ABSTRACT
BACKGROUND: Microalgae biomass is regarded as a potential feedstock for bioenergy purposes through anaerobic digestion (AD). Even though AD is a well-proven technology, the use of new feedstocks requires in-depth studies. A lot of research has been conducted assessing methane yield without paying attention to the anaerobic microbiome and their activities. For such a goal, the present investigation was designed to link methane yield to those two later sludge characteristics. In this sense, different anaerobic sources were tested, namely adapted to microalgae biomass and adapted to sewage sludge. RESULTS: Despite the registered differences for the anaerobic microbiome analysis and specific methane activities towards model substrates, sludge adapted to digest sewage sludge did not affect the methane yield of Chlorella sorokiniana and Scenedesmus sp. Opposite to that, sludge samples adapted to digest microalgae exhibited a concomitant increase in methane yield together with increasing digestion temperatures. More specifically, the values attained were 63.4 ± 1.5, 79.2 ± 3.1 and 108.2 ± 1.9 mL CH4 g COD in-1 for psychrophilic, mesophilic and thermophilic digestions, respectively. While psycro- and mesophilic digestion supported similar yields (most probably linked to their anaerobic microbiome resemblance), the values attained for thermophilic digestion evidenced the usefulness of having a highly specific microbiome. The relative abundance of Firmicutes, particularly Clostridia, and Proteobacteria together with an important abundance of hydrogenotrophic methanogens was highlighted in this inoculum. CONCLUSION: Overall, this study showed that working with tailored anaerobic microbiome could help avoiding pretreatments devoted to methane yield enhancement.
ABSTRACT
Biological desulfurization has proven to be a process that is technically and economically feasible on using biotrickling filters that can be performed under aerobic and anoxic conditions. However, microbial communities are different mainly due to the use of different final electron acceptors. The analysis of microbial communities in these systems has not been addressed with regard to the anoxic process. The aim of the work reported here was to analyse the eubacterial community in the two types of bioreactor along the packed bed and during the operation time. The analysis was carried out using the 16S PCR-DGGE molecular fingerprint technique. The microbial profile analysis in the aerobic bioreactor revealed that the community was more diverse and stratified compared to those obtained in the two anoxic bioreactors, influenced by environmental factors. The main OTU involved in this process is genus Thiobacillus, although different species were detected depending on each operational condition.
Subject(s)
Bioreactors/microbiology , DNA Fingerprinting , DNA, Bacterial/genetics , DNA, Ribosomal/genetics , Polymerase Chain Reaction , RNA, Ribosomal, 16S/genetics , Thiobacillus/geneticsABSTRACT
El presente trabajo muestra un estudio de 58 fuentes de acceso abierto correspondientes a 14 países de América Latina y el Caribe. Se busca identificar algunos problemas relacionados con la estandarización del protocolo OAI-PMH en los repositorios de acceso abierto en América Latina y el Caribe y cómo estos afectan la distribución de contenidos. El objetivo que el trabajo persigue es identificar las limitantes que afectan el intercambio de contenidos entre fuentes de acceso abierto en América Latina y el Caribe mediante el estudio de repositorios institucionales y de revistas de corte científico que hacen función de proveedores de datos. Las fuentes seleccionadas responden a revistas de corte científico y a repositorios de universidades. El estudio fue realizado con el empleo del software OHS (Open Harvester System) y tiene en cuenta aspectos como la tecnología empleada, los estándares de metadatos y la forma de representación de la información, además del uso de los verbos que establece el protocolo OAI-PMH. Se hizo una observación del funcionamiento de algunos repositorios de acceso abierto y se probaron las respuestas de estos ante las peticiones de los verbos. Los resultados obtenidos muestran diversidad, tanto tecnológica como en la forma de aplicar los estándares, y reflejan algunas de las problemáticas a las que se enfrenta el movimiento de acceso abierto en el área de estudio y cómo esto afecta la interoperabilidad necesaria para automatizar el intercambio de contenidos(AU)
A review was conducted of 58 open access sources from 14 Latin American and Caribbean countries, with the purpose of identifying problems related to the standardization of the OAI-PMH protocol in Latin American and Caribbean open access repositories, as well as the way in which these problems affect the distribution of contents. The study was aimed at identifying the limitations affecting the exchange of contents between Latin American and Caribbean open access sources through the study of institutional repositories and scientific journals which perform the function of data providers. The sources selected were scientific journals and university repositories. The study was based on the software OHS (Open Harvester System) and considered aspects such as the technology used, metadata standards and the manner in which information was represented, besides the verbs established by the OAI-PMH protocol. The functioning of some open access repositories was observed and tests were conducted of their response to the requests of verbs. Results show diversity both in the technology and in the way standards are applied, as well as some of the problems faced by the open access movement in the study area and their impact on the interoperability required to automate the exchange of contents(AU)
