Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14823

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Acerola (Malpighia spp.) Waste: A Sustainable Approach to Nutraceutical, Pharmaceutical, and Energy Applications
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2023) Jose-Roberto, Vega-Baudrit; Camacho Elizondo, Melissa; Batista-Menezes, Diego; Corrales-Ureña, Yendry; Zúñiga, Juan Miguel; Mora Chacón, Arturo; Lecot, Nicole; Castillo Henríquez, Luis; Lopretti, Mary
Abstract. This study reviews the many uses for waste generated from acerola (Malpighia spp.) production, a tropical fruit renowned for its nutrient-rich content. Traditionally considered an environmental burden, this waste is now gaining attention for its sustainable applications in green technology. This review outlines the extraction of valuable bioactive compounds, like polyphenols, carotenoids, and pectin, that can be extracted from the acerola fruit and acerola waste, and it also delves into its potential in materials science, particularly in the creation of pharmaceutical formulations, nanomaterials, composites, biofuels, and energy applications. On the medical front, the paper highlights the promise that acerola waste holds in anti-inflammatory, antihyperglycemic, and anticancer therapies. By outlining challenges and opportunities, the review emphasizes the untapped potential of acerola waste as a resource for high-value products. These findings suggest a paradigm shift, turning what has been considered waste into a sustainable asset, thereby encouraging environmentally responsible practices within the fruit industry.
Adaptación del Método de Descarga de Arco Voltaico para la Síntesis de Nanotubos de Carbono de Pared Simple
(Universidad del País Vasco (España), 2011) Ramirez Amador, Sergio Alberto; Jose-Roberto, Vega-Baudrit
Resumen. Se obtuvieron nanotubos de carbono de pared simple (SWCNT, en inglés) por el método de descarga de arco voltaico. El anterior es un método sencillo, económico y energéticamente eficiente empleado para la síntesis de nanotubos de carbono de alta calidad sin la necesidad de catalizadores. En esta investigación, la metodología fue optimizada variando el amperaje de la fuente de poder, naturaleza y presión del gas de protección. La caracterización de los nanotubos de carbono de pared simple obtenidos fue realizada por análisis microscópicos (SEM, TEM y AFM), térmicos (TGA) y espectroscópicos (FTIR).
Aislamiento y purificación de la enzima lacasa: evaluación de su potencial biodegradador en residuos agrícolas
(Sociedad Mexicana de Biotecnología y Bioingeniería (México), 2020) Valdés, Sandra; Garita, Cristian; Esquivel, Carmenza; Villegas Peñaranda, Luis Roberto
Resumen. A nivel mundial, el inadecuado manejo de los residuos está generando el deterioro acelerado del planeta y, Costa Rica no es la excepción. Con el objetivo de aislar y purificar la enzima lacasa para la evaluación de su potencial degradador de residuos agrícolas, se obtuvieron cultivos axénicos de Ganoderma applanatum y Trichoderma harzianum, en los cuales se determinó la actividad de la enzima lacasa mediante la oxidación del ABTS. El aislamiento de G. applanatum registró la mayor concentración de la enzima, por lo que fue parcialmente purificada mediante electroforesis en gel de poliacrilamida (SDS-PAGE), luego el extracto enzimático fue purificado con filtro Vivaspin de 20 ml y peso molecular 50 kDa. Posteriormente, se llevaron a cabo los tratamientos enzimáticos de los residuos agroindustriales de caña, piña y banano durante 45 días. Los resultados mostraron que la enzima redujo la concentración de lignina en los residuos de banano y caña en lapsos que oscilaron entre 15 y 45 días.
