999 resultados para Berwick, Maréchal de


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aspergillus terricola and Aspergillus ochraceus, isolated from Brazilian soil, were cultivated in Vogel and Adams media supplemented with 20 different carbon sources, at 30 A 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 A degrees C and pH 6.5 for A. terricola, and 65 A degrees C and pH 5.0 for A. ochraceus. A. terricola xylanase was stable for 1 h at 60 A 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.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Référence bibliographique : Rol, 54728

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Référence bibliographique : Rol, 54723

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Référence bibliographique : Rol, 54722

Relevância:

20.00% 20.00%

Publicador: