Comparative study on functionalized SBA-15 and SBA-16nanostructured materials used for immobilization of D-amino acidoxidase

摘要

SBA-15 and SBA-16 nanostucrured materials were synthesized via hydrothermal treatment and were functionalized with3-aminopropyltriethoxysilane (APTES), and vinyltriethoxysilane (VTES). The obtained samples were characterized bydifferent techniques such as XRD, BET, IR and TEM. After functionalization, it showed that these nanostrucruredmaterials were still maintained the hexagonal pore structure of the parent SBA-15 and cubic cage structure of the parentSBA-16. The non-functionalized pure silica SBA-15 and SBA-16 as well as functionalized SBA-15 and SBA-16materials were used to immobilize DAAO, which is industrially important enzyme for the production of glutaryl 7-aminocephalosporanic acid (GL-7-ACA) from cephalosporin C (CPC). The obtained results revealed that functionalized SBA-15 and SBA-16 materials exhibited higher enzymatic activity and stability than those of non-functionalized ones. Thismight be due to the enhancing of surface hydrophobicity upon functionalization. The surface functionalization of thenanostructured silicas with organic groups can enhance the interaction between enzyme and the supports andconsequently increasing the operational stability of the immobilized enzyme. The loading of enzyme on SBA-15materials was higher than that on SBA-16 samples (both functionalized and non-functionalized types). This might beexplained by the difference in pore size and type (cylindrical for SBA-15 and bottle-neck for SBA-16) as well asstructure shape (hexagonal for SBA-15 and cubic cage for SBA-16) of both mesoporous materials. Additionally, natureof functionalized groups significantly affected the enzymatic activity. Effects on surface binding force, nature offunctional groups, pore size of supports were investigated and discussed.