Synthesis, characterization and enzymatic surface roughing of cellulose/xylan composite films

Synopsis: Xylanase treatment is an environmentally friendly approach to selectively modify the surface of cellulose/xylan composite film without compromising its structural advantages. [Display omitted] •Transparent cellulose/xylan composite films was facilely fabricated.•Xylanase treatment could selectively hydrolyze xylan component to etch/rough its surface.•Limited interaction between cellulose and xylan was formed.•Xylan component in the surface of composite films was highly accessible for hydrolysis. Upgrading renewable cellulose biopolymer to various high-value material/chemical is of great importance in building a sustainable bio-economy. This work assessed the technical feasibility of fabricating transparent cellulose/xylan composite films using facile solution-casting method. More importantly, this work also initially assessed the technical potential of xylanase treatment to selectively modify the surface of the obtained composite films with the goal of extending their applications. When bleached Kraft xylan addition was lower than 20 wt%, the composite films could still retain their original mechanical and structural advantages. Xylanase treatment specifically removed 26.0% and 32.3% xylan of the composite films with an enzyme loading of 2 and 5 mg g−1 cellulose, respectively. It was shown that xylan component was heterogeneously located in the surface of the composite films during film-casting process, which allowed the subsequent surface etching/roughing at nanoscale using facile xylanase treatment without compromising their structural advantages.