Novel and efficient method for immobilization and stabilization of β-D-galactosidase by covalent attachment onto magnetic Fe3O4-chitosan nanoparticles

作者：Pan, Chenliang; Hu, Bing; Li, Wei; Sun, Yi; Ye, Hong; Zeng, Xiaoxiong^*

来源：Journal of Molecular Catalysis B: Enzymatic , 2009, 61(3-4): 208-215.

DOI：10.1016/j.molcatb.2009.07.003

• Magnetic Fe3O4 nanoparticle
• Chitosan
• beta-D-Galactosidase
• Immobilization
• Galactooligosaccharide

A novel and efficient immobilization of beta-D-galactosidase from Aspergillus oryzae has been developed by using magnetic Fe3O4-chitosan (Fe3O4-CS) nanoparticles as support. The magnetic Fe3O4-CS nanoparticles were prepared by electrostatic adsorption of chitosan onto the surface of Fe3O4 nanoparticles made through co-precipitation of Fe2+ and Fe3+. The resultant material was characterized by transmission electron microscopy. X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry and thermogravimetric analysis. beta-D-Galactosidase was covalently immobilized onto the nanocomposites using glutaraldehyde as activating agent. The immobilization process was optimized by examining immobilized time, cross-linking time, enzyme concentration, glutaraldehyde concentration, the initial pH values of glutaraldehyde and the enzyme solution. As a result. the immobilized enzyme presented a higher storage, pH and thermal stability than the soluble enzyme. Calactooligosaccharide was formed with lactose as substrate by using the immobilized enzyme as biocatalyst, and a maximum yield of 15.5% (w/v) was achieved when about 50% lactose was hydrolyzed. Hence, the magnetic Fe3O4-chitosan nanoparticles are proved to be an effective support for the immobilization of beta-D-galactosidase.

• 出版日期2009-12
• 单位南京农业大学