Veratryl alcohol degradation by a catechol-driven Fenton reaction as lignin oxidation by brown-rot fungi model

Dihydroxybenzenes reduce Fe(III) to Fe(II), which react with H2O2 driving a Fenton reaction. This non-enzymic mechanism operates in wood degradation by brown-rot fungi, which mainly degrade wood carbohydrates and, to a lesser extent, lignin. Consequently, less attention has been focussed on lignin transformation by these organisms. In this work, the degradation of veratryl alcohol (VA), the simplest lignin model compound, via a Fenton reaction driven by 1,2-dihydroxybenzene (catechol, CAT) was studied. Multivariate analysis performed in order to determine the relationship between pH and concentrations of CAT, FeCl3 and H2O2 showed that the highest VA degradation, 1 mol base, was obtained at the CAT:FeCl3:H2O2 ratio of 0.375:0.375:5.0 at pH 3.4. Under these reaction conditions, VA degradation and mineralisation were, respectively, 3.8 and almost 40 times greater than for a Fe(II)-Fenton reaction.