Enzymatic oxidation of lignosulfonates and hydroxycinnamic acids/xylan associated to adhesives preparation

Abstract

The current project aims to integrate lignosulfonate and xylan production in a biorefinery processing sugarcane bagasse, and explores the transformation of the lignosulfonates and hydroxycinammic acids linked to xylans through enzymatic and chemical reactions to produce adhesives. The experimental approach of the project can be divided into two main frameworks: 1) The oxidative transformation of lignosulfonates and hydroxycinammic acids linked to xylans will be developed by using laccases, polyphenol-oxidases and tyrosinases. These oxidative transformations will be performed in situ during adhesion of wood veneers to evaluate the quality of the reticulated macromolecules as adhesives for wood fibers. The expectation is that the lignosulfonates and the xylans, being water soluble, could infiltrate adjacent fiber cell walls, and their enzymatic cross-link would increase their molar masses, as well as would promote new covalent bonds between lignosulfonates and xylans with the lignin contained in the fiber cell walls providing fiber adhesion. 2) Another alternative to be evaluated in the project would be to use the lignosulfonates or their enzymatic transformation products as phenol precursors in the preparation of epoxy resins through reaction with epichlorohydrin. Prepared epoxy resins would be further cross-linked with aliphatic amines to provide new thermosets with high wood adhesion capacity. Overall, the project will develop a biorefinery model that includes production of lignosulfonates and xylans useful for preparing wood adhesives. The use of these new materials for fiber adhesion in fiberboards and plywood production is envisaged as new uses of biomass derived compounds. (AU)