Hidrólisis de lactosa con [beta]-galactosidasas de "Kluyveromyces fragilis" y de "Escherichia coli"

En este trabajo se estudian fenómenos existentes en las reacciones enzimáticas, tanto cuando la enzima actúa como catalizador homogéneo como cuando está inmovilizada y, por tanto, actúa como catalizador hetepogéneo. Los fenómenos abordados han sido: las reacciones de hidrólisis de lactosa y de ONPG con las dos enzimas, en disolución e inmovilizadas; la difusión de los sustratos en el interior del soporte donde se encuentra inmovilizada la enzima y la desactivación de la enzima, en disolución e inmovilizada. Se ha elegido como reacción a estudiar la hidrólisis de galactósidos con enzimas beta-Galactosidasas, utilizando las dos enzimas y los dos sustratos mencionados. Se han determinado las condiciones adecuadas para llevar a cabo las distintas reacciones y se ha discriminado un modelo cinético representativo de cada sistema reaccionante. En el estudio de la difusión de los sustratos en el soporte, se ha determinado la distribución de la enzima de K. fragilis en dicho soporte y el coeficiente de difusión efectivo en presencia y ausencia de reacción.

“La frontera de Perpiñán”. Nuevos datos sobre la primera guerra del Rosellón (1495-1499)

Presentación y estudio de nuevas fuentes documentales sobre la guerra entre los Reyes Católicos y Carlos VIII de Francia en Nápoles y el Rosellón, entre 1495 y 1499. Evolución del conflicto y análisis detallado de las grandes movilizaciones de tropas hechas en Castilla para la defensa del Rosellón, construcción de fortalezas, en especial Salses, y abastecimiento de cereales desde Andalucía, mediante el empleo masivo de recursos hacendisticos castellanos

THE ROLE OF THE RETAILERS IN CAUSE-RELATED MARKETING: A REFERENCE TO THE SPANISH CASE

Cause-Related Marketing (CRM) is one of the most relevant Corporate Social Responsibility (CSR) initiatives nowadays. Its most important characteristic is that corporate donation is conditioned by sales, that is, CRM ultimately depends on consumer behavior. In this paper, we focus on CRM programs and its application in a specific industry: distribution sector. Thus, our aim is to understand the fundamental features or the practice of these programs in the distribution sector in Spain, to study the role played by retailers and their possible influence on the consumer behavior, so that companies can better design these campaigns and achieve greater success. Hence, the paper is organized as follows. First, we review the CRM conceptual framework in which the theoretical development of this work is based. Secondly, and from a list of companies associated to the National Association of Large Distribution Companies (ANGED), the most representative retail association in Spain, we observe the Spanish situation and analyze the main campaigns carried out by these retailers during the last years. This information was completed consulting each retailer´s website, asking them for additional information by email, and with a general internet search. After that, we present and discuss the main results, and summarize the most relevant conclusions, as well as the theoretical contribution and managerial implications. One of the most important findings shows the retailer´s influence on consumer behavior and the key role of the retailers in the success of CRM programs. Finally, we also include possible limitations and further research.</p

Development of a Simple and Robust Kinetic Model for the Production of Succinic Acid from Glucose Depending on Different Operating Conditions

Succinic acid (SA) is one of the main identified biomass-derived chemical building blocks. In this work we approach the study of its production by Actinobacillus succinogenes DSM 22257 from glucose, focusing on the development and application of a simple kinetic model capable of representing the evolution of the process over time for a great diversity of process variables key to the production of this platform bio-based chemical: initial biomass concentration, yeast extract concentration, agitation speed, and carbon dioxide flow rate. All these variables were studied experimentally, determining the values of key fermentation parameters: titer (23.8–39.7 g·L −1 ), yield (0.59–0.72 gSA·gglu −1 ), productivity (0.48–0.96 gSA·L −1 ·h −1 ), and selectivity (0.61–0.69 gSA·gglu −1 ). Even with this wide diversity of operational conditions, a non-structured and non-segregated kinetic model was suitable for fitting to experimental data with high accuracy, considering the values of the goodness-of-fit statistical parameters. This model is based on the logistic equation for biomass growth and on potential kinetic equations to describe the evolution of SA and the sum of by-products as production events that are not associated with biomass growth. The application of the kinetic model to diverse operational conditions sheds light on their effect on SA production. It seems that nitrogen stress is a good condition for SA titer and selectivity, there is an optimal inoculum mass for this purpose, and hydrodynamic stress starts at 300 r.p.m. in the experimental set-up employed. Due to its practical importance, and to validate the developed kinetic model, a fed-batch fermentation was also carried out, verifying the goodness of the model proposed via the process simulation (stage or cycle 1) and application to further cycles of the fed-batch operation. The results showed that biomass inactivation started at cycle 3 after a grace period in cycle 2.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEComunidad de MadridMinisterio de Ciencia e Innovaciónpu

O turismo accesible como exemplo de responsabilidade social nas empresas e destinos turísticos. O caso de Lousã (Portugal)

