Estudio cinético de la hidrólisis ácida de la fracción hemicelulósica del rastrojo de piña (ananas comusus)
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2009-11
Autores
Méndez Yesca, Andrea
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Universidad Nacional (Costa Rica)
Resumen
En los últimos años se ha presentado un notable incremento en el cultivo de la piña, debido a su creciente demanda en los mercados internacionales como fruta fresca y a la gran canfidad de productos que se pueden elaborar su industrialización. Uno de los principales desechos generados después de este proceso, es el rastrojo de piña, el cual debido a su alto contenido de hemicelulosa puede ser somefdo a un proceso de hidrólisis con ácido diluido para generar xilosa. Este azúcar es utilizado en procesos biotecnológicos para la obtención de un producto de alto valor agregado, como lo es el xilitol, un edulcorante natural que posee múltiples aplicaciones en la industria alimenticia y farmacéutica.
En este trabajo se efectuó la caracterización fisica y química del rastrojo de piña demostrando que dicho material lignocelulósico está compuesto por 29,303 (±0,003) % de a-celulosa, 54,722 % de holocelulosa, 25,419 % de hemicelulosa y 14,70 % de pentosanos, lo cual indica que es un sustrato adecuado para la producción de xilosa.
La hidrólisis ácida del sustrato se efectuó a 98 0C utilizando concentraciones de H2S04 al 2, 4 y 6% v/v y tiempos de reacción variables entre los 20 a 125 minutos. Para cada tiempo de reacción y concentración de ácido utilizada, se cuantificó la xilosa obtenida mediante cromatografia líquida de alta resolución (HPLC), así como también productos secundarios de la hidrólisis, tales como el ácido acético y furfural, mediante cromatografia de gases (GC).
La mayor producción de xilosa se alcanzó a los 100 minutos de reacción utilizando H2S04 al 4% v/v y correspondió a 14,773 ± 0,008 g/L, para un porcentaje de rendimiento del 88 (±2) % del xilano presente en el rastrojo de piña; utilizando. La concentración de los productos secundarios ácido acético y furfural, fue de 3,680 ± 0,004 g/L y 1,4173 ± 0,0002 g/L respectivamente.
Con las concentraciones obtenidas, para cada uno de los componentes a lo largo del tiempo de reacción, y aplicando el modelo cinético de pseudoprimer orden propuesto por Saeman en 1945, para la producción de xilosa y modelos similares para la generación de ácido acéfco y furfural, se determinaron los parámetros cinéticos que describen la concentración de cada componente a lo largo del tiempo de reacción.
In recent years there has been a notable increase in the cultivation of pineapples, due to its growing demand in international markets as fresh fruit and the large quantity of products that can be produced through industrialization. One of the main wastes generated after this process is pineapple stubble, which due to its high hemicellulose content can be subjected to a hydrolysis process with dilute acid to generate xylose. This sugar is used in biotechnological processes to obtain a product with high added value, such as xylitol, a natural sweetener that has multiple applications in the food and pharmaceutical industry. In this work, the physical and chemical characterization of the pineapple stubble was carried out, demonstrating that said lignocellulosic material is composed of 29.303 (±0.003) % a-cellulose, 54.722 % holocellulose, 25.419 % hemicellulose and 14.70 % pentosans, which indicates that it is a suitable substrate for the production of xylose. The acid hydrolysis of the substrate was carried out at 98 0C using H2SO4 concentrations at 2, 4 and 6% v/v and variable reaction times between 20 and 125 minutes. For each reaction time and acid concentration used, the xylose obtained was quantified by high performance liquid chromatography (HPLC), as well as by-products of hydrolysis, such as acetic acid and furfural, by gas chromatography (GC). . The highest production of xylose was reached after 100 minutes of reaction using 4% v/v H2SO4 and corresponded to 14.773 ± 0.008 g/L, for a percentage yield of 88 (±2) % of xylan present in the pineapple stubble. ; using. The concentration of the secondary products acetic acid and furfural was 3.680 ± 0.004 g/L and 1.4173 ± 0.0002 g/L respectively. With the concentrations obtained, for each of the components throughout the reaction time, and applying the pseudo-first order kinetic model proposed by Saeman in 1945, for the production of xylose and similar models for the generation of acetic acid and furfural, The kinetic parameters that describe the concentration of each component throughout the reaction time were determined.
In recent years there has been a notable increase in the cultivation of pineapples, due to its growing demand in international markets as fresh fruit and the large quantity of products that can be produced through industrialization. One of the main wastes generated after this process is pineapple stubble, which due to its high hemicellulose content can be subjected to a hydrolysis process with dilute acid to generate xylose. This sugar is used in biotechnological processes to obtain a product with high added value, such as xylitol, a natural sweetener that has multiple applications in the food and pharmaceutical industry. In this work, the physical and chemical characterization of the pineapple stubble was carried out, demonstrating that said lignocellulosic material is composed of 29.303 (±0.003) % a-cellulose, 54.722 % holocellulose, 25.419 % hemicellulose and 14.70 % pentosans, which indicates that it is a suitable substrate for the production of xylose. The acid hydrolysis of the substrate was carried out at 98 0C using H2SO4 concentrations at 2, 4 and 6% v/v and variable reaction times between 20 and 125 minutes. For each reaction time and acid concentration used, the xylose obtained was quantified by high performance liquid chromatography (HPLC), as well as by-products of hydrolysis, such as acetic acid and furfural, by gas chromatography (GC). . The highest production of xylose was reached after 100 minutes of reaction using 4% v/v H2SO4 and corresponded to 14.773 ± 0.008 g/L, for a percentage yield of 88 (±2) % of xylan present in the pineapple stubble. ; using. The concentration of the secondary products acetic acid and furfural was 3.680 ± 0.004 g/L and 1.4173 ± 0.0002 g/L respectively. With the concentrations obtained, for each of the components throughout the reaction time, and applying the pseudo-first order kinetic model proposed by Saeman in 1945, for the production of xylose and similar models for the generation of acetic acid and furfural, The kinetic parameters that describe the concentration of each component throughout the reaction time were determined.
Descripción
Méndez Yesca, A. (2009). Estudio cinético de la hidrólisis ácida de la fracción hemicelulósica del rastrojo de piña (ananas comusus). [Tesis de Licenciatura]. Universidad Nacional, Heredia, Costa Rica.
Palabras clave
HIDROLISIS, HYDROLYSIS, RESIDUOS, PINEAPPLE, PIÑA, ANANAS COMOSUS, CELULOSA