Repositorio Digital Ikiam (Univ. Regional Amazónica)
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Exploring a Low-Cost Valorization Route for Amazonian Cocoa Pod Husks through Thermochemical and Catalytic Upgrading of Pyrolysis Vapors
Get PDFEcuador as an international leader in the production of cocoa beans produced more than 300 000 tons in 2021; hence, the management and valorization of the 2 MM tons of waste generated annually by this industry have a strategic and socioeconomic value. Consequently, appropriate technologies to avoid environmental problems and promote sustainable development and the bioeconomy, especially considering that this is a megadiverse country, are of the utmost relevance. For this reason, we explored a low-cost pyrolysis route for valorizing cocoa pod husks from Ecuador’s Amazonian region, aiming at producing pyrolysis liquids (bio-oil), biochar, and gas as an alternative chemical source from cocoa residues in the absence of hydrogen. Downstream catalytic processing of hot pyrolysis vapors using Mo- and/or Ni-based catalysts and standalone γ-Al2O3 was applied for obtaining upgraded bio-oils in a laboratory-scale fixed bed reactor, at 500 °C in a N2 atmosphere. As a result, bimetallic catalysts increased the bio-oil aqueous phase yield by 6.6%, at the expense of the organic phase due to cracking reactions according to nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC–MS) results. Overall product yield remained constant, in comparison to pyrolysis without any downstream catalytic treatment (bio-oil ∼39.0–40.0 wt % and permanent gases 24.6–26.6 wt %). Ex situ reduced and passivated MoNi/γ-Al2O3 led to the lowest organic phase and highest aqueous phase yields. The product distribution between the two liquid phases was also modified by the catalytic upgrading experiments carried out, according to heteronuclear single-quantum correlation (HSQC), total correlation spectroscopy (TOCSY), and NMR analyses. The detailed composition distribution reported here shows the chemical production potential of this residue and serves as a starting point for subsequent valorizing technologies and/or processes in the food and nonfood industry beneficiating society, environment, economy, and research
Antimony pollution threatens soils and riverine habitats across China: An analysis of antimony concentrations, changes, and risks
Get PDFThe adverse effects of antimony (Sb) pollution on ecosystems and human health caused by its use, enrichment, and bioaccumulation have become global environmental problems, particularly in China. Based on a scientometric analysis of the research topics and evolution of Sb pollution, 210 peer-reviewed articles across 264 locations in China were selected to analyze Sb concentrations, changes, and risks in different environments (i.e., soil, sediment, and water). Substantially elevated concentrations were reported in the chosen environments throughout the studied literature, with approximately 36.6%, 41.3% and 20.8% of the soil, water and sediment sampling sites, respectively, exceeding the national and international guidelines. Although Sb concentrations were stable in water and sediment, those in soil slightly increased slightly over the past two decades. The majority of studies and the highest Sb concentrations were typically concentrated in Hunan, Guangxi, and Guizhou, where most Sb deposits and intensive mining and smelting activities are concentrated. A temporal analysis over three crucial periods of the Sb industry further indicated that Sb concentrations and pollution had increased in several provinces in recent years. The estimated risk quotient, using Monte Carlo simulations, indicated that species were markedly affected by Sb contamination, with 21.6% of events occurring in the high-risk category. The ingestion of contaminated soils posed the highest potential health risk to the population, with 47.9% of the events indicated to represent at least a low risk. Risks of water ingestion were estimated to exist in 4.9% of the simulated exposure events. More environmental campaigns for Sb pollution control are urgently needed, especially in Sb hotspots, to reduce environmental pressure and avoid direct and indirect hazards to organisms and populations
Use of GIS and R to estimate climate change impacts on groundwater recharge in Portoviejo River watershed, Ecuador
