Extracción biotecnológica de quitina para la producción de quitosanos: caracterización y aplicación

La quitina es uno de los biopolímeros más abundantes en la naturaleza que junto con el quitosano, su principal derivado, presentan diversas aplicaciones. Los desechos de camarón representan una fuente de quitina que permite la valorización de un compuesto que por lo general es responsable de un problema ambiental. La quitina y el quitosano son producidos industrialmente mediante proceso termo químico. Sin embargo estos métodos generan desechos corrosivos, gasto de energía y agua y la producción de biopolímeros con cierto grado de depolimerización. El objetivo principal de este trabajo fue el estudio de factores que afectan los procesos de desmineralización, desproteinización y desacetilación de desperdicios de camarón para obtención de quitina y quitosano mediante bacterias lácticas y enzimas, la caracterización de los productos obtenidos y su aplicación como agente fungistáticos. El estudio de la temperatura de fermentación de los desechos de camarón permitió determinar condiciones óptimas para la remoción de proteínas y minerales (Temperatura entre 30 - 40°C). El modelo polinomial de segundo orden obtenido, proporcionó una herramienta para la predicción de la desmineralización en función de la temperatura y la acidez y la determinación de valores mínimos y máximos de crecimiento de las bacterias lácticas. Las cinéticas de desmineralización y desproteinización durante la fermentación de desechos de camarón Litopenaeus vanameii, mostraron la posibilidad de acortar el tiempo de fermentación al obtener más del 90 % de desmineralización y desproteinización a las 96h del proceso. La caracterización estructural de los productos obtenidos, indicó que el proceso biológico permite la conservación de pesos moleculares elevados. La determinación de parámetros estructurales durante la desacetilción química de quitinas biológicas indicó la conservación del peso molecular en los productos de desacetilación. Características útiles para aplicaciones posteriores. La producción de enzimas chitin desacetiladas, las cuales catalizan la hidrólisis de N- desacetilación de la quitina, resultado ser una alternativa al método químico de reacción. El hongo Colletotrichum gloeosporioides mostró la capacidad de producir chitin desacetilasas, que al ser parcialmente purificadas permitieron la determinación de condiciones de desacetilación. La aplicación de las enzimas parcialmente purificadas en quitinas y quitinas modificadas química y físicamente mostró hasta un 20% de disminución en el grado de acetilación de los biopolímeros con ligera pérdida en el peso molecular. Por último, la determinaciones in vitro del efecto de quitosanos con diferentes pesos moleculares y grados de acetilación, mostraron que el quitosano de peso molecular medio (400 g.mol-1) inhibió al hongo P. digitatum durante la etapa de germinación de esporas, y que en combinación con un agente de biocontrol como la levadura (Pichia guillermondii) la inhibición se observa durante la etapa de crecimiento radial. La evaluación de temperatura y determinación de cinéticas de desmineralización y desproteinización durante el proceso de fermentación, permitieron la optimización del proceso. Las quitinas biológicas desacetiladas químicamente mostraron la conservación del peso molecular y el índice de cristalinidad. El método enzimático de desacetilación mostró disminución del grado de acetilación con menor reducción en el peso molecular al comparar con quitinas obtenidas por métodos químicos. El grado de acetilación y peso molecular de los quitosanos obtenidos por métodos químicos mostraron influenciar en la actividad antimicrobiana del mismo.Chitin is one of the most abundant biopolymers on earth together and with the chitosan, its main derivative, they have shown several applications. Shrimp wastes represent a source of chitin that allows recovery of this compound and this process resolves an environmental problem. Chitin and chitosan are produced industrially by a thermo chemical process. However, these methods generate corrosive side products, high energy and water consumption and the production of biopolymers with a high degree of depolymerization. The main objective of this work was the study of the factors that affect the demineralization, deproteinization and deacetylation process of shrimp waste for chitin and chitosan production by the use of lactic bacteria and enzymes, the characterization of the products obtained and their application as a fungistatic agent. The study of the temperatures in the fermentation allowed the determination of the optimal conditions for the removal of proteins and minerals (temperature between 30 - 40 ° C). The polynomial model of second order obtained, provided a tool for the prediction of demineralization as a function of temperature and acidity. The growth of lactic acid bacteria at different temperatures enabled the determination of minimum and maximum growth temperatures. The kinetics of demineralization and deproteinization during fermentation of shrimp waste Litopenaeus vanameii have shown the possibility of diminish the fermentation time to attain above 90% of demineralization and deproteinization after 96h. Structural characterization of the products obtained, indicated that the biological process allows the preservation of high molecular weight of the macromolecule. The determination of structural parameters during the chemical desacetilación of chitin, showed the conservation of the macromolecular structure of biological products after deacetylation. These are important features for further applications. Chitin deacetylases, proved to be an alternative to the chemical deacetylation method. The fungus Colletotrichum gloeosporioides showed the ability to produce chitin deacetylases that after partially purification allowed the determination of optimum deacetylation conditions. The application of enzymes in partially purified chitin and chemically and physically modified chitins showed a decrease up to 20% in the degree of acetylation of the biopolymers, with a slight loss in molecular weight. Finally, in vitro determinations of the effect of chitosan with different molecular weights and degrees of acetylation showed that an average molecular weight chitosan (400 g.mol-1), inhibited the fungus P. digitatum during the stage of spore germination. The chitosan in combination with a biocontrol agent such as yeast (Pichia guillermondii) showed an inhibition in the radial growth phase. The evaluation of temperature and the kinetics of demineralization and deproteinization during the fermentation process, allowed the optimization of the process. Biological chemically deacetylated chitins, showed conservation in the molecular weight and crystallinity index. The enzymatic method indicated a decreased on the deacetylation degree, with a low reduction in molecular weight compared with chemical deacetylated chitins. The degree of acetylation and molecular weight of chitosans influence the antimicrobial activity

