Improving bamboo pulp delignification by grapheme-oxide-immobilised laccase-mediator system.

A laccase mediator system (LMS), i.e. Lac/ABTS, was used for bamboo pulp delignification. Both laccase and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) were then immobilised on graphene oxide (GO) to obtain GO-immobilised LMS, i.e. Lac/ABTS/GO. Lac/ABTS was also comparatively studied. The delignification selectivity and pulp properties achieved were better with Lac/ABTS/GO than Lac/ABTS in the catalytic delignification of bamboo pulp. The scanning electron micrograph of Lac/ABTS/GO-treated pulp showed a positive change in morphology and integrity of the pulp. UV resonance Raman spectroscopy also confirmed the better catalytic selectivity of Lac/ABTS/GO. Further, gel permeation chromatography, 31phosphorus nuclear magnetic resonance spectra and Fouriertransform infrared spectra of residual lignin samples from the treated pulp indicated an increase in the degradation and oxidation of lignin by Lac/ABTS/GO. [ABSTRACT FROM AUTHOR]