Enzymatic and chemical production of xylooligosaccharides from sugarcane bagasse and leaf
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2020-02-19
Autores
Forsan, Carolina Froes
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Universidade Estadual Paulista (Unesp)
Resumo
A partir da biomassa podem ser obtidos produtos de alto valor, entre eles, os xilooligossacarídeos (XOS). Eles agem como prebióticos, componentes alimentares que não são digeridos e estimulam o crescimento de microrganismos benéficos presentes no intestino, como as bifidobactérias e os lactobacilos, melhorando a saúde do hospedeiro. XOS tem uma variedade de aplicações na indústria alimentícia e farmacêutica. O objetivo deste estudo foi comparar a eficácia dos métodos de hidrólise com ácido diluído e auto-hidrólise com hidrólise enzimática, utilizando bagaço e folha de cana-de-açúcar para produção de XOS. O bagaço e a folha foram hidrolisados com ácido sulfúrico ou acético e os parâmetros foram definidos através de um planejamento composto central 23, utilizando ácido sulfúrico ou acético em concentrações entre 1 % e 3 % (m/v); temperatura de 100 °C a 160 °C e tempo de reação de 15 a 55 min. Na auto-hidrólise, um planejamento composto central 22 foi realizado com temperaturas variando de 100 °C a 160 °C e tempo de reação de 15 a 55 min. XOS também foram produzidos a partir da xilana extraída do bagaço e da folha de cana-de-açúcar. A extração alcalina da xilana foi realizada com peróxido de hidrogênio 6 % (m/v), por 4 horas a 25 ºC. A xilana foi utilizada na hidrólise com ácido acético e sulfúrico diluído e na hidrólise enzimática. Os parâmetros da hidrólise ácida foram definidos através de um planejamento composto central 22 com concentração ácida de 1,5 % a 4 % (m/v), tempo de reação de 10 a 30 min e temperatura de 130 °C. A hidrólise enzimática foi realizada com endo-β-1,4-xilanase de Aspergillus versicolor e planejamento composto central 22 com atividade enzimática de 30 a 100 UI.g-1, concentração de substrato (xilana) de 1 % a 5 % por 24 h. Na hidrólise do bagaço e da folha com ácido sulfúrico diluído, a conversão da xilana em XOS foi de 90,13 % e 62,18 % em condições semelhantes (79,55 ºC, 35 min e ácido 2 % m/v). A hidrólise do bagaço e da folha com ácido acético resultou em rendimento de 18,41 % (100 ºC, 15 min e ácido 1% (m/v) e 22,78 % (180,45 ºC, 35 min e ácido 2 % m/v). Na auto-hidrólise, os valores obtidos para bagaço e folha foram 13,67 % (35 min e 172,43 ºC) e 20,71 % (35 min, 130 ºC). Na hidrólise da xilana extraída do bagaço e folha com ácido sulfúrico, os valores foram de 40,16 % e 45,37 % em condições similares (concentração de ácido de 1,5 %, 10 min a 130 ºC). Na hidrólise da xilana extraída do bagaço e da folha com ácido acético, os valores foram 56,29 % (concentração de ácido de 1,5 %, 30 min a 130 ºC) e 53,65 % (concentração de ácido de 2,75 %, 34,14 min a 130 ºC). Na hidrólise enzimática da xilana extraída do bagaço e da folha, os valores foram de 67,43 % e 69,71 % em condições semelhantes (carga enzimática de 65 UI.g-1 e concentração de substrato de 0,17 %). Os maiores resultados da conversão de xilana em XOS foram obtidos na hidrólise do bagaço e folha de cana-de-açúcar com ácido sulfúrico e na hidrólise enzimática e com ácido acético e sulfúrico da xilana do bagaço e da folha de cana-de-açúcar. Exceto pela hidrólise enzimática, houve produção de xilose. O menor rendimento foi obtido na auto-hidrólise devido a condições mais amenas. A xilose é indesejável no processo, pois dificulta a purificação do XOS. Com base nos resultados, a hidrólise enzimática e ácida mostrou-se promissora na produção de XOS em larga escala.
