A unique interface-binding chloroperoxidase (CPO) was developed and examined for interfacial biocatalysis. Native CPO was conjugated with polystyrene (PS) to form a surfactant-like structure that self assembled at oil-water interfaces. While enantioselectivity of the enzyme was maintained, the interfacial assembly of the enzyme improved its overall catalytic efficiency as compared to that observed with the enzyme contained in the bulk aqueous phase. The PS conjugated CPO (PS-CPO) showed a 2.5-fold enhancement of enzyme productivity versus native CPO under batch reaction conditions for the epoxidation of styrene, whereas a 25-fold improvement was realized in a continuous feeding reaction to reach a productivity of 10 μmol h-1 mg protein-1. The interface-binding enzyme also demonstrated several other advantages such as suppressing unwanted side reactions including the hydrolysis of styrene epoxide products, stabilizing the enzyme by limiting its exposure to both the oxidant H2O2 and epoxide products, and alleviating the deactivating effect of interfacial stress on enzymes by functioning as a surfactant.
Bibliographical noteFunding Information:
This work was supported by grants from the American Chemical Society PRF program (36726-G4) and the National Science Foundation (CTS–0214769). The authors thank Bio-Research Products Inc. for providing chloroperoxidase and Drs. Jeffery S. Kanel and Bi-min Zhang Newby for valuable discussions.
- Biphasic reaction
- Interfacial biocatalysis
- Styrene epoxidation