English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The production of xylanase without cellulase is required for prebleaching of pulp in pulp and paper industry. Aspergillus flavus produced high levels of xylanase on agricultural residues with wheat bran and sugarcane bagasse (4.17 U/mg), and wheat bran and corncob (2.97 U/mg). Xylanase was found to be stable at 45°C with 100% of its original activity remaining after 2 h incubation. At 50°C, xylanase was stable for the first twenty minutes, and had half-life of 50 min. The pH stability for the xylanase from A. flavus was most stable in the range of pH 3.0-8.0 retaining more that 100% activity after 1 h. The addition of 5% glycerol, mannitol or xylitol protected the xylanase from thermal inactivation at 50°C. The protective effect by glycerol, xylitol and mannitol resulted in increases of 162, 262.5 and 150% when compared with the control at 120 min, approximately. Increasing the polyols concentration up to 20% (w/v) further improved the thermostability of xylanase after 120 min at 50°C by 300% when compared with the control (no additive). The kappa number reduced 2.56 points, which corresponds to 18.34 kappa efficiency. This xylanase is an attractive enzyme for potential future application in the pulp and paper industries, since industrial application requires a cellulase-free activity, maintenance of high temperature and enzyme stability are desirable.   Key words: Aspergillus flavus, polyols, xylanase, biobleaching cellulose pulp.

african journal of biotechnology

Production of cellulase-free xylanase by Aspergillus flavus: Effect of polyols on the thermostability and its application on cellulose pulp biobleaching