An in situ approach to entrap ultra-small iron oxide nanoparticles inside hydrophilic electrospun nanofibers with high arsenic adsorption
(Elsevier (Países Bajos), 2023) Torasso, Nicolás; Vergara-Rubio, Alicia; Pereira, Reinaldo; Martinez-Sabando, Javier; Jose-Roberto, Vega-Baudrit; Cerveny, Silvina; Goyanes, Silvia
Abstract. The problem of arsenic contamination in water demands sustainable, scalable, and easy-to-implement solutions. Various nano-adsorbents flourished in the last decade, but their use alone requires additional filtering processes to avoid environmental contamination. This work presents a simple, efficient, green approach to overcome this inconvenience while maximizing adsorption capacity. We show for the first time a novel approach to synthesizing ultra-small nanoparticles (IONPs) within electrospun hydrophilic poly(vinyl alcohol) (PVA) nanofibers, avoiding NPs release into the environment when submerged in water. The in-situ synthesis favor enhanced arsenic adsorption capacity due to the excellent dispersion, tiny size, and surface availability of IONPs, reaching 3.5 mg/g at 10 μg/L. We show that IONPs alter the polymeric matrix properties, such as the glass transition temperature and crystallinity, by preventing the formation of strong hydrogen bond inter/intramolecular interactions of PVA. Insolubility and swelling capacity are essential characteristics of this membrane, which allow solution interchange for arsenic adsorption onto IONPs. Isotherm studies show that the increase from 1 wt% to 3 wt% of IONPs content decreases the active sites for adsorption per mass of IONPs. Still, it does not alter the reusability of the membrane, which reaches at least 3 adsorption cycles with 80 % efficiency. We discuss the adsorption mechanisms and show that phosphate anions partially inhibit As(V) adsorption and that the membranes are also highly capable of removing Cr(VI), independently of the presence of Ni(II).
Aplicación de un método para evaluar el impacto ambiental de proyectos de construcción de edificaciones universitarias
(2016) mora barrantes, jose carlos; Molina-León, Oscar Mario; Sibaja, José
La evaluación de impacto ambiental consiste en la identificación y valoración de los impactos potenciales de proyectos respecto a los componentes físicos, químicos y biológicos, culturales, económicos y sociales, con el fin de que mediante la planificación y la correcta toma de decisiones se desarrollen aquellas actuaciones más compatibles con el medio ambiente. El objetivo principal es asegurar que las consideraciones ambientales sean explícitamente expresadas e incluidas en el proceso de toma de decisiones y anticipar y evitar, minimizar y compensar los efectos negativos sobre el medio ambiente. Al proceso de evaluación ambiental de un proyecto se le pueden aplicar diferentes técnicas metodológicas, algunas generales, otras de carácter más específico. En Costa Rica la metodología más común es la elaborada por la Secretaría Técnica Ambiental (SETENA, 2016A). Con el fin de valorar el impacto ambiental de los proyectos de construcción en una universidad, se aplicó el formulario ambiental del SETENA, identificándose la magnitud de los factores, componentes y subcomponentes ambientales significativos de cada uno de ellos (SETENA, 2016B). La investigación permitió obtener y analizar los valores de significancia del impacto ambiental de los proyectos en función de: la cantidad de aspectos ambientales, la aplicación de reglamentos específicos, la ubicación geográfica del proyecto y el uso guías ambientales. Se identificaron los proyectos con mayor o menor cantidad de subcomponentes ambientales significativos, metros cuadrados de construcción, y valores de impacto ambiental preeliminar, ponderado y final. Se analizó la relación existente entre la cantidad de aspectos ambientales significativos de cada proyecto y su influencia en el valor final de significancia ambiental.
Application of a Sulfur Removal Hydrometallurgical Process in a Lead-Acid Battery Recycling Plant in Costa Rica
(Scientific Research Publishing Inc., 2017) Navarro-Monge, Marta; Esquivel-Hernández, Germain; Sibaja, José; mora barrantes, jose carlos; Sanchez-Murillo, Ricardo; Valdés-González, Juan; Bolaños-Ulloa, Pablo
This study presents the implementation of a desulphurization process for lead recycling under different chemical and physical conditions using pyro-metallurgical processes. Desulphurization was done using a hydrometallurgical process using sodium carbonate as a desulphurization agent and different lead bearing loads compositions. Waste characterization included: SO2 concentrations in the stack emissions, total lead content in the furnace ash, the total lead content in the slag, and the toxicity characteristic leaching procedure (TCLP). A significant reduction in SO2 emissions was achieved (~55% reduc tion) where mean SO2 concentrations changed from 2193 ± 135 ppm to 1006 ± 62 ppm after the implementation of the modified processes. The desulfurized lead paste (i.e. the metallic fraction lead of the battery) of the modified process exhibited an improvement in the concentration of the lead in the TCLP test, with an average value of 1.5 ppm which is below US EPA limit of 5 ppm. The traditional process TCLP mean value for the TCLP was 54.2 ppm. The total lead content in the bag house ashes shows not significant variations, when comparing the desulphurization (67.6% m/m) and non-desulphurizationvprocess (64.9% m/m). The total lead mean content in the slag was higher in the desulphurization process (2.49% m/m) than the traditional process (1.91% m/m). Overall, the implementation of a new esulphurization method would potentially increase the operation costs in 10.3%. At the light of these results, a combination of hydrometallurgical and pyro-metallurgical processes in the recycling of lead-acid batteries can be used to reduce the environmental im pact of these industries but would increase the operational costs of small lead recyclers.
