POLYPEPTIDES HAVING DEMETHYLATING ACTIVITY

The present invention relates to fungal enzymes, more in particular of polyphenoloxidases (PPOs), and is based on a newly discovered enzymatic activity of a class of PPOs, i.e. de-methylation of R-substituted mono- or di-methoxyphenolsuch as present in lignin, lignin derived compounds and/or in lignocellulosic biomass. This newly discovered enzymatic activity renders these enzymes highly suitable for a plethora of applications in industry. Provided herein are methods of demethylation, processes to increase the reactivity of lignin or lignin-comprising biomass, processes of conversion lignin or lignin comprising biomass to value added products, processes for degrading and/or modifying (hemi-)cellulose in a hemicellulose-comprising substrate, and expression vectors, host cells and liquids, pastes or solid formulations and compositions for use in the demethylation method of the invention.