ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Immobilization of butyrylcholinesterase on chitosan/chitosan–TiO₂ via glutaraldehyde cross-linking: enzyme stability, reusability and characterization

Adem Necip

Department of Pharmacy Services, Vocational School of Health Services, Harran University, Şanlıurfa, Turkey

E-mail: ademnecip@harran.edu.tr

Received: 14 January 2025  Accepted: 15 July 2025

Abstract:

Enzymes are unstable and short-lived. This leads to decreased reusability and increased cost of enzymes. In this study, the butyrylcholinesterase (BChE) enzyme was immobilized on the chitosan surface via glutaraldehyde by the cross-linking method in which glutaraldehyde contains functional amine group. The immobilized enzyme was characterized by scanning electron microscopy–energy-dispersive X-ray analysis (SEM–EDX) and Fourier transform infrared spectra (FTIR). The working and storage stability of immobilized BChE was found to be higher than that of free enzyme by spectrophotometric method. At the end of 90 days, the free enzyme and immobilized BChE (CS/GA/BChE and CS/TiO₂/GA/BChE) enzyme retained 54%, 89% and 91% of the remaining activity, respectively. The effect of pH on free and immobilized BChE was studied in Tris buffer in the pH range from 4.0 to 12.0. The optimum pH for free and immobilized BChE was found to be 7.5. The operational stability results indicate that after 20 reuses, BChE immobilized on CS/GA and CS/TiO₂/GA carrier materials retained approximately 93% and 94% of their initial activities, respectively. The BChE enzyme is used in the analysis of pesticides, so the high stability and reusability of the enzyme as a result of immobilization processes are important in biotechnological applications.

Keywords: Butyrylcholinesterase; Chitosan–TiO2/glutaraldehyde; Enzyme immobilization; Stability; Characterization

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04256-5

Chemical Papers 79 (9) 6365–6373 (2025)