Recycling immobilized laccase for lignin removal from prehydrolysis liquor of kraft-based dissolving pulp

Abstract

Laccase treatment of prehydrolysis liquor (PHL) produced in a kraft-based dissolving pulp production may allow for purification of its hemicelluloses. In this work, a magnetic support of magnetic silica particle (Fe3O4/SiO2) was synthesized to immobilize laccase from Trametes versicolor. The laccase treatment led to increases in the molecular weight of lignin, which facilitated its removal from PHL. The results showed that laccase activity remained at 65% after seven successive recycle runs. The combination of 10 wt.% fresh immobilized laccase and 90 wt.% recycled immobilized laccase at the overall dosage of 1 U/mL led to 34% lignin removal, irrespective of the recycling runs. The laccase treatment caused 13 wt.% sugar losses from PHL. Based on the results, a process for removing lignin from PHL was proposed based on the application and recovery of an immobilized laccase system.