Hidrólisis ácida de celulosa y biomasa lignocelulósica asistida con líquidos iónicos

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 23-04-201

Complete chemical hydrolysis of cellulose into fermentable sugars via ionic liquids and antisolvent pretreatments

This work describes a relatively simple methodology for efficiently deconstructing cellulose into monomeric glucose, which is more easily transformed into a variety of platform molecules for the production of chemicals and fuels. The approach undertaken here first involves the dissolution of cellulose in an ionic liquid (IL), followed by a second reconstruction step aided by an antisolvent. The regenerated cellulose exhibited strong structural and morphological changes, as revealed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. These changes dramatically affect the hydrolytic reactivity of the cellulose with dilute mineral acids. As a consequence, the glucose yield obtained from the deconstructed-reconstructed cellulose was substantially higher than that achieved via hydrolysis of the starting cellulose. Factors that affect the hydrolysis reaction include the type of cellulose substrate, the type of IL used in the pretreatment and the type of acid used in the hydrolysis step. The best results were obtained by treating the cellulose with IL and using phosphotungstic acid (0.067 mol/L) as a catalyst at 413 K. Under these conditions, the conversion of cellulose was almost complete (> 99 %), with a glucose yield of 87 % after only 5 h of reaction.Comunidad de Madrid (Spain) S2009/ENE-1743CSIC (Spain) 201180E038Peer reviewe

Fractionation of Lignocellulosic Biomass by Selective Precipitation from Ionic Liquid Dissolution

We propose the treatment of barley straw with 1-ethyl-3-methylimidazolium acetate [EMIMAcO] ionic liquids (ILs) and subsequent precipitation with antisolvent mixtures, thus allowing the separation of the sugar-rich fractions (cellulose and hemicellulose) from the lignin fraction. For this purpose, different concentration ranges of acetone:water antisolvent mixtures were studied. In all cases, a high recovery percentage and a high and effective separation of fractions was achieved for 1:1 acetone:water. The fractionated lignocellulosic compounds were studied by using infrared spectroscopy, scanning electron microscopy and 1H nuclear magnetic resonance characterization techniques. This method allows the possibility of reusing IL, confirming the versatility of the established method. The fraction rich in cellulose and hemicellulose was subjected to acid hydrolysis (0.2 mol/L H2SO4) for 5 h at 140 °C, obtaining a yield of total reducing sugars of approximately 80%, much higher than those obtained in non-pretreated samples.This research was funded by Comunidad de Madrid (Spain) and ERDF (European Regional Development Fund), grant numbers S2013/MAE-2882 (RESTOENE-2-CM), S2018/EMT-4344 (BIOTRES-CM) and CSIC (201880E029). M.L.-S. acknowledges the support of the European Social Fund and Community of Madrid for her contracPeer reviewe

Solvent Additive-Induced Deactivation of the Cu-ZnO(Al₂O₃)-Catalyzed γ-Butyrolactone Hydrogenolysis:A Rare Deactivation Process

[Image: see text] This work reports initial results on the effect of low concentrations (ppm level) of a stabilizing agent (2,6-di-tert-butyl-4-methylphenol, BHT) present in an off-the-shelf solvent on the catalyst performance for the hydrogenolysis of γ-butyrolactone over Cu–ZnO-based catalysts. Tetrahydrofuran (THF) was employed as an alternative solvent in the hydrogenolysis of γ-butyrolactone. It was found that the Cu–ZnO catalyst performance using a reference solvent (1,4-dioxane) was good, meaning that the equilibrium conversion was achieved in 240 min, while a zero conversion was found when employing tetrahydrofuran. The deactivation was studied in more detail, arriving at the preliminary conclusion that one phenomenon seems to play a role: the poisoning effect of a solvent additive present at the ppm level (BHT) that appears to inhibit the reaction completely over a Cu–ZnO catalyst. The BHT effect was also visible over a commercial Cu–ZnO–MgO–Al(2)O(3) catalyst but less severe than that over the Cu–ZnO catalyst. Hence, the commercial catalyst is more tolerant to the solvent additive, probably due to the higher surface area. The study illustrates the importance of solvent choice and purification for applications such as three-phase-catalyzed reactions to achieve optimal performance

Correction to “Solvent Additive-Induced Deactivation of the Cu–ZnO(Al2O3)-Catalyzed γ-Butyrolactone Hydrogenolysis: A Rare Deactivation Process”

The authors regret that Figure 8 contained a typographic error in the original publication. The x-axis labels should have been labeled as Time (min) instead of Conversion (%). The discussion in the text is correct and remains valid. However, the wrong labeling of the axes can lead to confusion. Below, an amended Figure 8 can be found. The authors would like to apologize for any inconvenience caused. (Figure Presented).</p

H2 oxidation versus organic substrate oxidation in non-heme iron mediated reactions with H2O2