Application of Poly-L-Lysine for Tailoring Graphene Oxide Mediated Contact Formation between Lithium Titanium Oxide LTO Surfaces for Batteries
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022) Borge-Durán, Ignacio; Grinberg, Ilya; Jose-Roberto, Vega-Baudrit; Nguyen, Minh Tri; Pereira-Pinheiro, Marta; Thiel, Karsten; Noeske, Paul-Ludwig Michael; Rischka, Klaus; Corrales, Yendry
Abstract. When producing stable electrodes, polymeric binders are highly functional materials that are effective in dispersing lithium-based oxides such as Li4Ti5O12 (LTO) and carbon-based materials and establishing the conductivity of the multiphase composites. Nowadays, binders such as polyvinylidene fluoride (PVDF) are used, requiring dedicated recycling strategies due to their low biodegradability and use of toxic solvents to dissolve it. Better structuring of the carbon layers and a low amount of binder could reduce the number of inactive materials in the electrode. In this study, we use computational and experimental methods to explore the use of the poly amino acid poly-L-lysine (PLL) as a novel biodegradable binder that is placed directly between nanostructured LTO and reduced graphene oxide. Density functional theory (DFT) calculations allowed us to determine that the (111) surface is the most stable LTO surface exposed to lysine. We performed Kubo–Greenwood electrical conductivity (KGEC) calculations to determine the electrical conductivity values for the hybrid LTO–lysine–rGO system. We found that the presence of the lysine-based binder at the interface increased the conductivity of the interface by four-fold relative to LTO–rGO in a lysine monolayer configuration, while two-stack lysine molecules resulted in 0.3-fold (in the plane orientation) and 0.26-fold (out of plane orientation) increases. These outcomes suggest that monolayers of lysine would specifically favor the conductivity. Experimentally, the assembly of graphene oxide on poly-L-lysine-TiO2 with sputter-deposited titania as a smooth and hydrophilic model substrate was investigated using a layer-by-layer (LBL) approach to realize the required composite morphology. Characterization techniques such as X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), Kelvin probe force microscopy (KPFM), scanning electron microscopy (SEM) were used to characterize the formed layers. Our experimental results show that thin layers of rGO were assembled on the TiO2 using PLL. Furthermore, the PLL adsorbates decrease the work function difference between the rGO- and the non-rGO-coated surface and increased the specific discharge capacity of the LTO–rGO composite material. Further experimental studies are necessary to determine the influence of the PLL for aspects such as the solid electrolyte interface, dendrite formation, and crack formation.
Bayesian estimates of the mean recharge elevations of water sources in the Central America region using stable water isotopes
(Elsevier, 2020) Avellano, L. Nicole; Good, Stephen; Sanchez-Murillo, Ricardo; Jarvis, Todd; NOONE, DAVID; Finkenbiner, Catherine
Abstract. Study region: Central America. Study focus: Knowledge of the mean recharge elevation (MRE) of water resources is important where water resources are vulnerable. The purpose of this study was to develop and apply a Bayesian approach which incorporates isotopic uncertainties and evaporative effects on isotopic compositions to determine the MRE of 680 surface water sources from Central America. Differences were assessed between results from our approach and those from other isotope-based methods that do not account for these factors. New hydrological insights for the region: Different MRE patterns were identified for Pacific and Caribbean basins, which were characterized by distinct isotopic signatures: 1) the Pacific slope had recharge occurring at higher elevations relative to the source mean catchment elevation (MCE) and 2) the Caribbean slope had recharge largely occurring at elevations lower than the MCE. These relationships were quantified: MREP = 1.072 (MCE) + 45.65 (Pacific: r2 = 0.93, error = 144 m); MREC = 0.9493 (MCE) – 28.24 (Caribbean: r2 = 0.83, error = 190 m). The MRE, surface water site elevation (SWSE), and MRE-SWSE differences were generally greater on the Pacific slope, which hosts most of the region’s population. Bayesian MRE estimates were on average lower than MREs obtained using other methods and may better approximate the actual (recharge-weighed) MRE, suggesting that the inclusion of isotopic uncertainties, evaporative corrections, and recharge likelihoods all positively effect MRE estimations.