Extraction biotechnologique de la chitine pour la production de chitosane : caractérisation et application

The chitin is one of the most abundant biopolymers in biomass. Its main industrial derivative is the chitosan. These two polysaccharides present an increasing interest thanks to their various interesting physicochemical and biological properties. Their potential applications concern diverse fields as the pharmacy, medicine, food industry and agriculture. Despite numerous advances in methods for the chemical production of chitin and chitosan, the use of concentrated solutions of acids and alkaline bases presents the disadvantage to generate large amounts of toxic wastes. Recently, biotechnological methods of chitin extractions have been proposed as an alternative to chemical methods. In this context, the main objective of this work was to develop a biotechnological process for the extraction of chitin from crustacean shells using lactic acid bacteria and enzymes. For this purpose, factors influencing reactions involved in the extraction, i.e. the demineralization, deproteinization and N-deacetylation, were studied considering the physicochemical characteristics (molecular weight and degree of N-acetylation) of chitin and chitosan produced. The recovery of extraction side products such as proteins and pigments has also been considered in this project, as well as the evaluation of various chitosans prepared by this process as fungistatic agents.La chitine est l’un des biopolymères les plus abondants dans la biomasse. Son principal dérivé industriel est le chitosane. Ces deux polysaccharides présentent un intérêt croissant en raison de leurs nombreuses propriétés physico-chimiques et biologiques remarquables. Leur utilisation en tant que matériaux est potentiellement intéressante dans de nombreux domaines tels que la pharmacie, la médecine, l’industrie alimentaire et l'agriculture. Malgré de nombreuses avancées dans les méthodes chimiques de production de la chitine et du chitosane, l'utilisation de solutions concentrées d'acides et de bases alcalines présente le désavantage de générer de grandes quantités d’effluents toxiques. Récemment, des méthodes d'extraction de la chitine par biotechnologie ont été proposées comme une alternative aux méthodes chimiques. Dans ce contexte, l'objectif principal de ce travail a été de développer un procédé biotechnologique d’extraction de la chitine à partir de carapaces de crustacés à l’aide de bactéries lactiques et d’enzymes. A cette fin, les facteurs influençant les réactions mises en jeu au cours de l’extraction, telles que la déminéralisation, la déprotéinisation et la N-désacétylation ont été étudiés en considérant les caractéristiques physico-chimiques des chitines et chitosanes ainsi obtenus. Ces caractéristiques sont principalement les masses molaires moyennes et le degré de N-acétylation. Ce travail s’est également intéressé à la valorisation des sous-produits d’extraction (protéines, pigments…) et aux applications potentielles des différents chitosanes préparés, notamment comme agents fongistatiques

