Monitoring oxidation-reduction potential of laccase-mediator system: can the efficiency of a redox mediator for deslignifying kenaf pulp be predicted?

Abstract

The oxidative ability of five phenolic compounds (acetosyringone, syringaldehyde, p-coumaric acid, vanillin and actovanillone) and the laccase–mediator systems was determined by monitoring the oxidation–reduction potential (ORP) during solution oxidation and kenaf lignin oxidation process. The results confirmed the production of phenoxy radicals of variable reactivity and stressed the significant role of lignin structure in the enzymatic process. Although changes in ORP were correlated with the oxidative ability of the mediators, pulp properties determined after the bleaching stage were also influenced by condensation and grafting reactions.