Hierarchically macro/mesoporous silica sphere: A high efficient carrier for enzyme immobilization

Abstract

In the present study, a hierarchically macro/mesoporous silica was fabricated, characterized and evaluated as a potential carrier for enzyme immobilization. The silica contained bicontinuous structure of skeletons and macropores, which were interwoven, thus forming a highly porous network. This unique structure rendered the silica as an efficient carrier for many applications, especially in which fast mass transfer was required. Herein, it was used as the carrier to immobilize catalase (CAT) for the catalytic purpose. The CAT loading amount can reach 285 mg/g (enzyme/carrier). As expected, the catalytic efficiency/activity of the immobilized catalase (IMCAT) was quite high (Km value of 176.54 mM), which was comparable with that of the free CAT (Km value of 169.78 mM). Additionally, the temperature and pH stability of IMCAT was almost the same as free CAT. However, it is noteworthy that, the IMCAT can be retrieved for repetitive usage. After 20 cycles, IMCAT still possessed relative activity more than 50%. The proposed hierarchically macro/mesoporous silica was demonstrated to be a promising carrier for enzyme immobilization and application, with high loading amount, excellent stability and desirable repeatability.