Characterization of immobilized β-galactosidase from Aspergillus niger

Karzan T. Mahmood, Waleed A. Mahmood
2013 Delta Journal of Science  
β-galactosidase enzyme was isolated from Aspergillus niger, and immobilized in sodium alginate gel. The maximum activity of the free enzyme was obtained at 65 o C, pH 3.5 and its not affected by immobilization. The free enzyme had pH stability range from 3.5 to 6.5 and it was increased by immobilization process especially at acid pH values. The free enzyme retained 90.28, 85.09, 45.49, and 19.2 % of its initial activity after incubation at 30, 40, 50, and 60 o C, for 60 min respectively.
more » ... espectively. Thermal stability was enhanced by immobilization process. The kinetic parameters for soluble and immobilized enzyme were also determined, and immobilization led to decrease in Km value (5.12 mM for free form to 1.48 mM for immobilized form), indicating decreased affinity by the enzyme for its substrate. Vmax was also decreased by immobilization process, and it was reached from 86.66 μmol ONP.min -1 for free enzyme to .38.02 μM ONP.min -1 for immobilized form.
doi:10.21608/djs.2013.139571 fatcat:htsmllfvqnaf3d7okzjkoqckz4