Active Biocatalysts Based on Pepsin Immobilized in Mesoporous SBA-15

Porcine pepsin was immobilized inside the SBA-15 mesoporous silica system through physical adsorption. A grafting step with 3-aminopropryltriethoxysilane (APTES) was performed to reduce the pore openings of the host material, in order to minimize the enzyme leaching. A detailed physical chemical characterization of hybrid materials was performed. The catalytic activity of the hybrid bioinorganic material, tested with two different substrates (hemoglobin and Z-L-glutamyl-L-tyrosine dipeptide), confirmed that pepsin was located inside the pore/channels of the silica material and that the grafting process did not affect the enzyme structure. The immobilized pepsin has maintained the necessary degree of freedom to fulfill its catalytic activity. The reusability of the so-called bioreactor was also investigated.