Bio Refinery of Oily Wastes
(Juniper Publishers (Estados Unidos), 2018) Rojas Alfaro, Juan José; Fernández Araya, Luis Marcial; Redondo, Carlos; Jose-Roberto, Vega-Baudrit
Abstract. Many attempts have been made in order to establish a concept for biorefinery. The simplest way to do so is in an analogous way to the current oil refinery, where multiple fuels and products are manufactured from fossil source, but in the biorefinery scenario, biomass is converted into a range of biochemicals, materials and energy products in an industrial process.
Bio-inspired membranes for adsorption of arsenic via immobilized L-Cysteine in highly hydrophilic electrospun nanofibers
(Elsevier (Países Bajos), 2022) Picón, David; Torasso, Nicolás; Jose-Roberto, Vega-Baudrit; Cerveny, Silvina; Goyanes, Silvia
Abstract. Arsenic is a concern for its ubiquity in the environment and its accumulative and toxic properties. Water is often contaminated with this chemical, so developing simple, scalable, and green water treatment technologies is urgently needed. We show here that the ability of the L-Cysteine biomolecule to form complexes with arsenic inspires its use as a natural bio-inspired sorbent to develop advanced functional materials. We establish for the first time a way to chemically anchor L-Cysteine (L-Cys) inside highly hydrophilic nanofibers to create a membrane capable of lowering As(V) concentration below the WHO limit of 10 μg/L. A homogeneous precursor mixture of an aqueous solution of PVA and L- Cys (5 wt% and 10 wt% of L-Cys with respect to PVA) was electrospun to obtain a fibrous membrane. Successful immobilization of L-Cys within PVA nanofibers is achieved during heat treatment at 190 °C. It occurs through esterification reactions between the hydroxyl group on the PVA chain and the carboxylic acid on L-Cys. Arsenic sorption (as As (V)) was assessed by batch experiments in aqueous media and at a controlled pH range. The maximum removal efficiency was achieved at pH 7, supporting the formation of thiolate complexes as the primary mechanism for arsenic sorption. We show that L-Cys confinement makes arsenic diffusion inside the nanofibers a rate-limiting process in adsorption kinetics, following the pseudo first order equation. Overall, this work lishes a novel arsenic remediation strategy and encourages the research of nature-mimicking adsorbents and biodegradable polymers to develop functional materials in water remediation.
Bio-Inspired Proanthocyanidins from Blueberries’ Surface Coating Prevents Red Blood Cell Agglutination on Urinary Silicon-Based Catheters
(Multidisciplinary Digital Publishing Institute (MDPI) (Suiza), 2022) Orozco-Fernández, Viviana; Gómez-Solano, Sofía; Calderón, Jennifer; Jose-Roberto, Vega-Baudrit; Rischka, Klaus; Corrales, Yendry
Abstract. Thrombosis can cause the occlusion of implantable medical devices, leading to the rejection of the device and subsequent mortality. Thrombosis is primarily induced by red blood aggregation and coagulation. The administration of anticoagulant drugs is generally used as a treatment to avoid these processes. Adverse effects such as bleeding in the event of an anticoagulant overdose, osteoporosis associated with prolonged use, hypersensitivity, and hives have been reported. New strategies such as biomolecule surface functionalization have recently been studied to overcome these problems. In this study, we report a novel coating composed of polydopamine (PDA) and proanthocyanidins (PACs) from blueberry extract to avoid red blood aggregation in short-term use medical devices such as silicone catheters. We showed that PDA formed stable films on silicone surfaces and PACs could be immobilized on PDA layers using laccase as a catalyst. The PDA–PACs films decreased surface hydrophilicity, increased surface roughness, and decreased plasma protein adsorption. The films were stable in phosphate buffer saline (PBS) and cell culture media. Furthermore, red blood cell adsorption and aggregation decreased. These effects are attributed to changes in the membrane fluidity that influences adhesion, the steric hindrance of the layers, and the low adsorption of plasma proteins on the PAC layer.