Subject(s)
Humans , Computer Communication Networks/standards , Reference Standards , Access to Information , Latin America/ethnology , Caribbean Region/ethnologyABSTRACT
El presente trabajo muestra un estudio de 58 fuentes de acceso abierto correspondientes a 14 países de América Latina y el Caribe. Se busca identificar algunos problemas relacionados con la estandarización del protocolo OAI-PMH en los repositorios de acceso abierto en América Latina y el Caribe y cómo estos afectan la distribución de contenidos. El objetivo que el trabajo persigue es identificar las limitantes que afectan el intercambio de contenidos entre fuentes de acceso abierto en América Latina y el Caribe mediante el estudio de repositorios institucionales y de revistas de corte científico que hacen función de proveedores de datos. Las fuentes seleccionadas responden a revistas de corte científico y a repositorios de universidades. El estudio fue realizado con el empleo del software OHS (Open Harvester System) y tiene en cuenta aspectos como la tecnología empleada, los estándares de metadatos y la forma de representación de la información, además del uso de los verbos que establece el protocolo OAI-PMH. Se hizo una observación del funcionamiento de algunos repositorios de acceso abierto y se probaron las respuestas de estos ante las peticiones de los verbos. Los resultados obtenidos muestran diversidad, tanto tecnológica como en la forma de aplicar los estándares, y reflejan algunas de las problemáticas a las que se enfrenta el movimiento de acceso abierto en el área de estudio y cómo esto afecta la interoperabilidad necesaria para automatizar el intercambio de contenidos.
A review was conducted of 58 open access sources from 14 Latin American and Caribbean countries, with the purpose of identifying problems related to the standardization of the OAI-PMH protocol in Latin American and Caribbean open access repositories, as well as the way in which these problems affect the distribution of contents. The study was aimed at identifying the limitations affecting the exchange of contents between Latin American and Caribbean open access sources through the study of institutional repositories and scientific journals which perform the function of data providers. The sources selected were scientific journals and university repositories. The study was based on the software OHS (Open Harvester System) and considered aspects such as the technology used, metadata standards and the manner in which information was represented, besides the verbs established by the OAI-PMH protocol. The functioning of some open access repositories was observed and tests were conducted of their response to the requests of verbs. Results show diversity both in the technology and in the way standards are applied, as well as some of the problems faced by the open access movement in the study area and their impact on the interoperability required to automate the exchange of contents.
ABSTRACT
Se trata de un paciente masculino de 57 años, con antecedentes patológicos personales de ser fumador y de padecer alcoholismo, hipertensión arterial, miocardiopatía dilatada y enfermedad renal crónica estadio V. Tuvo varios ingresos por derrame pleural, en uno de ellos se apreció aspecto serohemático del líquido con estudio citológico negativo de células neoplásicas. Evolucionó tórpidamente y se sumaron al derrame la disfagia, la fiebre, la hemoptisis y una epigastralgia intensa. Los hallazgos anatomopatológicos mostraron un mesotelioma maligno tipo epitelioide con invasión al pulmón, al diafragma y al pericardio que lo llevó a fallecer con un tromboembolismo pulmonar en silla de montar. Las características morfológicas de este tumor son muy similares al adenocarcinoma, por lo que se requieren técnicas citoquímicas especiales para su diagnóstico(AU)
Subject(s)
Humans , Mesothelioma , Pulmonary EmbolismABSTRACT
Monitoring the biological activity in biotrickling filters is difficult since it implies estimating biomass concentration and its growth yield, which can hardly be measured in immobilized biomass systems. In this study, the characterization of a sulfide-oxidizing nitrate-reducing biomass obtained from an anoxic biotrickling filter was performed through the application of respirometric and titrimetric techniques. Previously, the biomass was maintained in a continuous stirred tank reactor under steady-state conditions resulting in a growth yield of 0.328 ± 0.045 g VSS/g S. To properly assess biological activity in respirometric tests, abiotic assays were conducted to characterize the stripping of CO2 and sulfide. The global mass transfer coefficient for both processes was estimated. Subsequently, different respirometric tests were performed: (1) to solve the stoichiometry related to the autotrophic denitrification of sulfide using either nitrate or nitrite as electron acceptors, (2) to evaluate the inhibition caused by nitrite and sulfide on sulfide oxidation, and (3) to propose, calibrate, and validate a kinetic model considering both electron acceptors in the overall anoxic biodesulfurization process. The kinetic model considered a Haldane-type equation to describe sulfide and nitrite inhibitions, a non-competitive inhibition to reflect the effect of sulfide on the elemental sulfur oxidation besides single-step denitrification since no nitrite was produced during the biological assays.