Get PDFFuture groundwater recharge estimations are helpful tools for water resources management. However, there is a need for more information about it in many parts of the world, including the Portoviejo River watershed (PRW) in the West of Ecuador, a semi-arid zone with a water deficit where climate change impacts could increase pressure on groundwater resources. Geographical Information Systems were used in this paper, owing to their simplicity of inputs and accuracy of outputs, to estimate current and future (2021–2070) groundwater recharge in the PRW. The study is divided into two stages: 1) a runoff map based on soil permeability, land use, and terrain slope, and 2) current and future recharge calculations using the Thornthwaite and Mather water balance method. Future precipitation and temperature data from an ensemble of four Global Circulation Models were used as inputs, along with a map of runoff spatial distribution. The representative concentration pathways (RCP) 4.5 and 8.5 were the climate change scenarios used in this study. The results showed that the location of the groundwater recharge zone would be impacted by future precipitation and temperature variability in both scenarios for the next fifty years. For the decade 2060–2070 and the scenario RCP 4.5, the highest recharge rate zones were located in the lowlands of the PRW surrounding Portoviejo city. In scenario RCP 8.5, the highest groundwater recharge areas increase considerably in the entire PRW. Currently, the highest groundwater recharge zones are in the highlands of the PRW. The future groundwater recharge scenarios provide information to decision-makers regarding land use, since the future groundwater recharge zones will be in the expansion areas of Portoviejo city
Entomotoxicology in Peckia intermutans (Diptera: Sarcophagidae) and its potential as a market for methanol determination in biological samples
Get PDFLa entomotoxicología forense emplea métodos analíticos e instrumentación en insectos necrófagos que se alimentan del tejido en descomposición para detectar drogas y otros xenobióticos. Empleándose principalmente en determinar la causa de muerte y estimar el intervalo post-mortem. Aunque los estudios entomotoxicológicos se centran en la detección de drogas, poca información se refiere al efecto del alcohol en las moscas de la carne. El metanol, a pesar de encontrarse en niveles bajo en las bebidas alcohólicas
disponibles comercialmente, su uso en bebidas adulteradas lo convierten en un potente veneno. Demostramos el potencial de Peckia intermutans (Diptera: Sarcophagidae) como marcador para la determinación de metanol utilizando cromatografía de gasesespectrometría de masas. Además, se estudiaron los efectos del metanol sobre el tiempo de desarrollo, la supervivencia y la morfología de las moscas de la carne. Las larvas se criaron en sustratos de hígado enriquecidos con metanol (300, 500 y 100 mg/kg) según las concentraciones encontradas en tejidos humanos implicados en la intoxicación por metanol. Los resultados demostraron que (i) HS-GC-MS detecta metanol en todos los estadios de Peckia intermutans; (ii) el metanol modifica el tiempo de desarrollo de las moscas de la carne; (iii) la supervivencia fue mayor a medida que aumentaba la concentración de metanol exógeno; y (iv) los cambios morfológicos fueron más evidentes en el peso. Esta investigación proporciona una valiosa adición al conocimiento actual de entomotoxicología de Ecuador. Peckia intermutans mostró potencial como marcador toxicológico de metanol en muestras biológicas. A pesar de esto, los cambios en la morfología y el ciclo de vida de las moscas de la carne deben investigarse y considerarse más a fondo al obtener resultados forenses. Estas variaciones pueden causar estimaciones erróneas del intervalo post-mortem.Tutor: Jonathan LIria Salazar ; Cotutora: Noroska Gabriela Salazar Mogolló
Expresión génica de HSP40 y HSP90 en respuesta al estrés térmico en Heliconius Erato Lativitta (Lepidóptera: Numphalidae)
Get PDFEl incremento de la frecuencia e intensidad de eventos extremos de temperatura representa un reto para la adaptación de las especies. Los organismos ectotermos, como los insectos, dependen de fuentes externas para la regulación de su temperatura corporal. Dentro del orden Lepidóptera, Heliconius erato lativitta es una mariposa que habita los bosques del Neotrópico y ha sido estudiada por varios siglos, llegándose a