La responsabilidad social, entendida como una nueva cultura empresarial basada en la gestión ética, puede servir como cauce para mejorar la competitividad y la reputación de las empresas turísticas, respondiendo así a las crecientes demandas de la sociedad en general y de los consumidores en particular. En este contexto surge el concepto de “turismo sostenible”, que trata de ofrecer una experiencia digna y enriquecedora al turista, al mismo tiempo que trata de responder a la creciente preocupación por los impactos negativos del turismo en las áreas de destino. El “turismo accesible” se encuadra en este marco, una modalidad de oferta turística integrada que permite a todos disfrutar de experiencias turísticas “sin barreras”. Esta modalidad de turismo no sólo permite a las empresas una especialización (y, por tanto, una mejor satisfacción del mercado de personas con discapacidad), sino también les permite mostrar una imagen más humana, conseguir una reputación de empresa turística socialmente responsable,lo cual puede constituir una importante ventaja competitiva. En este artículo nos centramos en el caso de Lousã, un municipio portugués que ha apostado por el turismo accesible como estrategia de cualificación y diferenciación del destino, como estrategia de desarrollo y posicionamiento en un entorno crecientemente competitivo. Esta apuesta ha dinamizado numerosas iniciativas y nuevos caminos de colaboración entre diversos agentes (públicos y privados), ofreciendo oportunidades muy interesantes en un contexto de desarrollo de los territorios que busca no excluir a nadie.Social responsibility, understood as a new business culture based on ethical management, may serve as a route for improving competitiveness and the reputation of tourism companies, thus responding to the growing demands of society in general and of consumers in particular. The concept of “sustainable tourism” arises within this context. It aims to offer the tourist a worthy and enriching experience, and at the same time to respond to the growing concern about the negative impact of tourism on the destination areas. “Accessible tourism” fits within this framework, a type of integrated tourism which allows everybody to enjoy tourism experiences “without barriers”. This type of tourism not only allows companies a specialisation (and, therefore, better satisfaction of the disabled person market), but it also allows them to show a more humane image and to achieve a reputation as a tourism company which is socially responsible, which may constitute a significant competitive advantage. This article focuses on the case of Lousã, a Portuguese town committed to accessible tourism as a strategy for qualifying and differentiating the destination, as a strategy for developing and positioning in an increasingly competitive environment. This commitment has revitalised numerous initiatives and new types of collaboration between different agents (public and private), offering very interesting opportunities in the context of developing territories which aim not to exclude anybody.A responsabilidade social, entendida como unha nova cultura empresarial baseada na xestión ética, pode servir como canle para mellorar a competitividade e a reputación das empresas turísticas, en resposta ás crecentes demandas da sociedade en xeral e dos consumidores en particular. Neste contexto xorde o concepto de turismo sustentable, que trata de ofrecerlles unha experiencia digna e enriquecedora aos turistas e, asemade, responder á crecente preocupación polos impactos negativos do turismo nas áreas de destino. O turismo accesible encádrase neste marco como unha modalidade de oferta turística integrada que lles permite a todas as persoas gozar de experiencias turísticas «sen barreiras». Esta modalidade de turismo non só fai posible a especialización das empresas (e, por tanto, que satisfagan mellor o mercado de persoas con minusvalías), mais tamén estas mostraren unha imaxe máis humana e conseguiren unha reputación de empresa turística socialmente responsable, o cal pode constituír unha importante vantaxe competitiva. Neste artigo centrámonos no caso de Lousã, un municipio portugués que apostou polo turismo accesible como estratexia de cualificación e diferenciación do destino, como estratexia de desenvolvemento e posicionamento nun ámbito crecentemente competitivo. Esta aposta dinamizou numerosas iniciativas e novos camiños de colaboración entre diversos axentes públicos e privados, as cales lle permiten ofrecer oportunidades moi interesantes nun contexto de desenvolvemento dos territorios que busca non excluír a ninguén

Immobilization-Stabilization of β-Glucosidase for Implementation of Intensified Hydrolysis of Cellobiose in Continuous Flow Reactors

Cellulose saccharification to glucose is an operation of paramount importance in the bioenergy sector and the chemical and food industries, while glucose is a critical platform chemical in the integrated biorefinery. Among the cellulose degrading enzymes, β-glucosidases are responsible for cellobiose hydrolysis, the final step in cellulose saccharification, which is usually the critical bottleneck for the whole cellulose saccharification process. The design of very active and stable β-glucosidase-based biocatalysts is a key strategy to implement an efficient saccharification process. Enzyme immobilization and reaction engineering are two fundamental tools for its understanding and implementation. Here, we have designed an immobilized-stabilized solid-supported β-glucosidase based on the glyoxyl immobilization chemistry applied in porous solid particles. The biocatalyst was stable at operational temperature and highly active, which allowed us to implement 25 °C as working temperature with a catalyst productivity of 109 mmol/min/gsupport. Cellobiose degradation was implemented in discontinuous stirred tank reactors, following which a simplified kinetic model was applied to assess the process limitations due to substrate and product inhibition. Finally, the reactive process was driven in a continuous flow fixed-bed reactor, achieving reaction intensification under mild operation conditions, reaching full cellobiose conversion of 34 g/L in a reaction time span of 20 min.Comunidad de MadridMINECODepto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu

