MEDIATOR-ASSISTED SELECTIVE OXIDATION OF LIGNIN MODEL COMPOUNDS BY LACCASE FROM BOTRYTIS-CINEREA

Laccase from Botrytis cinerea catalyzes benzylic oxidations and cleava ge of lignin-related diphenylmethanes. Selective reactions with non-ph enolic 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 biotransformat ions. With unblocked phenols, ring couplings are the dominant endprodu cts either with or without mediators.