From biomass, high-value products can be obtained, including xylooligosaccharides (XOS). They act as prebiotics, undigested food components that stimulate the growth of beneficial microorganisms present in the intestine, such as bifidobacteria and lactobacilli, improving host health. XOS have a range of applications in the food and pharmaceutical industry. The aim of this study was to compare the effectiveness of dilute acid hydrolysis, enzymatic hydrolysis and autohydrolysis methods using sugarcane bagasse and leaf to XOS production. Sugarcane bagasse and leaf were hydrolysate with sulfuric or acetic acid and parameters were defined through a central composite design 23 using sulfuric or acetic acid at concentrations between 1 % and 3 % (m/v); temperature from 100 °C to 160 °C and reaction time from 15 to 55 min. In autohydrolysis a central composite design 22 was performed using temperatures ranging from 100 °C to 160 °C with a reaction time of 15 to 55 min. XOS were also produced from xylan extracted from sugarcane bagasse and leaf. Alkaline extraction of xylan was performed with 6 % (m/v) hydrogen peroxide, for 4 h at 25 ºC. Xylan was used in hydrolysis with dilute acetic and sulfuric acid and in enzymatic hydrolysis. The parameters of the acid hydrolysis were defined through a central composite design 22 with acid concentration from 1.5 % to 4 % (m/v), reaction time from 10 to 30 min, and temperature of 130 °C. Enzymatic hydrolysis was performed using endo-β-1.4-xylanase from Aspergillus versicolor and central composite design 22 with enzyme activity from 30 to 100 UI.g-1, substrate (xylan) concentration from 1 % to 5 % for 24 h. In hydrolysis of bagasse and leaf with dilute sulfuric acid the conversion of xylan into XOS was 90.13 % and 62.18 % under similar conditions (79.55 ºC, 35 min and 2 % m/v acid). The hydrolysis of bagasse and leaf with acetic acid resulted in a yield of 18.41 % (100 ºC, 15 min and 1% m/v acid) and 22.78 % (180.45 ºC, 35 min and 2 % m/v acid). In autohydrolysis the values obtained for bagasse and leaf were 13.67 % (35 min and 172.43 ºC) and 20.71 % (35 min, 130 ºC). In hydrolysis of xylan extracted from sugarcane bagasse and leaf with sulfuric acid the values were 40.16 % and 45.37 % under similar conditions (1.5 % acid concentration, 10 min at 130 ºC). In hydrolysis of xylan extracted from sugarcane bagasse and leaf with acetic acid the values were 56.29 % (1.5 % acid concentration, 30 min at 130 ºC) and 53.65 % (2.75 % acid concentration, 34.14 min at 130 ºC). In enzymatic hydrolysis of xylan extracted from sugarcane bagasse and leaf, the values were 67.43 % and 69.71 % under similar conditions (enzymatic load of 65 UI.g-1 and substrate concentration of 0.17 %). The highest results of xylan conversion into XOS were obtained in the hydrolysis of sugarcane bagasse and leaf with sulfuric acid and in the hydrolysis of xylan from sugarcane bagasse and leaf with acetic and sulfuric acid and enzymatic hydrolysis. Except for enzymatic hydrolysis, there was xylose production. The lowest yield was obtained on autohydrolysis due to milder conditions. Xylose is undesirable in the process as it hinders the purification of XOS. Based on the results, enzymatic and acid hydrolysis has shown promise in large scale XOS production.
From biomass, high-value products can be obtained, including xylooligosaccharides (XOS). They act as prebiotics, undigested food components that stimulate the growth of beneficial microorganisms present in the intestine, such as bifidobacteria and lactobacilli, improving host health. XOS have a range of applications in the food and pharmaceutical industry. The aim of this study was to compare the effectiveness of dilute acid hydrolysis, enzymatic hydrolysis and autohydrolysis methods using sugarcane bagasse and leaf to XOS production. Sugarcane bagasse and leaf were hydrolysate with sulfuric or acetic acid and parameters were defined through a central composite design 23 using sulfuric or acetic acid at concentrations between 1 % and 3 % (m/v); temperature from 100 °C to 160 °C and reaction time from 15 to 55 min. In autohydrolysis a central composite design 22 was performed using temperatures ranging from 100 °C to 160 °C with a reaction time of 15 to 55 min. XOS were also produced from xylan extracted from sugarcane bagasse and leaf. Alkaline extraction of xylan was performed with 6 % (m/v) hydrogen peroxide, for 4 h at 25 ºC. Xylan was used in hydrolysis with dilute acetic and sulfuric acid and in enzymatic hydrolysis. The parameters of the acid hydrolysis were defined through a central composite design 22 with acid concentration from 1.5 % to 4 % (m/v), reaction time from 10 to 30 min, and temperature of 130 °C. Enzymatic hydrolysis was performed using endo-β-1.4-xylanase from Aspergillus versicolor and central composite design 22 with enzyme activity from 30 to 100 UI.g-1, substrate (xylan) concentration from 1 % to 5 % for 24 h. In hydrolysis of bagasse and leaf with dilute sulfuric acid the conversion of xylan into XOS was 90.13 % and 62.18 % under similar conditions (79.55 ºC, 35 min and 2 % m/v acid). The hydrolysis of bagasse and leaf with acetic acid resulted in a yield of 18.41 % (100 ºC, 15 min and 1% m/v acid) and 22.78 % (180.45 ºC, 35 min and 2 % m/v acid). In autohydrolysis the values obtained for bagasse and leaf were 13.67 % (35 min and 172.43 ºC) and 20.71 % (35 min, 130 ºC). In hydrolysis of xylan extracted from sugarcane bagasse and leaf with sulfuric acid the values were 40.16 % and 45.37 % under similar conditions (1.5 % acid concentration, 10 min at 130 ºC). In hydrolysis of xylan extracted from sugarcane bagasse and leaf with acetic acid the values were 56.29 % (1.5 % acid concentration, 30 min at 130 ºC) and 53.65 % (2.75 % acid concentration, 34.14 min at 130 ºC). In enzymatic hydrolysis of xylan extracted from sugarcane bagasse and leaf, the values were 67.43 % and 69.71 % under similar conditions (enzymatic load of 65 UI.g-1 and substrate concentration of 0.17 %). The highest results of xylan conversion into XOS were obtained in the hydrolysis of sugarcane bagasse and leaf with sulfuric acid and in the hydrolysis of xylan from sugarcane bagasse and leaf with acetic and sulfuric acid and enzymatic hydrolysis. Except for enzymatic hydrolysis, there was xylose production. The lowest yield was obtained on autohydrolysis due to milder conditions. Xylose is undesirable in the process as it hinders the purification of XOS. Based on the results, enzymatic and acid hydrolysis has shown promise in large scale XOS production.
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Palavras-chave
Hemicellulose, Xylooligosaccharides, Enzymatic hydrolysis, Acid hydrolysis, Autohydrolysis, Hemicelulose, Xilo-oligossacarídeos, Hidrólise enzimática, Hidrólise ácida, Auto-hidrólise