Xylanase and beta-xylosidase from Penicillium janczewskii: Purification, characterization and hydrolysis of substrates
Electron. j. biotechnol
; 19(5): 54-62, Sept. 2016. ilus
Article
em En
| LILACS
| ID: lil-797335
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ABSTRACT
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.Palavras-chave
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Índice:
LILACS
Assunto principal:
Penicillium
/
Xilosidases
Idioma:
En
Revista:
Electron. j. biotechnol
Assunto da revista:
BIOTECNOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article