摘要：Organophosphorous Compounds (OPC) are one group of ester and amide or derivatives of toxic thiol-phosphoric compounds widely used to control insects and pests. Such compounds cause the deactivation of acetyl cholinesterase enzyme and create complications in organisms. Wild-type Organophosphorus Hydrolase (OPH) is used for the identification and detoxification of organophosphorus compounds. Immobilization of OPH enzyme on various levels is one of the most effective methods to develop identification and detoxification. As a biopolymer including reactive amine and hydroxyl groups and due to the amine groups as cationic polyelectrolyte, chitosan is particularly important and has many applications, especially in the field of immobilization. In the present study, OPH enzyme was immobilized on chitosan beads and glutaraldehyde was used as cross-linker. Binding the enzyme to chitosan beads was confirmed by Fourier Transform Infrared (FTIR) spectroscopy system and the assessment of its activity was also confirmed. The thermal stability of free and immobilized enzymes was measured in the temperature range of 25-80°C. The pH stability of free and immobilized enzymes was examined at 2-12 pH and the assessment of the reusability of immobilized enzyme was also investigated. The results showed that the thermal stability and pH of the immobilized enzyme was more than that of the free enzyme. Evaluating the reusability of immobilized enzyme indicated that the immobilized enzyme can be applied at least three times without decreasing its activity. The results of this study show the positive role of immobilizing the enzyme in increasing its activity and stability. Immobilization also increases reusability of immobilized enzyme and is economically affordable.
