Efeito prebiótico de xilo-oligossacarídeos produzidos a partir da hemicelulose de bagaço de cana-de-açúcar utilizando extração alcalina e hidrólise de xilanases fúngicas
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Data
2016-04-07
Autores
Figueiredo, Franciane Cristina de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os xilo-oligossacarídeos (XOs) e fruto-oligossacarídeos (FOs) apresentam atividades prebióticas, favorecendo a melhora nas funções intestinais, ação imunológica, antimicrobiana e outros benefícios à saúde. A produção dos XOs pode ser realizada pela utilização de materiais lignocelulósicos (MLCs). O objetivo deste trabalho foi aperfeiçoar a extração de hemicelulose a partir do bagaço de cana-de-açúcar, além de comparar a produção de XOs com xilanases de Trichoderma reesei QM 9414 e Aspergilus fumigatus M51. Foram feitos testes de digestibilidade “in vitro” e também de fermentação “in vitro” com bactérias probióticas e patogênicas para avaliar o potencial prebiótico de XOs produzidos por tratamento alcalino e compará-los com XOs e FOs comerciais. Os pré-tratamentos alcalinos desenvolvidos com 10% de KOH a 70ºC (tratamento 1) e com 5% de KOH a 121ºC (tratamento 3) se mostraram similares ao método que utiliza 24% de KOH a 35ºC (método ZD) para extração de hemicelulose, porém são mais simplificados e econômicos. O tratamento 1 apresentou redução de 54,1% de KOH e 1,98% de etanol e o tratamento 3 reduziu em 76,2% o KOH e 40,9% o etanol. Estes três experimentos de extração de hemicelulose foram selecionados para os testes de hidrólise enzimática com xilanases dos fungos T. reesei e A. fumigatus para produção de XOs. A hidrólise com enzimas de T. reesei se mostrou mais vantajosa apenas para produção de xilose (54,9%) em 24 horas, utilizando-se hemicelulose produzida pelo tratamento número 3. Testes com enzimas de A. fumigatus apresentaram melhor rendimento de XOs (27,1%) em 24 horas e menor rendimento de xilose (19,6%), com hemicelulose do tratamento 1 (XOs LABI). Experimentos de fermentação “in vitro” demonstraram a capacidade de Lactobacillus e Bifidobacterium fermentarem XOs e FOs comerciais, destacando-se a preferência de B. breve e L. brevis por XOs comercial, enquanto B. lactis e L. acidophilus demonstraram preferência por FOs comercial. B. longum cresceu tanto nos XOs e FOs comerciais e B. animalis não cresceu em nenhum oligossacarídeo comercial. Salmonella enterica em 4 horas não cresceu quando os oligossacarídeos estavam presentes, diferentes dos meios com outras fontes de carboidratos, comprovando-se a seletividade destes prebióticos por linhagens probióticas. Os XOs LABI não foram capazes de estimular o crescimento da maioria das bactérias probióticas, embora tenham inibido o crescimento de S. enterica e resistido à ação de enzimas digestivas. Estes dados indicam a provável ação prebiótica dos XOs LABI e a necessidade de purificação do produto para eliminar possíveis resíduos da extração, os quais inibem fortemente o crescimento dos micro-organismos estudados.
