Preparation of Nano-Sized Mesoporous Silica and Its Application in Immobilization of β-galactosidase from Aspergillus Oryzae

In alkaline conditions, monodisperse nano-sized mesoporous silica was synthesized using cetyl trimethyl ammonium bromide (CTAB) as template and tetraethoxysilane (TEOS) silica as source in ethanol / water cosolvent conditions. Using method of nitrogen adsorption, specific surface area of the dried monodisperse nano-sized mesoporous silica was about 1591 m 2 /g and the pore size was about 3.8 nm. The field-emission scanning electron microscope (SEM) micrographs showed that the silica particles obtained were spherical with an approximate diameter of 160 nm and of good dispersion. Transmission electron microscopy (TEM) revealed that the carrier had an excellent cellular structure with disordered multi-channels and smooth surface. The nano-sized mesoporous silica above was employed to immobilize β-galactosidase from aspergillus oryzae for the first time. At the experimental conditions in section 2.4, the enzyme activity and the activity yield were 535.11 U/g dry carrier and 79.63%, respectively. Kinetic data of the immobilized enzyme such as optimum temperature, pH, and thermal and pH stability among other valuable results were also determined.