Enzyme-Assisted Delignification of Several Pulps by Laccase from Botrytis Cinerea

The two stage laccase-assisted delignification process led to significant lignin removal in the non-pressurized treatments. It is clearly shown that an alkaline extraction prior to the second laccase treatment significantly increased the overall delignification by ∼15%. This is in line with the contention that the residual lignin has undergone structural changes during the alkaline extraction, and the resulting modified structures are susceptible to the laccase oxidation. In phenolic hydroxyl group, the pre- methylated sample was very responsive to the delignification process. The phenolic hydroxyl groups could be increased during side chain cleavage catalyzed by laccase. This finding demonstrates that the delignification oi etherified structures is an important reaction in the delignificaton by laccase.