Modeling the Succinic Acid Bioprocess: A Review

Succinic acid has attracted much interest as a key platform chemical that can be obtained in high titers from biomass through sustainable fermentation processes, thus boosting the bioeconomy as a critical production strategy for the future. After several years of development of the production of succinic acid, many studies on lab or pilot scale production have been reported. The relevant experimental data reveal underlying physical and chemical dynamic phenomena. To take advantage of this vast, but disperse, kinetic information, a number of mathematical kinetic models of the unstructured non-segregated type have been proposed in the first place. These relatively simple models feature critical aspects of interest for the design, control, optimization and operation of this key bioprocess. This review includes a detailed description of the phenomena involved in the bioprocesses and how they reflect on the most important and recent models based on macroscopic and metabolic chemical kinetics, and in some cases even coupling mass transport.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu

Lipozyme® TL IM Biocatalyst for Castor Oil FAME and Triacetin Production by Interesterification: Activity, Stability, and Kinetics

Global climate change and present geopolitical tensions call for novel, renewable, and, ideally, sustainable resources and processes that, in the end, will be integrated in the natural cycles of carbon and water, progressively replacing non-renewable feedstocks. In this context, the production of biofuels and, in consequence, of biodiesel plays a notable role. This work is focused on the production of fatty acid methyl esters (FAME) from castor oil, an abundant non-edible oil, using a sustainable technology approach based on industrial lipases and methyl acetate as a methylating reagent to reduce biocatalyst inactivation. We have selected a stable industrial enzyme preparation to determine its suitability for FAME production: Lipozyme® TL IM (an inexpensive lipase from Thermomyces lanuginosus immobilized by agglomeration in silica gel). Several operational variables affecting the enzyme activity have been studied: methanol excess (6:1 to 13:1), temperature (from 40 to 60 °C), and enzyme concentration (10 and 30% w/w). At all temperatures and reagent ratios, we have also tested the enzyme stability for six cycles, showing its low to negligible inactivation under operational conditions. Finally, a novel multivariable kinetic model has been proposed and fitted to experimental data obtained in a wide experimental range for the first time, showing that direct and reverse in-series reactions are present. We have estimated the values of the kinetic constants and their standard errors, and goodness-of-fit parameters, observing that the kinetic model fitted very reasonably to all retrieved experimental data at the same tim

Kinetic modelling of 2,3-butanediol production by Raoultella terrigena CECT 4519 resting cells: Effect of fluid dynamics conditions and initial glycerol concentration

Biodiesel-derived glycerol was biologically converted to 2,3-butanediol, an organic compound with multiple industrial applications. Recent studies showed that Raoultella terrigena CECT 4519 is an effective biocatalyst for the bioprocess under conventional growing conditions. In the present work, a novel biocatalyst composed by R. terrigena resting cells was evaluated for the first time. Fluid dynamic conditions has been optimized to maximize 2,3-butanediol production in terms of titre, yield, and selectivity. Regarding the effect of initial glycerol concentration in batch runs, no substrate inhibition was detected in the studied conditions (concentrations between 45 and 250 g/L were used). Employing pure glycerol as carbon source, 82.0 g/L 2,3-butanediol titre was achieved, whereas 76.5 g/L were reached using raw glycerol. These numbers involve an achieved yield respect to maximal theoretic yield of 79% and 77%, respectively. A successful kinetic modelling of the bioprocess was developed and it is able to describe both the evolution of concentrations of relevant components with time and the rates calculated at experimental time values. Estimated specific 2,3-butanediol production rate was 0.034 g2,3-BDO/gX·h, while the estimated empirical pseudo-stoichiometric coefficient glycerol/2,3-butanediol was 2.52 gGly/g2,3-BDO. The obtained results showed that R. terrigena resting cells is a promising biocatalyst, which provides new opportunities for developing and scaling-up glycerol biorefineries

Intensification of oxygen-dependent biotransformations catalyzed by immobilized enzymes

Oxidative biotransformations find a prominent role in the fine chemical industry and the valorization of renewable feedstocks. Implementation of oxygen-dependent reactions faces some challenges across scales and at different levels of development. First, the fruitful development of enzyme candidates and identification of reaction possibilities is not in consonance with the implementation in process engineering. Second, reaction engineering faces a complex interplay of reaction kinetic, oxygen transfer and process stability. Third, given the advances in synergic fields such as molecular biology, chemistry, material sciences, and (micro)process engineering, an interdisciplinary assembly from a consistent discipline around heterogeneous biocatalyst engineering would be of strategic value. We show advances in design of active and robust immobilized enzyme catalysts to be applied in (continuous) intensified processes. A framework based on the joint design of a catalyst and reactor will be discussed for the design and optimization of the catalysts and biotransformations involved