Herein we show that species generated upon reaction of α-[Fe(CF3SO3)2(BPMCN)] (BPMCN = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane) with H2O2 (putatively [FeV(O)(OH)(BPMCN)]) is able to efficiently oxidize H2 to H2O even in the presence of organic substrates, while species formed in the presence of acetic acid (putatively [FeV(O)(OAc)(BPMCN)]) prefer organic substrate oxidation over H2 activation. Mechanistic implications have been analysed with the aid of computational methodsThis work was supported by Spanish Ministerio de Economia y Competitividad (CTQ2012-37420-C02-02 and 01) European Research Council (StG 239910), and Generalitat de Catalunya (2014 SGR 862 and ICREA Academia award to MC). J.Ll.-F. thanks the CELLEX foundation for the starting career program for financial suppor

Riqueza de moluscos acuáticos en las Cuencas Hidrológicas Río Grijalva-Villahermosa y Río Tonalá, Lagunas del Carmen-Machona en Tabasco, México

The richness of aquatic snails was determined, on two basin of the state of Tabasco, samples were taken at 23 locations during two seasons, the rainy season (September and October 2008) and the dry season (April and May 2009). The organisms were collected from the roots of Rhizophora mangle (red mangrove) and those adhered to Eichhornia crassipes (water hyacinth). Thirteen gastropods and three bivalves associated with water hyacinth as well as four gastropods and four bivalves from mangrove roots were collected. The CH Grijalva River-Villahermosa present he highest species richness 21 and 20 species were within the Subc. Carrizal River 52.17% of the species were from freshwater and collected on water lily; 30.44% were collected were brackish and collected on mangrove roots; 17.39% on euryhaline and harvested on both vegetation types. As for the estimation of richness, a difference of one to five species was observed between then species richness estimated and that estimated with SChao2. Of the 23 species recorded in this study none are listed in the NOM-059-SEMARNAT-2010. The most abundant freshwater species on the two basins were Pyrgophorus coronatus, Mexinauta impluviata, Littoridinops tenuipes, Mayabina polita and Pomacea flagellata; and brackish Mytilopsis leucophaeata, Brachidontes exustus, Littorina angulifera, Neritina virginea and Musculium transversum. The greatest richness and abundance of molluscs associated with both E. crassipes as R. mangle were present during the rainy season.En dos Cuencas del estado de Tabasco, se determinó la riqueza de moluscos acuáticos, los muestreos se realizaron en 23 localidades durante dos temporadas, lluvias (septiembre y octubre 2008) y estiaje (abril y mayo 2009). Los organismos fueron recolectados sobre las raíces de Rhizophora mangle (mangle rojo) y adheridas a Eichhornia crassipes (lirio acuático). Se recolectaron, un total de 23 especies 13 gasterópodos y tres bivalvos asociados a lirio acuático y cinco gasterópodos y cuatro bivalvos en raíces de mangle. La mayor riqueza específica se presentó en la Cuenca HidrológicaRío Grijalva-Villahermosa con 21 especies y dentro de ella la Subcuenca Río Carrizal con 20 especies. El 52.17%, de las especies recolectadas fueron dulceacuícolas y recolectadas sobre lirio acuático; el 30.44% salobres y recolectadas en raíces de mangle; el 17.39% eurihalinas y recolectadas en ambos tipos de vegetación. En cuanto a la estimación de la riqueza, se observó una diferencia de una a cinco especies entre la riqueza específica observada y la estimada por SChao2. De las 23 especies registradas ninguna se encuentra listada en la NOM-059-SEMARNAT-2010. Las especies dulceacuícolas más abundantes en las dos cuencas fueron Pyrgophorus coronatus, Mexinauta impluviata, Littoridinops tenuipes, Mayabina polita y Pomacea flagellata; y las salobres Mytilopsis leucophaeata, Brachidontes exustus, Littorina angulifera,Neritina virginea y Musculium transversum. La mayor riqueza y abundancia de moluscos asociados tanto a E. crassipes como a R. mangle se presentaron durante la temporada de lluvias

Veränderungen im Leukozytenprofil der Dupontlerche ( Chersophilus duponti ) in Spanien und Marokko