Biodegradable plastics in aquatic ecosystems: latest findings, research gaps, and recommendations
(IOP Publishing (Reino Unido), 2022) Ribba, Laura; Lopretti, Mary; Montes de Oca-Vásquez, Gabriela; Batista, Diego; Goyanes, Silvia; Jose-Roberto, Vega-Baudrit
Abstract. The negative impact of plastic accumulation in aquatic ecosystems is a known and undeniable problem. However, while many of the scientific community’s countermeasures against such accumulation target the effects of the most common commodity plastics, the consequences of so-called ‘biodegradable’ plastics in those ecosystems are seldom discussed. After all, though their alleged biodegradability sustains the widespread belief that they are harmless to the environment, because a material’s fate determines its classification as biodegradable or not, many plastics classified as biodegradable do not in fact meet the required norms and standards of biodegradability in aquatic ecosystems. Furthermore, during the past five years, the scientific community has shown that the degradation of such plastics can generate bio-microplastics that have effects similar to or worse than those of conventional microplastics (MPs). Against that background, this review details the latest findings regarding how biodegradable plastics can influence aquatic ecosystems and thus cause adverse health effects in living organisms and/or act as vectors of chemical pollutants. Beyond that, it identifies the key aspects of such trends to be investigated in greater depth, including the need to consider a wider variety of biodegradable plastics and to develop systematic methods that allow quantifying and identifying the remains of those pollutants in living species. Other aspects worth considering include the arrival and mobilisation dynamics of MPs in oceans. The ways in which small animals fed by filtering (e.g. red crabs and other zooplankton organisms) move MPs through the water column and into food webs also merit attention, for those MPs are ingested by numerous species at different trophic levels, at which point bioaccumulation in tissues has to be considered as a factor of toxicity. This review closes with a series of recommendations and perspectives for future studies on biodegradable plastics in aquatic ecosystems.
Biosensor based on the directly enzyme immobilization into a gold nanotriangles/conductive polymer biocompatible coat for electrochemical detection of Chlorpyrifos in water
(Wiley Periodicals, Inc., 2019) Ramírez Sánchez, Karla; Alvarado Hidalgo, Fernando; Zamora-Sequeira, Roy; Sáenz-Arce, Giovanni; Rojas Carrillo, Oscar; Avendaño Soto, Esteban Damian; Ruepert, Clemens; Mena, Freylan; Starbird-Perez, Ricardo
Abstract. Organic conductive polymers have been widely used as active layers in bioelectronic devices. In this work, a novel approach to entrap enzymes directly into the conductive active layer is described, using a polysaccharide as a surfactant. The surfactant allowed the electropolymerization from a micellar media and it acted as a doping agent in the conductive polymer. Gold nanotriangles were added to the matrix in order to enhance the enzymatic product quantification. The composition and oxidation state of the biocompatible conductive layer were confirmed by infrared spectrophotometric and Raman studies. Meanwhile, the gold nanotriangles presence, distribution and electrochemical activity were studied by transmission electron microscopy, atomic force microscopy, dynamic light scattering and cyclic voltammetry techniques. The inhibition of the enzyme, due to the presence of pesticides, was used to electrochemically quantify their concentration in real water samples. The concentration was confirmed by gas and liquid chromatography. Therefore, this novel composite active layer allows building a biosensor with suitable performance for an early warning in environmental control, especially in countries highly impacted by agricultural activities.
Biosíntesis de dextranos de alto peso molecular mediante la inoculación con Leuconostoc mesenteroides, var. mesenteroides (ATCC 10830) de jugos residuales de la agroindustria de la piña: síntesis y caracterización de hierro-dextranos
(Laboratorio Tecnológico del Uruguay (LATU) (Uruguay), 2012) Jose-Roberto, Vega-Baudrit; Sibaja Ballestero, María del Rosario; Lopretti, Mary
Resume. En este trabajo se muestran los estudios realizados para obtener dextranos a partir de desechos de la agroindustria de piña. La fermentación se llevó a cabo en un biorreactor (10 L), se inoculó con un cultivo de Leuconostoc mesenteroides, var. mesenteroides (ATCC 10830). Se centrifugó y se precipitó y purificó con etanol. Fue caracterizado por medio de viscosidad, peso molecular y grupos funcionales por espectroscopía infrarroja. Este dextrano fue tratado con el fin de obtener hierro-dextranos.