evidenciar que el estrés térmico tiene una repercusión en su ciclo de vida. La inducción en la producción de proteínas de choque térmico (Hsp) mitiga la desnaturalización de proteínas y mantiene la homeostasis celular, sin embargo, los mecanismos epigenéticos en esta especie siguen sin resolverse. En este estudio se cuantificó la expresión génica de Heat shock protein 40 kDa (Hsp40) y Heat shock protein 90kDa (Hsp90) de H. e. lativitta usando RT-qPCR y el método de doble delta de Livak (ΔΔCt), en condiciones de estrés térmico, en tejidos de cabeza, tórax y abdomen, de individuos machos y hembras. En base a un alineamiento local se identificaron 2 genes de la familia Hsp40, los homólogos DnaJ-1 y DnaJ-5, y 1 gen de la familia Hsp90. Se mostró que DnaJ-1 y DnaJ- 5 se infraexpresan a 40 °C y se sobreexpresan en condiciones de shock a 5 °C, por otro lado, Hsp90, presentó sobreexpresión a 40 °C. Los tejidos del abdomen y de la cabeza
mostraron la mayor sobreexpresión de todas las tagmas, mientras que, el tórax, presentó infraexpresión en todos los tratamientos. El uso de modelos lineales generalizados mostró que la variabilidad génica fue causada en mayor medida por los tratamientos de temperatura, seguidos por los diferentes tejidos, no se encontraron diferencias significativas entre sexos. Este estudio provee información para comprender
uno de los mecanismos epigenéticos de adaptación que tienen las mariposas tropicales ante el cambio climático.Tutora: Caroilne Nicole Bacquet Pére
Viabilidad del suo de microesferas de oxiyoduro de bismuto (BIOI) para la remediación de agua: un análisis citotóxico
Get PDFEn este estudio, se evaluó la toxicidad de dos tipos de oxihaluros de bismuto (BiOX): microesferas de BiOI y nanocinturones de Bi12O17Cl2 en tres líneas celulares diferentes: fibroblastos de piel humana (HFF), macrófagos de ratón (RAW 264.7) y células renales de mono de Macaca mulatta (LlcMk2). Se investigaron varios parámetros, como la exposición a la luz, diferentes concentraciones, tiempo de exposición y el tipo de BiOX (X= I, Cl). Se utilizó la viabilidad celular relativa medida como la intensidad de fluorescencia (IF) mediante la conversión de resazurina a resofurina. Los resultados revelaron que la citotoxicidad de los BiOX dependía de la línea celular estudiada. Se observaron efectos en la proliferación celular y cambios morfológicos en las células expuestas a una concentración de 1,000 µg/mL de BiOX. Sin embargo, no se
encontraron efectos dependientes de la concentración en todas las líneas celulares. Solo se encontraron diferencias significativas entre la viabilidad celular y la concentración en las células de macrófagos. Además, se observó una buena compatibilidad de los BiOX incluso a altas concentraciones con los eritrocitos humanos.
Estos hallazgos proporcionan información inicial sobre la toxicidad de los BiOX en diferentes líneas celulares y respaldan la necesidad de realizar más investigaciones para comprender mejor los efectos toxicológicos y la seguridad de estos nanomateriales en aplicaciones futuras. En resumen, este trabajo contribuye al conocimiento actual sobre la toxicidad de las BiOI y Bi12O17Cl2 en células in vitro, destacando la importancia
de investigaciones adicionales en este campo.Tutor: Miguel Herrera Robledo ; Cotutores Mgs. Marco Viteri y Fabián Aguila
Development of iron-doped bacterial cellulose from Ilex Guayusa and its application in the removal of Cadmium from aqueous solutions
Get PDFLa presencia de metales pesados en las masas de agua es un problema medioambiental y sanitario mundial, que afecta especialmente a la vulnerable región amazónica. En Ecuador, el 35% de los recursos hídricos contienen niveles peligrosos de contaminantes, lo que supone una amenaza inminente para las comunidades locales. En este estudio, se obtuvieron películas de celulosa bacteriana utilizando un sustrato basado en una planta ancestral llamada guayusa (Ilex guayusa) como alternativa eficiente y prometedora para su producción en la región. Se desarrollaron membranas con diferentes porcentajes de hierro (Fe) para la remoción de iones cadmio (Cd2+) de soluciones acuosas. Los resultados de la caracterización revelaron que los 4 tipos de
muestras de celulosa bacteriana exhibieron espectros FTIR consistentes, con ligeras variaciones en la región de la huella dactilar y en la región de 700-450 cm-1 correspondientes a la presencia de grupos Fe-O. Además, las imágenes SEM-EDS confirmaron la presencia uniforme de partículas de hierro en la estructura de la celulosa bacteriana, con diámetros que oscilaban entre 2 µm y 2,5 µm en la superficie. Los resultados del espectrómetro de absorción atómica indican que las membranas con distintos porcentajes de hierro (1%, 3% y 5%) presentan mejores propiedades de adsorción que el control. En particular, la celulosa con un 3% de hierro demostró el mejor rendimiento en todas las dosis de Cd2+ evaluadas (1 ppm, 1,5 ppm, 2,5 ppm, 3,5 ppm,