[EN] Stress in birds has been widely studied through the measurement of heterophil-to-lymphocyte ratio (H/L ratio). In this study we aimed to assess for the first time the potential variation of stress, measured as H/L ratio, associated to geography (between-country variation) and seasonality (between seasons and within the breeding season), as well as the leukocyte profiles, in the threatened Dupont’s Lark (Chersophilus duponti), using samples from Spain and Morocco. Furthermore, we tested whether variation in H/L ratio was associated with variables such as population density, presence of blood parasites and individual body condition. We found that H/L ratio did not vary between countries, but individuals captured during the breeding season showed higher values of H/L compared to non-breeding ones. Neither male density, nor date within the breeding season had an effect on the H/L ratio. In Spain, individuals with higher body condition showed lower H/L ratio regardless of whether they were malaria-infected. In Morocco, malaria-infected individuals showed higher values of H/L ratio than the non-infected birds. Moreover, we found that our average values of H/L ratio in Morocco were within the ranges of other passerines, but not in Spain. Individuals with higher H/L ratios may be more stressed or present higher capability to face stressful situations. Although H/L ratio is a useful and relatively easy way to obtain measure of stress, the impact that the environment might have on stress and the way it is explained by H/L ratio must be addressed carefully. This study provides new insight for this species’ biology and provides useful reference information to test the status and survival of other populations.[DE] Stress bei Vögeln ist durch die Messung des Verhältnisses von Heterophilen zu T-Lymphozyten (H/L-Verhältnis) umfassend untersucht worden. In dieser Studie wollten wir zum ersten Mal die potentiellen Veränderungen des Stresses in Verbindung mit der Geografie (Unterschiede zwischen einzelnen Ländern) und der Saisonalität (zwischen den Jahreszeiten und innerhalb der Brutsaison), gemessen als H/L-Verhältnis, sowie die Leukozytenprofile bei der bedrohten Dupontlerche (Chersophilus duponti) anhand von Proben aus Spanien und Marokko bewerten. Darüber hinaus haben wir untersucht, ob das H/L-Verhältnis mit Variablen wie der Populationsdichte, dem Vorhandensein von Blutparasiten und der individuellen physischen Verfassung zusammenhängt. Wir stellten fest, dass das H/L-Verhältnis zwischen den einzelnen Ländern nicht variierte, aber die während der Brutzeit gefangenen Tiere höhere H/L-Werte aufwiesen als nicht brütende Tiere. Weder die Dichte an Männchen, noch der Zeitpunkt innerhalb der Brutsaison hatten einen Einfluss auf das H/L-Verhältnis. In Spanien wiesen Tiere mit einer besseren physischen Verfassung ein niedrigeres H/L-Verhältnis auf, unabhängig davon, ob sie mit Malaria infiziert waren. In Marokko zeigten malariainfizierte Vögel höhere Werte des H/L-Verhältnisses als nicht infizierte. Außerdem stellten wir fest, dass unsere Durchschnittswerte für das H/L-Verhältnis in Marokko innerhalb der Werte für andere Sperlingsvögel lagen, nicht aber in Spanien. Tiere mit einem höheren H/L-Verhältnis sind möglicherweise gestresster oder besser in der Lage, mit Stresssituationen umzugehen. Obwohl das H/L-Verhältnis ein nützliches und relativ einfach zu beschaffendes Maß für Stress ist, muss der eventuelle Einfluss der Umwelt auf Stress und die Möglichkeiten, diesen durch das H/L-Verhältnis zu erklären, sorgfältig untersucht werden. Diese Untersuchung bietet neue Einblicke in die Biologie dieser Art und liefert nützliche Referenzinformationen für die Bestimmung des aktuellen Status und für das Überleben anderer Populationen.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.This study was partially funded by the authors, the Spanish Ministry of Environment (MMA; J.J. Areces and B. Heredia), the Spanish Agency for International Cooperation (AECI), and the LIFE Ricoti (LIFE15-NAT-ES-000802), supported by the European Comisison. D.B.R. was supported by FPI-UAM fellowship from the Universidad Autónoma de Madrid (UAM), and the collaboration of the Instituto de Investigación en Recursos Cinegéticos (IREC-CSIC-UCLM). We wish to thank the Servicio de Vida Silvestre of Conselleria D’infraestructures, Territori i Medi Ambient (Generalitat Valenciana) and the Moroccan government for ringing permits and supporting our work. We thank V. Garza, A. Ramírez, R. del pozo, E. Juarez, E.L. García de la Morena, F. Suárez, M. Radi, M. Znari and M. Alouí, and the Colectivo Ornitológico Cigüeña Negra for their help during fieldtrips and arrangements. We also thank two anonymous referees whose helpful comments contributed to improve the paper. This work was approved by the Local Ethical Committee for Animal Experiments of the Autónoma University of Madrid (CEI80-1468-A229).Peer reviewe

Consenso de inmunizaciones en adultos con enfermedades reumáticas inflamatorias crónicas autoinmunes

Aumento del riesgo de infecciones prevenibles y sus complicaciones en pacientes con enfermedades reumáticas inflamatorias crónicas (ERICA), con y sin tratamiento con inmunosupresores (IS), y beneficios de la vacunación

Lo glocal y el turismo. Nuevos paradigmas de interpretación.

El estudio del turismo se realiza desde múltiples escalas y enfoques, este libro aborda muchos temas que es necesario discutir desde diversas perspectivas; es el caso de la reflexión sobre la propia disciplina y sus conceptos, así como los asuntos específicos referidos al impacto territorial, los tipos de turismo, las cuestiones ambientales, el tema de la pobreza, la competitividad, las políticas públicas, el papel de las universidades, las áreas naturales protegidas, la sustentabilidad, la cultura, el desarrollo, la seguridad, todos temas centrales documentados y expuestos con originalidad y dominio del asunto. Lo multiescalar es básico para la comprensión del sistema turístico, sistema formado de procesos globales, regionales y locales. El eje de discusión del libro es lo glocal, esa interacción entre lo nacional y local con lo global