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Provedor de dados:  Electron. J. Biotechnol.
País:  Chile
Título:  Xylanase and β-xylosidase from Penicillium janczewskii: Purification, characterization and hydrolysis of substrates
Autores:  Fanchini Terrasan,César Rafael
Guisan,José Manuel
Cano Carmona,Eleonora
Data:  2016-09-01
Ano:  2016
Palavras-chave:  Xylanolytic enzymes
Enzyme characterization
Enzyme purification
Xylan hydrolysis
Xylooligosaccharides hydrolysis
Resumo:  Background: Xylanases and β-D-xylosidases are the most important enzymes responsible for the degradation of xylan, the second main constituent of plant cell walls. Results: In this study, the main extracellular xylanase (XYL I) and p-xylosidase (BXYL I) from the fungus Penicillium janczewskii were purified, characterized and applied for the hydrolysis of different substrates. Their molecular weights under denaturing and non-denaturing conditions were, respectively, 30.4 and 23.6 kDa for XYL I, and 100 and 200 kDa for BXYL I, indicating that the latter is homodimeric. XYL I is highly glycosylated (78%) with optimal activity in pH 6.0 at 65°C, while BXYL I presented lower sugar content (10.5%) and optimal activity in pH 5.0 at 75°C. The half-lives of XYL I at 55, 60 and 65°C were 125,16 and 6 min, respectively. At 60°C, BXYL I retained almost 100% of the activity after 6 h. NH4+,Na+, DTT and β-mercaptoethanol stimulated XYL I, while activation of BXYL I was not observed. Interestingly, XYL I was only partially inhibited by Hg2+, while BXYL I was completely inhibited. Xylobiose, xylotriose and larger xylooligosaccharides were the main products from xylan hydrolysis by XYL I. BXYL I hydrolyzed xylobiose and larger xylooligosaccharides with no activity against xylans. Conclusion: The enzymes act synergistically in the degradation of xylans, and present industrial characteristics especially in relation to optimal activity at high temperatures, prolonged stability of BXYL I at 60°C, and stability of XYL I in wide pH range.
Tipo:  Journal article
Idioma:  Inglês
Editor:  Pontificia Universidad Católica de Valparaíso
Formato:  text/html
Fonte:  Electronic Journal of Biotechnology v.19 n.5 2016

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