5 ppm y 7,5 ppm), alcanzando porcentajes de eliminación de hasta el 70% de los iones con una capacidad de adsorción de 2,6175 mg/g en las concentraciones más altas. Las membranas de celulosa con un 3% de hierro podrían utilizarse como materiales de adsorción para la eliminación eficaz de iones de cadmio en medios acuosos contaminados con metales. Este estudio ofrece una alternativa innovadora, sostenible y
eficiente para la remediación de aguas contaminadas en una región donde la minería, la extracción y otras actividades humanas han tenido un impacto ambiental significativo.Tutora: Yanet Villasana ; Cotutor Carlos Nava
Optimization of microfibrillated cellulose isolation from cocoa pod husk via mild oxalic acid hydrolysis: A response surface methodology approach
Get PDFTheobroma cacao L. species, cultivated worldwide for its valuable beans, generates up to 72% weight of the fruit as waste. The lack of reutilization technologies in the cocoa agroindustry has hindered the exploitation of valuable bio-components applicable to the generation of high value added bioproducts. One such bioproduct is microfibrillated cellulose (MFC), a biopolymer that stands out for its desirable mechanical properties and biocompatibility in biomedical, packing, 3D printing, and construction applications. In this study, we isolated microfibrillated cellulose (MFC) from cocoa pod husk (CPH) via oxalic acid hydrolysis combined with a steam explosion. MFC isolation started with the Solid/Liquid extraction via Soxhlet, followed by mild citric acid hydrolysis, diluted alkaline hydrolysis, and bleaching pre-treatments. A Response Surface Methodology (RSM) was used to optimize the hydrolysis reaction at levels between 110 and 125 °C, 30–90 min at 5–10% (w/v) oxalic acid concentration. The cellulose-rich fraction was characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) analyses. Characterization analyses revealed a cellulose-rich polymer with fibers ranging from 6 to 10 μm, a maximum thermal degradation temperature of 350 °C, and a crystallinity index of 63.4% (peak height method) and 29.0% (amorphous subtraction method). The optimized hydrolysis conditions were 125 °C, 30 min, at 5% w/v oxalic acid: with a 75.7% yield. These results compare with MFC obtained through highly concentrated inorganic acid hydrolysis from different biomass sources. Thus, we show a reliable and greener alternative chemical treatment for the obtention of MFC
Péptidos de veneno animal y venenos
No full textVenoms are not uncommon biochemical weapons that only a
few species possess. It is estimated that 220,000 animal spe cies produce venom, corresponding to approximately 15%
of all animal species. Animal venom and poisons can be
found in almost all habitats that spiders, scorpions, snakes,
amphibians, hymenopteran insects, marine invertebrates,
anemones, or jellyfishes inhabit. Animal venom and poisons
are species-specific biococktails of dozens or even hundreds
of bioactive molecules (Oliveira et al. 2022), which have
arisen through positive evolutionary processes that enable
animals to improve predation efficiency, to defend and deter
competitor
Diversity and composition of ferns and lycophytes in a fragmented landscape in Ecuadorian Amazonia
No full textTropical forests have been subjected to increasing deforestation, leading to severe habitat loss and
fragmentation of the landscape. Studies of various plant groups-indicate alteration in species diversity and
assemblage composition in response to these impacts. How theses impacts affect ferns and lycophytes,
however, is less well known. In this study we evaluate the effects of habitat loss and fragmentation on
ferns and lycophytes in lowland non-inundated forests in Ecuadorian Amazonia. We obtained assemblage
information from thirteen plots located in gradients of habitat loss and fragmentation (as measured by
the landscape fragmentation index: fragindex) and used community and diversity indices to evaluate
species responses. We found 3,824 individuals of 55 species. The plot with the highest fragindex value
(more than 20% of habitat loss and fragmentation) had the lowest diversity, but the highest diversity
was found in plots with fragindex values from 12% to 21% of habitat loss and fragmentation rather than
in the landscapes without deforestation. Although community composition varied along the fragindex
gradient, species turnover was not significantly related to this index. These results suggest that changes
in the landscape caused by deforestation alter the availability of habitats, consequently affecting the
distribution patterns of ferns and lycophytes