Extraction biotechnologique de la chitine pour la production de chitosane : caractérisation et application

The chitin is one of the most abundant biopolymers in biomass. Its main industrial derivative is the chitosan. These two polysaccharides present an increasing interest thanks to their various interesting physicochemical and biological properties. Their potential applications concern diverse fields as the pharmacy, medicine, food industry and agriculture. Despite numerous advances in methods for the chemical production of chitin and chitosan, the use of concentrated solutions of acids and alkaline bases presents the disadvantage to generate large amounts of toxic wastes. Recently, biotechnological methods of chitin extractions have been proposed as an alternative to chemical methods. In this context, the main objective of this work was to develop a biotechnological process for the extraction of chitin from crustacean shells using lactic acid bacteria and enzymes. For this purpose, factors influencing reactions involved in the extraction, i.e. the demineralization, deproteinization and N-deacetylation, were studied considering the physicochemical characteristics (molecular weight and degree of N-acetylation) of chitin and chitosan produced. The recovery of extraction side products such as proteins and pigments has also been considered in this project, as well as the evaluation of various chitosans prepared by this process as fungistatic agents.La chitine est l’un des biopolymères les plus abondants dans la biomasse. Son principal dérivé industriel est le chitosane. Ces deux polysaccharides présentent un intérêt croissant en raison de leurs nombreuses propriétés physico-chimiques et biologiques remarquables. Leur utilisation en tant que matériaux est potentiellement intéressante dans de nombreux domaines tels que la pharmacie, la médecine, l’industrie alimentaire et l'agriculture. Malgré de nombreuses avancées dans les méthodes chimiques de production de la chitine et du chitosane, l'utilisation de solutions concentrées d'acides et de bases alcalines présente le désavantage de générer de grandes quantités d’effluents toxiques. Récemment, des méthodes d'extraction de la chitine par biotechnologie ont été proposées comme une alternative aux méthodes chimiques. Dans ce contexte, l'objectif principal de ce travail a été de développer un procédé biotechnologique d’extraction de la chitine à partir de carapaces de crustacés à l’aide de bactéries lactiques et d’enzymes. A cette fin, les facteurs influençant les réactions mises en jeu au cours de l’extraction, telles que la déminéralisation, la déprotéinisation et la N-désacétylation ont été étudiés en considérant les caractéristiques physico-chimiques des chitines et chitosanes ainsi obtenus. Ces caractéristiques sont principalement les masses molaires moyennes et le degré de N-acétylation. Ce travail s’est également intéressé à la valorisation des sous-produits d’extraction (protéines, pigments…) et aux applications potentielles des différents chitosanes préparés, notamment comme agents fongistatiques

Activity of chitin deacetylase from Colletotrichum gloeosporioides on chitinous substrates

