated at the core of PUC and the excess of biomass was washed-off, remaining the gas pressure drop comparatively low. Air dispersion in the bed was characterised by tracer studies and modelled as a series of completely stirred tanks (CSTR). The obtained number of CSTR (n) in the PEG packing increased from 33 to 86 along with the applied gas flow (equivalent to empty bed retention times from 48 to 12 s) and with operation time (up to 6 months). In the PUC bed, n varied between 9 and 13, indicating that a stronger and steadier gas dispersion was achieved. Michaelis-Menten half saturation constant (km) estimates ranged 71-113 mg m-3, depending on the experimental conditions, but such differences were not significant at a 95% confidence interval. The maximum volumetric elimination rate (rm) varied from 23 to 50 g m -3 h-1. Comparison between volumetric and biomass specific biodegradation activities indicated that toluene mass transfer was slower with PEG than with PUC as a consequence of a smaller biofilm surface and to the presence of larger zones of stagnant air. © 2008 Springer-Verlag. Chemicals / CAS: polyurethan foam, 9009-54-5; toluene, 108-88-3; Air Pollutants; Aluminum Oxide, 1344-28-1; Gases; Perlite, 12427-27-9; polyurethane foam, 9009-54-5; Polyurethanes; Silicon Dioxide, 7631-86-9; Toluene, 108-88-
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