beta-Galactosidase (beta-D-galactosidase galactohydrolase, EC 3.2.1. 23) isolated and purified from gram chicken bean was immobilized on cross-linked polyacrylamide gel. The activity yield was high and attained up to 72%. Compared with the free enzyme, the immobilized enzyme had a wider operational pH range and better thermal stability. Lyophilized pieces exhibited good stability when stored at room temperature for 60 days and a favorable operational stability when used eight times repeatedly without loss of enzymatic activity under the same conditions. Kinetic data (K(m), V(m), and E(a)) for the free and the immobilized enzymes were determined using O-nitrophenyl-beta-D-galactoside (ONPG) and lactose as substrates. The result of time courses of hydrolysis of lactose showed that beta-galactosidase from the plant gram chicken bean would have a promising application in the hydrolysis of lactose in milk.

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The porous ferric GMA-DVB polymer was synthesized from glycidlymethacrylate (GMA) and divinyl benzene (DVB) by suspension polymerization with lauryl alcohol and cyclohexanol as pore-forming reagents in the presence of FeCl 3 and FeCl 2 . The structure and the magnetism of the GMA-DVB polymer beads were featured with magnetic scales, X-ray spectroscopy and scanning electron microscope (SEM). Aspergillus Oryzae β-galactosidase was bounded on the magnetic polymer under the best terms, and the maximum activity was determined to be 271.25U/g dry carries. Meanwhile, the fundamental properties about the bounded enzyme, such as the influence of temperature and pH, were assayed and the satisfactory results were got.

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.