Trypsin Immobilization on Thiol Functionalized Mesoporous Silicas Prepared Using Castor Oil Template

Abstract

Mesoporous thiol modified silicas have been prepared using castor oil as a templating agent. The preparation was done through a co-condensation of 3-mercaptopropyltriethoxysilane and tetraethylorthosilicate in a 1:4 molar ratio. Physisorption studies showed that the prepared mesoporous silicas have an average pore diameter of 9 nm, pore volume of 1.0336 cm3/g and surface areas of up to 605 m2/g. FTIR confirmed the attachment of thiol groups on the surface of the prepared mesoporous silica as evidenced with an absorption band at around 2600 cm–1. SEM images indicated agglomeration of the prepared particles. The prepared thiol modified silicas were successfully immobilized with trypsin enzyme. The immobilized trypsin enzyme was stable and active for hydrolysis of N-α-benzoyl-DL-arginine-p-nitroanilide (BAPNA) substrate. Re-use studies of the immobilized trypsin showed that the enzyme could be reused up to four cycles without significant loss of activity.

Keywords: Castor oil; Template; Mesoporous silica; Thiol; Trypsin; Enzyme immobilization;