International audienceProduction of chitin deacetylases from the phytopathogenic fungus Colletotrichum gloeosporioides was successfully achieved by submerged fermentation. The highest specific activity of 0.018 U mg(-1) of protein was obtained after 96 h of cultivation at pH 6 and 28 degrees C. Two bands with molecular weights of 35 kDa and 170 kDa determined with SDS-PAGE displayed deacetylase activities as detected in the zymograms. Reacetylated commercial chitosan (52% acetylation degree) was used as substrate for the extracellular crude extract in order to estimate the kinetic parameters of acetate production as undirected deacetylation measurement. The highest acetate production of 12.8 mu mol mL(-1) was obtained using 7.5 mg mL(-1) of substrate. The produced enzyme from C. gloeosporioides achieved up to 25% deacetylation of a chitin substrate (hydrolyzed biological chitin) having 80% degree of acetylation, M-W of 102 x 10(3) g mol(-1) and a crystallinity index of ca. 60%

Thermal Treatment of Commercial Sweetener Solutions Modulates the Metabolic Responses in C57BL/6 Mice during a 24-Week-Long Exposition

The purpose of this paper was to evaluate the effect of thermal treatment (TT: 121 ± 2 °C, 15 min) on the composition of commercial sweeteners diluted in water (10 °Brix). Additionally, we evaluated the impact of this TT on metabolic responses in C57BL/6 mice during a 24-week treatment. The sweeteners included in this study were sucrose (SC), glucose-63 (GLU63), agave syrup (AS), sucralose (SUC), and steviol glycosides (STG). HPLC analysis showed changes in the concentration of simple sugars of GLU63 and AS after TT. Importantly, in all sweeteners, TT modulated metabolic responses in mice. The mice drinking thermally treated sweetener solution showed an increase of 10–13% (p < 0.05) in food intake (AS, SUC, and STG), beverage intake (2–21%; SC and GLU63), weight gain (38%; SUC), energy (10–13%; AS, SUC, and STG), glucose levels (11–17%; SC and STG), GLP-1 (30%; SC) and insulin (88%; AS) release, and the generation of protein carbonyl (SC) and malondialdehyde (all sweeteners tested) compared to mice drinking solution without TT. In conclusion, TT of sweetener solutions accentuates the metabolic responses of healthy mice, which can be related to overweight and its comorbidities

Structural Characterization of Chitin and Chitosan Obtained by Biological and Chemical Methods

International audienceChitin production was biologically achieved by lactic acid fermentation (LAP) of shrimp waste (Litopenaeus vannameii) in a packed bed column reactor with maximal percentages of demineralization (D(MIN)) and deproteinization (D(PROT)) after 96 h of 92 and 94%, respectively. This procedure also afforded high free astaxanthin recovery with up to 2400 mu g per gram of silage. Chitin product was also obtained from the shrimp waste by a chemical method using acid and alkali for comparison. The biologically obtained chitin (BIO-C) showed higher M(w) (1200 kDa) and crystallinity index (I(CR)) (86%) than the chemically extracted chitin (CH-C). A multistep freeze-pump-thaw (FPT) methodology was applied to obtain medium M(w) chitosan (400 kDa) with degree of acetylation (DA) ca. 10% from BIO-C, which was higher than that from CH-C. Additionally, I(CR) values showed the preservation of crystalline chitin structure in BIO-C derivatives at low DA (40-25%). Moreover, the FPT deacetylation of the attained BIO-C produced chitosans with bloc copolymer structure inherited from a coarse chitin crystalline morphology. Therefore, our LAP method combined with FPT proved to be an affective biological method to avoid excessive depolymerization and loss of crystallinity during chitosan production, which offers new perspective applications for this material

Prospective of the socioeconomic sector of beekeeping production in the Yucatán Peninsula, Mexico