The xylo-oligosaccharides (XOs) and fructo-oligosaccharides (FOs) have prebiotic activities, improving bowel function, immunological and antimicrobial activity and other health benefits. XOs production can be accomplished by the use of lignocellulosic materials (LCMs). The goal of this work was to improve the hemicellulose extraction from sugarcane bagasse and to compare the XOs production using xylanases from Trichoderma reesei QM 9414 and Aspergillus fumigatus M51. We performed "in vitro" digestibility tests and also "in vitro" fermentation with probiotic and pathogenic bacteria to evaluate the prebiotic potential of XOs produced by alkali treatment and compared it with commercial XOs and FOs. Alkaline pretreatments developed with 10% KOH at 70° C (treatment 1) and 5% KOH at 121° C (treatment 3) were similar to the method using 24% KOH at 35° C (ZD method) for hemicellulose extraction, but they were more simplified and economical. Treatment 1 presented a reduction of 54.1% KOH and 1.98% ethanol and treatment 3 reduced KOH in 76.2% and ethanol in 40.9%. These three hemicellulose extraction experiments were selected for XOs production in the enzymatic hydrolysis tests with fungal xylanases of T. reesei and A. fumigatus. Hydrolysis with T. reesei enzymes proved advantageous only for xylose production (54.9%) at 24 hours, using hemicellulose produced by treatment number 3. Testing with A. fumigatus enzymes showed better XOs production (27.1%) at 24 hours and lower release of xylose (19.6%), using hemicellulose obtained by treatment 1 (XOs LABI). Fermentation experiments "in vitro" showed the ability of Lactobacillus and Bifidobacterium to ferment commercial XOs and FOs, emphasizing the preference of L. brevis and B. breve for commercial XOs while B. lactis and L. acidophilus demonstrated preference for commercial FOs. B. longum grew in both XOs and commercial FOs and B. animalis did not grow in any commercial oligosaccharide. Regarding the cultivation of Salmonella enterica, in four hours there was no growth where oligosaccharides were present, opposed to medium with other sources of carbohydrate, confirming the selectivity of this prebiotic by probiotic bacteria. XOs LABI were not able to stimulate the growth of most probiotic bacteria, although they inhibited the growth of S. enterica and resisted the digestives enzymes. These results indicate the probable prebiotic action of XOs LABI and the need of purification to eliminate possible residues from the extraction, which strongly inhibit the growth of the microorganisms studied.
The xylo-oligosaccharides (XOs) and fructo-oligosaccharides (FOs) have prebiotic activities, improving bowel function, immunological and antimicrobial activity and other health benefits. XOs production can be accomplished by the use of lignocellulosic materials (LCMs). The goal of this work was to improve the hemicellulose extraction from sugarcane bagasse and to compare the XOs production using xylanases from Trichoderma reesei QM 9414 and Aspergillus fumigatus M51. We performed "in vitro" digestibility tests and also "in vitro" fermentation with probiotic and pathogenic bacteria to evaluate the prebiotic potential of XOs produced by alkali treatment and compared it with commercial XOs and FOs. Alkaline pretreatments developed with 10% KOH at 70° C (treatment 1) and 5% KOH at 121° C (treatment 3) were similar to the method using 24% KOH at 35° C (ZD method) for hemicellulose extraction, but they were more simplified and economical. Treatment 1 presented a reduction of 54.1% KOH and 1.98% ethanol and treatment 3 reduced KOH in 76.2% and ethanol in 40.9%. These three hemicellulose extraction experiments were selected for XOs production in the enzymatic hydrolysis tests with fungal xylanases of T. reesei and A. fumigatus. Hydrolysis with T. reesei enzymes proved advantageous only for xylose production (54.9%) at 24 hours, using hemicellulose produced by treatment number 3. Testing with A. fumigatus enzymes showed better XOs production (27.1%) at 24 hours and lower release of xylose (19.6%), using hemicellulose obtained by treatment 1 (XOs LABI). Fermentation experiments "in vitro" showed the ability of Lactobacillus and Bifidobacterium to ferment commercial XOs and FOs, emphasizing the preference of L. brevis and B. breve for commercial XOs while B. lactis and L. acidophilus demonstrated preference for commercial FOs. B. longum grew in both XOs and commercial FOs and B. animalis did not grow in any commercial oligosaccharide. Regarding the cultivation of Salmonella enterica, in four hours there was no growth where oligosaccharides were present, opposed to medium with other sources of carbohydrate, confirming the selectivity of this prebiotic by probiotic bacteria. XOs LABI were not able to stimulate the growth of most probiotic bacteria, although they inhibited the growth of S. enterica and resisted the digestives enzymes. These results indicate the probable prebiotic action of XOs LABI and the need of purification to eliminate possible residues from the extraction, which strongly inhibit the growth of the microorganisms studied.
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Palavras-chave
Xilo-oligossacarídeo, Pré-tratamento alcalino, Hidrólise enzimática, Bagaço de cana-de-açúcar, Xylo-oligosaccharide, Enzymatic hydrolysis, Sugarcane bagasse