Enhancement of Thermostability of <i>Aspergillus flavus</i> Urate Oxidase by Immobilization on the Ni-Based Magnetic Metal–Organic Framework
Neda Motamedi,
Mahmood Barani,
Azadeh Lohrasbi-Nejad,
Mojtaba Mortazavi,
Ali Riahi-Medvar,
Rajender S. Varma,
Masoud Torkzadeh-Mahani
Affiliations
Neda Motamedi
Department of Biotechnology, Institute of Science High Technology & Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631133131, Iran
Mahmood Barani
Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman 7616913555, Iran
Azadeh Lohrasbi-Nejad
Department of Agricultural Biotechnology, Shahid Bahonar University of Kerman, Kerman 7616914111, Iran
Mojtaba Mortazavi
Department of Biotechnology, Institute of Science High Technology & Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631133131, Iran
Ali Riahi-Medvar
Department of Molecular and Cell Biology, Faculty of Basic Sciences, Kosar University of Bojnord, Bojnord 9415615458, Iran
Rajender S. Varma
Regional Centre of Advanced Technologies and Materials, Czech Advanced Technology and Research Institute, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic
Masoud Torkzadeh-Mahani
Department of Biotechnology, Institute of Science High Technology & Environmental Sciences, Graduate University of Advanced Technology, Kerman 7631133131, Iran
The improvement in the enzyme activity of Aspergillus flavus urate oxidase (Uox) was attained by immobilizing it on the surface of a Ni-based magnetic metal–organic framework (NimMOF) nanomaterial; physicochemical properties of NimMOF and its application as an enzyme stabilizing support were evaluated, which revealed a significant improvement in its stability upon immobilization on NimMOF (Uox@NimMOF). It was affirmed that while the free Uox enzyme lost almost all of its activity at ~40–45 °C, the immobilized Uox@NimMOF retained around 60% of its original activity, even retaining significant activity at 70 °C. The activation energy (Ea) of the enzyme was calculated to be ~58.81 kJ mol−1 after stabilization, which is approximately half of the naked Uox enzyme. Furthermore, the external spectroscopy showed that the MOF nanomaterials can be coated by hydrophobic areas of the Uox enzyme, and the immobilized enzyme was active over a broad range of pH and temperatures, which bodes well for the thermal and long-term stability of the immobilized Uox on NimMOF.
