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Xylan removal by xylanase for the production of dissolving pulp from bamboo

University of British Columbia

With α-cellulose content and fiber characteristics similar to those of wood, bamboo is an attractive alternative feedstock for the production of dissolving grade pulp. A high level of hemicellulose in bamboo will lead to substantial complications in downstream processing of dissolving pulps into cellulose derivatives such as viscose, acetates, ethers etc. Xylanase treatment is an environment-friendly method that enables the selective removal of xylan (the major hemicellulose in bamboo) without detrimental effects on cellulose. In this study, we investigated a combination of mechanical refining with xylanase treatment for incorporation into a pre-hydrolysis kraft-based bamboo dissolving pulp production process. Laboratory PFI refining and xylanase treatment were combined to improve the xylan removal efficiency. Refining at 9000 revolutions increased the efficiency of subsequent enzymatic treatment resulting in a 44% removal of beta- plus gamma-cellulose with only 3 h of xylanase treatment. The alpha-cellulose content of bleached pulp prepared following combined refining-xylanase treatments was 93.37% (w/w) while the xylan content was only 2.38%. The properties of refined fibers prior to xylanase treatment, such as freeness, water retention value, fiber size and Scanning Electron Microscopy (SEM) images were investigated to further understand the underlying mechanism of the effect of refining on enzymatic treatment. The brightness, reactivity and viscosity of bleached bamboo dissolving pulp after ECF bleaching (D-EP-D) sequence were also evaluated. These results demonstrated the feasibility of combining refining and xylanase treatment to produce high quality bamboo dissolving pulp.

Text

2017-01-21

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/60269

Chemical and Biological Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/