Facile immobilization of enzyme on three dimensionally ordered macroporous silica via a biomimetic coating

This study describes a general strategy using norepinephrine (NE) as a stable anchor for the immobilization of enzyme onto three-dimensionally ordered macroporous (3DOM) silica. Penicillin G acylase (PGA) was chosen as a model enzyme. The effect of pH and temperature on the activity of PGA@PN–SiO2 (PGA immobilized on poly(norepinephrine)-modified 3DOM silica) was investigated. The operational stability, storage stability and kinetic properties of the PGA@PN–SiO2 were also examined. Compared with free PGA and PGA@SiO2 (PGA immobilized on blank 3DOM silica through physical adsorption), the stabilities of PGA@PN–SiO2 were improved significantly. PGA@PN–SiO2 retained high activity during the hydrolysis in a continuous packed-bed reactor (PBR) after 30 catalytic cycles, which demonstrated that PGA@PN–SiO2 can bear endurance of continuous catalysis. The method presented in this study has broad potential for immobilizing enzymes and other biomolecules.