BIOCATALYSTS OBTAINED BY ENZYME IMMOBILIZATION ON FUNCTIONALIZED MESOPOROUS SILICA SUPPORTS

Three mesoporous silica (MCM-41, MCM-48 and SBA-15), with different surface properties, pore size and porous structure, were synthesized and used as supports for laccase immobilization. The supports were functionalized with 3-aminopropyl-triethoxysilane (APTES) and 3-glycidyloxypropyltrimethoxy-silane (GPTMS). Laccase immobilization was carried out through physical adsorption and covalent binding on functionalized mesoporous silica with different textural properties. The obtained materials were characterized by X-ray diffraction at small angle, SEM and TEM microscopies, thermal analysis, N-2 adsorption-desorption, UV-Vis and FTIR spectroscopies. Immobilization yield and relative activity of laccase varied with pore size, functionalization and support pretreatment. The best values for these parameters were obtained for SBA-15 support functionalized with GPTMS after its pretreatment with glutaraldehyde. The influence of pretreatment time was also evidenced. The obtained biocatalysts were tested in oxidation of anisole and phenol with H2O2. The obtained results sustain the effect of support and method of immobilization on catalytic performances and biocatalysts stability.