Subject(s)
Air Filters , Bioreactors/microbiology , Filtration/methods , Nitrates/metabolism , Sulfides/metabolism , Anaerobiosis , Oxidation-ReductionABSTRACT
Biogas biodesulfurization by an anoxic biotrickling filter packed with open pore polyurethane foam at the laboratory scale (packed volume 2.4L) has been studied. The biotrickling system was operated for 620 days with biogas supplied continuously and two nitrate feeding regimes were tested (manual and programmed). Biomass immobilization was carried out under the manual nitrate feeding regime and a study was then carried out on the effects on removal efficiency of the following parameters: nitrate source, H2S inlet load, nitrate concentration, sulfate accumulation, temperature, pH and trickling liquid velocity. The effect of increased H2S inlet load was studied under the programmed nitrate feeding regime. The results show that a removal efficiency of 99% can be obtained when working under the following conditions: inlet loads below 130gSm(-3)h(-1), a programmed nitrate feeding system, temperature of 30°C, sulfate concentration below 33gL(-1), a pH between 7.3 and 7.5, and a trickling liquid velocity higher than 4.6mh(-1).
Subject(s)
Biofuels , Hydrogen Sulfide/isolation & purification , Anaerobiosis , Biomass , Nitrates , PolyurethanesABSTRACT
El presente trabajo recopila los antecedentes de las bibliotecas, hasta llegar a las bibliotecas en línea. Se realiza una breve comparación entre los diferentes tipos de bibliotecas existentes. Se describe la biblioteca digital personalizable, la cual permite la socialización del conocimiento, ideal para ser utilizada en las universidades. Se refieren sus principales características y la posibilidad de ser utilizada como complemento de las bibliotecas físicas con las que cuentan las universidades.(AU)
This work compiles the history of libraries, reaching to libraries online. A brief comparison between different types of libraries. Describes the customizable digital library which allows socialization of knowledge, ideal for universities use. Regards its main features and the possibility of being used as a complement to physical libraries at their disposal universities.(AU)
Subject(s)
Libraries, Digital , Information Technology , UniversitiesABSTRACT
El presente trabajo recopila los antecedentes de las bibliotecas, hasta llegar a las bibliotecas en línea. Se realiza una breve comparación entre los diferentes tipos de bibliotecas existentes. Se describe la biblioteca digital personalizable, la cual permite la socialización del conocimiento, ideal para ser utilizada en las universidades. Se refieren sus principales características y la posibilidad de ser utilizada como complemento de las bibliotecas físicas con las que cuentan las universidades.
This work compiles the history of libraries, reaching to libraries online. A brief comparison between different types of libraries. Describes the customizable digital library which allows socialization of knowledge, ideal for universities use. Regards its main features and the possibility of being used as a complement to physical libraries at their disposal universities.
Subject(s)
Information Technology , UniversitiesABSTRACT
The present work aims to use a two-stage biotrickling filters for simultaneous treatment of hydrogen sulphide (H(2)S), methyl mercaptan (MM), dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). The first biofilter was inoculated with Acidithiobacillus thiooxidans (BAT) and the second one with Thiobacillus thioparus (BTT). For separate feeds of reduced sulphur compounds (RSC), the elimination capacity (EC) order was DMDS>DMS>MM. The EC values were 9.8 g(MM-S)/m(3)/h (BTT; 78% removal efficiency (RE); empty bed residence time (EBRT) 58 s), 36 g(DMDS-S)/m(3)/h (BTT; 94.4% RE; EBRT 76 s) and 57.5 g(H2S-S)/m(3)/h (BAT; 92% RE; EBRT 59 s). For the simultaneous removal of RSC in BTT, an increase in the H(2)S concentration from 23 to 293 ppmv (EBRT of 59 s) inhibited the RE of DMS (97-84% RE), DMDS (86-76% RE) and MM (83-67% RE). In the two-stage biofiltration, the RE did not decrease on increasing the H(2)S concentration from 75 to 432 ppmv.
Subject(s)
Acidithiobacillus thiooxidans/metabolism , Filtration/methods , Sulfur Compounds/isolation & purification , Thiobacillus/metabolism , Waste Disposal, Fluid/methods , Water Purification/methods , Chromatography, Gas , Filtration/instrumentation , Sulfur Compounds/metabolismABSTRACT
The decolouration of fermentation residues (vinasse) and liquid extract of coffee pulp by the mushroom Pleurotus ostreatus was studied in addition to laccase activity. The fungus was inhibited in both residues when they remained undiluted. In submerged cultivation on wastewaters a good production of biomass (14.8 g/l for vinasse and 5.4 g/l for extract of coffee pulp) and also laccase activity (14.1 U/ml for vinasse and 3.0 U/ml for extract of coffee pulp) up to the 10 days of fermentation was observed, being significantly greater in the culture with vinasse. It was shown that treatment with this mushroom reduces both the chemical oxygen demand and the colour, contributing to their biological treatment.
