| Autor: |
Kamran A; 1Georg-August University School of Science (GAUSS), Georg-August-University Goettingen, Göttingen, Germany.; 2Department of Biotechnology, University of Karachi, Karachi, 75270 Pakistan., Bibi Z; 3Department of Biotechnology, Federal Urdu University of Arts, Science and Technology (FUUAST), Gulshan-e-Iqbal Campus, Karachi, 75300 Pakistan., Aman A; 4The Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, Karachi, 75270 Pakistan., Ul Qader SA; 5Department of Biochemistry, University of Karachi, Karachi, 75270 Pakistan. |
| Abstrakt: |
The β-galactosidase is an industrially valuable enzyme and used to hydrolyze the lactose into glucose and galactose. Considering the broad utility profile in food industry, β-galactosidase from Aspergillus nidulans was purified and characterized in term of its catalytic properties and stability. It displayed highest catalytic efficiency at 60 °C after 10.0 min within acidic pH environment (pH 5). The β-galactosidase exhibited 100% and 60% catalytic activity at 40 °C and 50 °C, respectively even after 120.0 min. The β-galactosidase activity was remained stable in the presence of Zn 2+ , Ni 2+ , and Mg 2+ ions. The activity was also retained in all investigated organic solvents except DMSO at various ionic concentrations. The surfactants Triton X-100 and SDS caused positive impact on the catalytic activity of enzyme at 1.0 mM concentration. However, the percent relative activity of β-galactosidase was significantly reduced when incubated with EDTA. The molecular mass of β-galactosidase estimated to be 95 kDa. The SEM micrographs of ONPG before and after β-galactosidase treatment indicated a remarkable difference in the morphology and proved the strong catalytic strength of enzyme. The β-galactosidase also demonstrated exceptional storage stability at - 80 °C, - 20 °C and 4 °C by retaining 86, 79 and 70% activity even after 100.0 days. |
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