Immobilization of Laccase in Glycidoxypropyl-Functionalized Magnetic Mesoporous SiO2/Fe3O4 Hollow Microspheres

Glycidoxypropyl-functionalized magnetic mesoporous SiO2/Fe3O4 hollow microspheres (FMMS) with various amounts of terminally bonded groups in the pore channels were synthesized by the co-condensation of tetraethoxysilane (TEOS) and 3-glycidoxypropyltrimethoxylsilane (GPTMS) in the presence of cetyltrimethylammonium bromide (CTAB) and 1,3,5-triisoporpylbenzene (TMB), and utilized as supports for laccase immobilization. It is revealed that glycidoxypropyl groups have been successfully covalently attached to the pore wall of magnetic mesoporous SiO2/Fe3O4 hollow microspheres (MMS). The magnetic mesoporous SiO2/Fe3O4 microspheres (sample10%FMMS) have a saturation magnetization of 13.6 emu·g-1 and a low coercivity (50 Oe). The functional materials preserve a mesoscopic ordering at a concentration of GPTMS as high as 15%. The BET surface area and pore volume of the functionalized materials decrease with increasing amount of GPTMS, but a desirable pore structure remains when the GPTMS amount increases to 10%. The 10%FMMS material exhibits higher laccase immobilization and stability than pure MMS because of the covalent interaction between the amino groups of laccase and the epoxy groups of the functional MMS.