Mediator-assisted selective oxidation of lignin model compounds by laccase from Botrytis cinerea

Laccase from Botrytis cinerea catalyzes benzylic oxidations and cleavage of lignin-related diphenylmethanes. Selective reactions with non-phenolic monomeric or beta-1-dimeric model compounds using O-2 and redox mediators can also be carried out. At substrate to mediator ratios of 5:1,1-hydoxybenzotriazole (HOBT) is 8-20 fold more effective than 2,2-azinobis-3-ethylthiazoline-6-sulfonate (ABTS) for such biotransformations. With unblocked phenols, ring couplings are the dominant endproducts either with or without mediators.