Production and properties of xylanases from Aspergillus terricola Marchal and Aspergillus ochraceus and their use in cellulose pulp bleaching
| Autor: | Maria de Lourdes Teixeira de Moraes Polizeli, Simone de Carvalho Peixoto-Nogueira, T. M. da Silva, Michele Michelin, Jorge Henrique Almeida Betini, H. F. Terenzi, J. A. Jorge |
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| Rok vydání: | 2009 |
| Předmět: |
Aspergillus ochraceus
Aspergillus Endo-1 4-beta Xylanases biology Bran Bioengineering General Medicine Fungi imperfecti biology.organism_classification Xylan Wood Enzyme assay Enzyme Activation chemistry.chemical_compound chemistry Species Specificity Botany Enzyme Stability Xylanase biology.protein Food science Cellulose Biotechnology |
| Zdroj: | Bioprocess and biosystems engineering. 33(7) |
| ISSN: | 1615-7605 |
| Popis: | Aspergillus terricola and Aspergillus ochraceus, isolated from Brazilian soil, were cultivated in Vogel and Adams media supplemented with 20 different carbon sources, at 30 degrees C, under static conditions, for 120 and 144 h, respectively. High levels of cellulase-free xylanase were produced in birchwood or oat spelt xylan-media. Wheat bran was the most favorable agricultural residue for xylanase production. Maximum activity was obtained at 60 degrees C and pH 6.5 for A. terricola, and 65 degrees C and pH 5.0 for A. ochraceus. A. terricola xylanase was stable for 1 h at 60 degrees C and retained 50% activity after 80 min, while A. ochraceus xylanase presented a t(50) of 10 min. The xylanases were stable in an alkali pH range. Biobleaching of 10 U/g dry cellulose pulp resulted in 14.3% delignification (A. terricola) and 36.4% (A. ochraceus). The brightness was 2.4-3.4% ISO higher than the control. Analysis in SEM showed defibrillation of the microfibrils. Arabinase traces and beta-xylosidase were detected which might act synergistically with xylanase. |
| Databáze: | OpenAIRE |
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