Contexto. La actividad apícola es una alternativa de ingresos para familias en zonas rurales del mundo, mejorando significativamente su vida cotidiana. La aplicación de buenas practicas para el desarrollo de esta actividad, contribuyen positivamente a la conservación del medio ambiente, por la dinámica misma de la polinización, garantizando una producción mayor, si se protege el ciclo natural de este proceso a través de las abejas. Los gobiernos locales deben gestionar leyes y políticas que promuevan la apicultura para contribuir al bienestar social. Este estudio se enfocó en la Península de Yucatán, como sujeto de estudio, pero las metodologías de análisis y los resultados pueden ser replicables para todos los apicultores del país. Problema. Los bajos ingresos que perciben los apicultores en zonas rurales de la Península de Yucatán como fuente principal económica para sus hogares. Ausencia de tecnología innovadora y conocimiento de vanguardia, deficientes prácticas apícolas, precios no justos. Objetivo. El objetivo de este trabajo de investigación fue prospectar escenarios para identificar problemáticas socioeconómicas en el sector apícola en la Península de Yucatán - México y visibilizar las realidades presentes, factores negativos, visión y sus ecosistemas alternativos para establecer una línea base de soluciones posibles. Metodología. Se construyeron indicadores de ingresos y distribución poblacional en el sector apícola basados en la&nbsp; información emitida por entidades de gobierno con acceso abierto, para medir la pobreza. Igualmente, se construyó un estudio de prospección con el acompañamiento de los productores y actores clave sobre la base de un análisis en una matriz de impactos cruzados Multiplicación Aplicada para una Clasificación (MICMAC). Hallazgos Teóricos y Prácticos. Se identificó que los factores que han afectado las producciones (floraciones) y externalidades negativas en el sector son las afectaciones por el cambio climático, el abuso de agroquímicos, el abandono de unidades, la falta de involucramiento de los jóvenes, la falta de apoyos gubernamentales para incrementar la productividad y facilitar la movilidad y comercialización con precios más justos, entre otros, coincidiendo con lo manifestado en la literatura especializada y de acceso abierto donde se abordan diferentes problemáticas que involucran los temas agrarios. En cuanto los hallazgos prácticos, las variables claves identificadas fueron el tipo de producción, los ingresos, la sanidad, la tecnología e innovación y el impacto ambiental. Por su parte las variables determinantes fueron las alianzas y cooperación, así como las políticas públicas. Originalidad desde el punto de vista transdisciplinar y de innovación sostenible. Este estudio se desarrolló con la participación activa de apicultores de la Península de Yucatán, se procesó a través de una metodología prospectiva para graficar el mejor escenario a futuro al priorizar su visión, atender sus problemáticas, robustecer sus saberes y experiencias, identificar los actores primordiales, procesos clave para la elaboración de estrategias que contribuyan a fortalecer esta actividad, materializado en ingresos más justos para tener una vida digna. Conclusiones y limitaciones. Al respecto se concluye que la línea base de soluciones posibles deben ser enfocadas en las variables clave identificadas, bajo una perspectiva multifactorial y multidisciplinaria. Estos estudios están limitados si no se trabaja de la mano con el sector público al impulsar políticas públicas apícolas, créditos, además se requiere la intervención de la academia e institutos de ciencia y, sobre todo el involucramiento de los consumidores.Context. Beekeeping is an alternative income for families in rural areas of the world, significantly improving their daily lives. The application of good practices for the development of this activity contributes positively to the conservation of the environment, due to the very dynamics of pollination, guaranteeing greater production, if the natural cycle of this process through bees is protected. Local governments must manage laws and policies that promote beekeeping to contribute to social well-being. This study focused on the Yucatan Peninsula as the subject of the study, but the analysis methodologies and results can be replicable for all beekeepers in the country. Problem. The low income that beekeepers receive in rural areas of the Yucatan Peninsula is the main economic source for their homes. There is an absence of innovative technology and cutting-edge knowledge, poor beekeeping practices, and unfair prices. Purpose. The objective of this research work was to prospect scenarios to identify socioeconomic problems in the beekeeping sector in the Yucatan Peninsula - Mexico and to make visible the present realities, negative factors, vision and their alternative ecosystems to establish a baseline of possible solutions. &nbsp; Methodology. Income and population distribution indicators were constructed in the beekeeping sector based on information issued by government entities with open access, to measure poverty. Likewise, a prospecting study was built with the support of producers and key actors based on an analysis of a cross-impact matrix Applied Multiplication for Classification (MICMAC). Theoretical and Practical Findings. It was identified that the factors that have affected production (flowerings) and negative externalities in the sector are the effects of climate change, the abuse of agrochemicals, the abandonment of units, the lack of involvement of young people, the lack of government support to increase productivity and facilitate mobility and marketing with fairer prices, among others, coinciding with what is stated in specialized and open access literature where different problems involving agricultural issues are addressed. Regarding practical findings, the key variables identified were the type of production, income, health, technology and innovation, and environmental impact. For their part, the determining variables were alliances and cooperation, as well as public policies. Originality from a transdisciplinary and sustainable innovation point of view. This study was developed with the active participation of beekeepers from the Yucatan Peninsula, it was processed through a prospective methodology to graph the best future scenario by prioritizing their vision, addressing their problems, strengthening their knowledge and experiences, identifying the primary actors. , key processes for the development of strategies that contribute to strengthening this activity, materialized in fairer income to have a dignified life. Conclusions and limitations. In this regard, it is concluded that the baseline of possible solutions must be focused on the key variables identified, from a multifactorial and multidisciplinary perspective. These studies are limited if we do not work hand in hand with the public sector when promoting public beekeeping policies, credits, and the intervention of academia and science institutes is required, and above all, the involvement of consumers

