Layer-by-Layer coated tyrosinase: An efficient and selective synthesis of catechols

Agaricus bisporous tyrosinase was immobilized on commercial available epoxy-resin Eupergit (R) C250L and then coated by the Layer-by-Layer method (LbL). The two novel heterogeneous biocatalysts were characterized for their morphology, pH and storage stability, kinetic properties (K-m, V-max, V-max/K-m) and reusability. These biocatalysts were used for the efficient and selective synthesis of bioactive catechols under mild and environmental friendly experimental conditions. Ascorbic acid was added in the reaction medium to inhibit the formation of ortho-quinones, thus avoiding the known enzyme suicide inactivation process. Catechols were obtained mostly in quantitative yields and conversion of substrate. Tyrosinase immobilized on Eupergit (R) C250L and coated by the LbL method showed better catalytic activities, higher pH and storage stability, and reusability with respect to immobilized uncoated tyrosinase. Since chemical procedures to synthesize catechols are often expensive and with high environmental impact, the use of immobilized tyrosinase represents an efficient alternative for the preparation of this family of bioactive compounds. (C) 2011 Elsevier Ltd. All rights reserved.