Botos Lagoon, Poás Volcano National Park, Costa Rica – Consumer drones in professional research
(Advanced UAV, 2023) Godfrey, Ian; Sibaja, José; Martínez Cruz, Maria; Avard, Geoffroy; Meghraoui, Khadija
The International Union of Geological Sciences designated the Poás Volcano National Park in Costa Rica one of the top 100 sites for geological importance in the world. This was announced on the World Geological Heritage list which includes sites from 56 additional countries. The Poás Volcano stands out next to Mount Everest in Nepal, the Grand Canyon in the United States and the caldera of Santorini in Greece. The Poás Volcano National Park is an active volcanic crater visible from the crater rim and is one of the most visited National Parks in Costa Rica. Consumer drones were used at the Poás Volcano National Park in particular at the Botos Lagoon for observational research and environmental monitoring for several conservational applications assisted by the use of drones. UAS have been periodically used by the Laboratory of Atmospheric Chemistry Universidad Nacional LAQAT-UNA for monitoring the Botos Lagoon for geological fluctuations. Economically priced drone systems have now become common pieces of field work equipment for volcanologists. Most importantly they offer the opportunity to access dangerous difficult to reach areas of the volcano and allow for the collection of data on the otherwise inaccessible areas. By compiling all of this data together in a collective analytical survey of the Poás Volcano including the Botos Lagoon located in the prehistorical dormant crater, much valuable data can be brought to the scientific community for increased understanding of the Poás Volcano National Park and its importance to the nation.
Calidad del agua de los ríos de la microcuenca IV del Río Virilla
(Universidad Nacional (Costa Rica), 2010) Leandro, Hugo; Coto, Juana María; Salgado, Viviana
En la evaluación de la calidad del agua de los cauces de los Ríos Tibás, Lajas, Tranqueras y Tures de la Microcuenca IV del Río Virilla se aplicaron dos índices basados en parámetros físicos, químicos y bacteriológicos con el fin de brindar recomendaciones para la gestión y el uso del recurso hídrico. Los índices aplicados fueron el Índice de Calidad de la Fundación Nacional de Sanidad de los Estados Unidos de América (ICAFNS) y el Índice del Sistema Holandés de Valoración de la Calidad del Agua. Se realizaron tres muestreos: en la época lluviosa en setiembre del 2004, transición lluviosa-seca en diciembre del 2004 y en la época seca en febrero del 2005; en 7 puntos: uno ubicado en el Río Tranqueras, otro en el Río Lajas y cinco en el Río Tibás. También, se determinó cualitativamente la vulnerabilidad de los puntos de muestreo. Se concluyó que en los puntos superiores la contaminación está asociada a la escorrentía superficial y en los inferiores a los efectos de fuentes de contaminación puntuales y no puntuales. Una adecuada gestión de la microcuenca debe incluir acciones de protección y conservación de suelos en los puntos superiores, mientras que en los inferiores se requieren acciones de remediación y posterior protección, particularmente un manejo adecuado de las aguas negras.
Cardanol: Una Alternativa Ecológica para Potenciales Aplicaciones en la Industria de los Polímeros
(Universidad del País Vasco (España), 2019) Herrera Báez, Randall; Vargas Jiménez, Christian; Herrera Ubau, Mario; Jose-Roberto, Vega-Baudrit
Resumen. Teniendo en cuenta la forma en que se llevan a cabo los procesos dentro del sector industrial desde hace varios años, es claro destacar el consumo excesivo de recursos naturales no renovables y el uso de materias primas tóxicas para la elaboración de productos. Debido a esto, ha surgido una tendencia en la cual se fomenta el uso inteligente de los recursos, y además, la sustitución de materiales contaminantes y dañinos para la salud humana por otros que presentan características más apropiadas. El cardanol aparece como una alternativa valiosa que resuelve los problemas descritos anteriormente. Este se obtiene a partir del líquido de la cáscara de anacardo (CNSL), el cual es un subproducto del procesamiento de las semillas de la fruta, que generalmente se desecha. Este compuesto, debido a su estructura fenólica con un sustituto meta sustituido de cadena alifática, resulta ser una materia prima muy versátil que puede sufrir una gran variedad de reacciones químicas para formar intermediarios importantes en los procesos de síntesis de resinas, medicamentos, surfactantes, entre otros. La presente revisión bibliográfica, tiene como objetivo, analizar desde un punto de vista de la aplicación, el potencial del cardanol como materia prima sostenible y no tóxica, en la elaboración de diferentes productos industriales.
