Potential of laccase for modification of Eucalyptus globulus wood: a XPS study

The influence of a commercial laccase on the grafting of 4-chloro-2-methoxyphenol, a model compound, onto Eucalyptus globulus sapwood was evaluated by X-ray photoelectron spectroscopy. The grafting was carried out on extracted and non-extracted wood samples. The extraction procedure modified the surface composition due to extractives removal but with high data dispersion. The laccase-mediated grafting of the chlorophenol was demonstrated by the decrease in O/C ratio and the presence of Cl in wood surface after the enzymatic wood treatment. Laccase seemed to be adsorbed suggesting a possible competition between adsorption and grafting processes. The extractive compounds have no effect on the enzymatic grafting since similar Cl amount was analyzed in extracted and non-extracted wood. This enzymatic grafting methodology opens up new possibilities for wood surface modification in order to obtain new wood products with sustainable technologies and mild conditions.