Ultrasound Assisted Extraction for the Recovery of Phenolic Compounds from Vegetable Sources

Vegetable sources and agro-industrial residues represent an important source of phenolic compounds that are useful in a wide range of applications, especially those with biological activities. Conventional techniques of phytochemical extraction have been associated with a high consumption of organic solvents that limits the application of bioactive extracts, leading to the implementation of novel extraction technologies using mechanisms such as Ultrasound Assisted Extraction (UAE). In the present review, an analysis of the involved variables in the extraction yield of phenolic compounds through UAE is presented, highlighting the advantages of this technology based on the results obtained in various optimized studies. A comparison with other technologies and a proposal of its possible application for agro industrial residues as raw material of phenolic compounds is also indicated. Finally, it is concluded that UAE is a technology that is placed within the area of Sustainable Chemistry since it promotes the use of renewable raw materials through the extraction of phenolic compounds, implementing the substitution of organic solvents with solvents that do not present toxic effects, lowering the energy consumption when compared to conventional methods and minimizing process times and temperatures, which is useful for the extraction of thermo-labile compounds

Levan Production by <i>Suhomyces kilbournensis</i> Using Sugarcane Molasses as a Carbon Source in Submerged Fermentation

The valorization of byproducts from the sugarcane industry represents a potential alternative method with a low energy cost for the production of metabolites that are of commercial and industrial interest. The production of exopolysaccharides (EPSs) was carried out using the yeast Suhomyces kilbournensis isolated from agro-industrial sugarcane, and the products and byproducts of this agro-industrial sugarcane were used as carbon sources for their recovery. The effect of pH, temperature, and carbon and nitrogen sources and their concentration in EPS production by submerged fermentation (SmF) was studied in 170 mL glass containers of uniform geometry at 30 °C with an initial pH of 6.5. The resulting EPSs were characterized with Fourier-transform infrared spectroscopy (FT-IR). The results showed that the highest EPS production yields were 4.26 and 44.33 g/L after 6 h of fermentation using sucrose and molasses as carbon sources, respectively. Finally, an FT-IR analysis of the EPSs produced by S. kilbournensis corresponded to levan, corroborating its origin. It is important to mention that this is the first work that reports the production of levan using this yeast. This is relevant because, currently, most studies are focused on the use of recombinant and genetically modified microorganisms; in this scenario, Suhomyces kilbournensis is a native yeast isolated from the sugar production process, giving it a great advantage in the incorporation of carbon sources into their metabolic processes in order to produce levan sucrose, which uses fructose to polymerize levan