Covalent Immobilization of Candida antarctica Lipase B on Functionalized Hollow Mesoporous Silica Nanoparticles

Abstract

Candida antarctica lipase B (CALB) produced by recombinant Pichia pastoris was covalently immobilized to a carboxylfunctionalized hollow mesoporous silica sphere (HMS) synthesized by sol-gel precipitation. The HMS was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometer (XRD), and Brunauer-Emmett-Teller (BET). The immobilized CALB was characterized through Fourier transform infrared spectra (FT-IR) and elemental analysis to verify the binding of enzyme. The free and immobilized CALB were tested in tributyrin hydrolysis. Results revealed that CALB loading capacity of HMS-COOH was about 28.6 mg/g support and the corresponding enzyme activity was up to about 2700 U/g support at optimal pH and temperature, which was 6.5 and 30°C respectively. Moreover, compared with free CALB, the immobilized CALB presented more resistant towards the reaction pH and temperature changes. Furthermore, the immobilized CALB retained 60 % residual activity after eight batches of recycling and exhibited better thermal stability and storage stability, which was promising in the potential industrial applications.