10 3 2 benzenediol oxygen oxidoreductase catalyze the oxidation of o and p substituted phenolic hydroxyl and amino amine groups in monomeric and polymeric aromatic compounds the oxidative reaction leads to the formation of phenoxy radicals and finally to the polymerization of lignin and possibly the carbohydrate matter in the method of the present invention the enzyme used may be any of the enzymes catalyzing the biological radical formation and secondary chemical polymerization of low molecular weight lignins such as laccase tyrosinase peroxidase or oxidase as specific examples of oxidases the following can be mentioned laccases ec 1 10 3 2 catechol oxidases ec 1 10 3 1 tyrosinases ec 1 14 18 1 and bilirubin oxidases ec 1 3 3 5 laccases are particularly preferred oxidases they can be obtained from bacteria and fungi belonging to e g the following strains aspergillus neurospora podospora botrylis lentinus polyporus rhizoctonia coprinus coriolus phlebia pleurotus fusarium and trametes suitable peroxidases can be obtained from plants or fungi or bacteria preferred peroxidases are those which originate from plants in particular horseradish peroxidase and soy bean peroxidase the terms u201c surfactant u201d or u201c surface active agent u201d are synonymously used to designate compounds which have affinity to water and to hydrophobic e g fatty materials thus helping the hydrophobic materials to suspend in water medium density fiberboards abbreviated mdf are used for construction and in furniture manufacturing it is produced as panels having thicknesses in the range of 2 5 to 40 mm or even more in comparison to particle boards mdf processes give panels having higher strength and a more homogeneous structure than particle boards referring to the attached drawing a preferred process embodiment according to the present invention for producing mdf boards comprises the following steps.