Cellulose Nanofibers as Functional Biomaterial from Pineapple Stubbles via TEMPO Oxidation and Mechanical Process
(Springer (Alemania), 2022) Araya‑Chavarría, Kenly; Rojas, Ruth; RAMÍREZ-AMADOR, KARLA; Sulbaran Rangel, Belkis; Rojas, Orlando; ESQUIVEL, MARIANELLY
Abstract. The pineapple fruit when harvested generates a large amount of residual biomass; this biomass can be used to generate value-added products such as cellulose nanofibers. This study was focused on the isolation of CNF from pineapple leaves after oxidation pretreatment with 2,2,6,6-tetramethylpireridine-1-oxyl, followed by mechanical deconstruction of the fibers via combination of grinding and microfluidization process. One and two microfluidization passes were applied to bleached and unbleached fibers, respectively. The implications of these findings are that during the production process it is possible to reduce the amount of chemicals needed for bleaching and the energy involved in the mechanical microfluidization process. Such process yielded corresponding fibril lengths and widths in the range of 481–746 nm and 16–48 nm. The respective electrostatic charges, as measured by zeta potentials, were −41 mV and −31 mV. As expected, the CNF crystallinity was higher than that of the starting material, especially for the cellulose. However, the thermal stability was reduced, showing two degradative processes due to the chemical modification of the fibers. The CNF produced from pineapple leaves has a potential to be used like biomaterial in diverse applications while representing a viable alternative to producers, which face serious environmental and health challenges given the large volume of biomass that is otherwise left in the fields as waste.
Chemical and Antioxidant Charaterization of Native Corn Germplasm from Two Regions of Costa Rica: A Conservation Approach
(Wiley (Estados Unidos), 2020) Syedd-León, Randall; Orozco Rodríguez, Rafael; Álvarez, Victor; Carvajal-Miranda, Yendry; Rodríguez, Gerardo
The cultivation of native corn has decreased in favor of the cultivation of improved commercial corn varieties. This study seeks to evaluate the antioxidant and antibacterial potential of 36 samples of native corn germplasm from the Brunca (BR) and Chorotega (CR) regions of Costa Rica. The main parameters of comparison were the composition of antioxidant compounds, antiradical activity, and microbicidal effect. The total amount of polyphenols in the germplasm (120 mg GAE/100 g d.w.) was not related to the regions from which the samples were obtained. The overall average for antioxidant capacity was 21.20 μmol TE/g d.w. Accessions from the CR region had higher antioxidant capacity. Anthocyanin content was higher in purple accessions and undetectable in white germplasm. Antioxidant capacity was statistically related to polyphenols content (r = 0.714, p < 0.01). The most promising corn accessions in terms of nutraceutical value came from the CR region.
Chemical and functional characterization of antimicrobial metabolites isolated from ascidian Rhopalaea Birkelandi
(Universidad Nacional (Costa Rica), 2011-12) Cordero, Maribel; Borbón, Henry; Román, Félix R.; Morrel, Luis; Víquez, Rigoberto; Villegas, Luis R.; Soto, Roy; Vega, Ileana
Marine ecosystems have a very large diversity of resources, most of them still partially unknown, and a few others exploited for development of new industrial and toxicological products. The objective of this investigation was to determine whether the acetone extract of the ascidia R. birkelandi from the Pacific coast of Costa Rica showed qualitative antimicrobial activity against the S. aureus bacteria and the G. candidum fungus, and to verify their main secondary metabolites in the active extract using chromatographic and spectroscopic techniques. Ascidians were collected at Tambor, Guanacaste, Costa Rica, between December 2007 and March 2008. Activity against the Gram positive bacteria and fungi was evaluated using ethanolic (95%) and acetonic extracts. Both extracts showed activity against G. candidum; however, only the acetonic extract showed activity against S. aureus. A coumarin and a hydroxyanthraquinone were isolated from a crude extract of R. birkelandi as metabolites present in the active fraction. Purification and isolation were performed by chromatographic techniques and solid phase extraction. Structural information was obtained by spectroscopic analyses: Ultraviolet (UV-Visible), Fourier Transform Infrared (FT-IR), Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS), Gas Chromatography Mass Spectrometry (GC/MS), Proton Nuclear Magnetic Resonance (1HNMR), and Carbon-13 Magnetic Resonance (13C-NMR). Further studies are recommended for characterization and quantification of the active components of this extract and the possible elucidation of the mechanisms of action.

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