Ultrasound Assisted Alkaline Pre‐treatment Efficiently Solubilises Hemicellulose from Oat Hulls

Schmitz, Eva; Karlsson, Eva Nordberg; Adlercreutz, Patrick

doi:10.1007/s12649-021-01406-0

Cited by 16 publications

(2 citation statements)

References 19 publications

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“…Finally, the fibers recovered by centrifugation at 3893 × g for 5 min to remove the ethanol, washed with water and the extracted fibers were freeze dried. AX content of the oat fibers were determined through acid hydrolysis and quantification of arabinose and xylose through HPAEC–PAD as previously described ( Schmitz et al. 2021 ).…”

Section: Methodsmentioning

confidence: 99%

Novel thermostable GH5_34 arabinoxylanase with an atypical CBM6, displays activity on oat fibre xylan for prebiotic production

et al. 2022

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Carbohydrate active enzymes are valuable tools in cereal processing to valorise underutilized side streams. By solubilizing hemicellulose and modifying the fibre structure, novel food products with increased nutritional value can be created. In this study, a novel GH5_34 subfamily arabinoxylanase from Herbinix hemicellulosilytica, HhXyn5A, was identified, produced and extensively characterized, for the intended exploitation in cereal processing to solubilize potential prebiotic fibres; arabinoxylo-oligosaccharides (AXOS). The purified two-domain HhXyn5A (catalytic domain and CBM6) demonstrated high storage stability, showed a melting temperature Tm of 61 °C and optimum reaction conditions were determined to 55 °C and pH 6.5 on wheat arabinoxylan (WAX). HhXyn5A demonstrated activity on various commercial cereal arabinoxylans and produced prebiotic AXOS, while the sole catalytic domain of HhXyn5A did not demonstrate detectable activity. HhXyn5A demonstrated no side activity on oat β-glucan. In contrast to the commercially available homologue CtXyn5A, HhXyn5A gave a more specific HPAEC–PAD oligosaccharide product profile when using WAX and alkali extracted oat bran fibres as substrate. Results from multiple sequence alignment of GH5_34 enzymes, homology modelling of HhXyn5A and docking simulations with ligands XXXA3, XXXA3XX, and X5, concluded that the active site of HhXyl5A catalytic domain is highly conserved and can accommodate both shorter and longer AXOS ligands. However, significant structural dissimilarities between HhXyn5A and CtXyn5A in the binding cleft of CBM6, due to lack of important ligand interacting residues, is suggested to cause the observed differences in substrate specificity and product formation.

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Section: Methodsmentioning

confidence: 99%

Novel thermostable GH5_34 arabinoxylanase with an atypical CBM6, displays activity on oat fibre xylan for prebiotic production

et al. 2022

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“…On the other hand, the alkaline treatment reduced their crude fiber content (Table 1), which could be attributed to the break of ester and ether bonds between some fibers, such as hemicellulose and lignin. This increases their solubility and, consequently, reduces the fiber content of lignocellulosic residues [64,65].…”

Section: Composition Of Raw Materialsmentioning

confidence: 99%

Produção de cogumelos de Pleurotus ostreatus enriquecidos com selênio e alimentação de suínos para estudos de biodisponibilidade do mineral

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Esta dissertação está inserida no contexto atual das discussões do ramo das políticas públicas sobre a descentralização das ações do Estado e na execução de atividades considerados de cunho social pelas organizações da sociedade civil. O objetivo geral deste estudo visou caracterizar a accountability realizada pelas OSC nas parcerias estabelecidas com diferentes agentes financiadores. O referencial teórico propõe-se a versar-se sobre o conceito de accountability e a mostrar que o seu conceito não é de fácil compreensão e que é necessário um modelo de análise para compreender as questões que envolvem sua totalidade. Com intuito de avançar no debate, ainda no referencial teórico, apresenta como as OSCs se inserem no contexto das políticas públicas, representando um seguimento de atividades sem fins lucrativos e que recebem uma diversidade de recursos para a realização de suas atividades sociais. Em termos metodológicos, a pesquisa é qualitativa e possuiu duas etapas. Na primeira etapa foi realizada uma coleta de dados de cunho documental onde os dados encontrados nos documentos foram tratados por análise de conteúdo. Para a segunda etapa foram realizadas entrevistas com pessoas da OSC1 e do CMDCA do município de Viçosa. Para análise das entrevistas foi utilizada a análise de conteúdo com auxílio do software IRAMUTEQ. Os resultados encontrados permitiram demonstrar que a accountability vai além da simples generalização de seu conteúdo com as questões voltadas apenas para a prestação de contas, a ideia final é a busca pela eficiência, efetividade, na aplicação dos recursos sejam eles públicos ou privados, desde que busquem gerar valor para a sociedade e ao mesmo tempo demonstrar de forma clara e objetiva, não apenas para os agentes financiadores, mas também para a sociedade os serviços providos a partir da utilização desses recursos. Foi possível constatar, também que o ambiente normativo da OSC1 propicia condições para o desenvolvimento da accountability em ambiente institucional o que facilita que aconteça a responsabilização constantes da OSC1 perante a parceria por elas estabelecidas por diferentes agentes financiadores. Palavras-chave: Accountability. Organizações. Governo

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Novel Function of CtXyn5A from Acetivibrio thermocellus: Dual Arabinoxylanase and Feruloyl Esterase Activity in the Same Active Site**

et al. 2022

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Enzymes' uncharacterised side activities can have significant effects on reaction products and yields. Hence, their identification and characterisation are crucial for the development of successful reaction systems. Here, we report the presence of feruloyl esterase activity in CtXyn5A from Acetivibrio thermocellus, besides its well-known arabinoxylanase activity, for the first time. Activity analysis of enzyme variants mutated in the catalytic nucleophile, Glu279, confirmed removal of all activity for E279A and E279L, and increased esterase activity while removing xylanase activity for E279S, thus allowing the proposal that both reaction types are catalysed in the same active site in two subsequential steps. The ferulic acid substituent is cleaved off first, followed by hydrolysis of the xylan backbone. The esterase activity on complex carbohydrates was found to be higher than that of a designated ferulic acid esterase (E-FAERU). Therefore, we conclude that the enzyme exhibits a dual function rather than an esterase side activity.

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Ultrasound Assisted Alkaline Pre‐treatment Efficiently Solubilises Hemicellulose from Oat Hulls

Cited by 16 publications

References 19 publications

Novel thermostable GH5_34 arabinoxylanase with an atypical CBM6, displays activity on oat fibre xylan for prebiotic production

Novel thermostable GH5_34 arabinoxylanase with an atypical CBM6, displays activity on oat fibre xylan for prebiotic production

Produção de cogumelos de Pleurotus ostreatus enriquecidos com selênio e alimentação de suínos para estudos de biodisponibilidade do mineral

Novel Function of CtXyn5A from Acetivibrio thermocellus: Dual Arabinoxylanase and Feruloyl Esterase Activity in the Same Active Site**

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