Covalent enzyme immobilization on magnetite particles modified with lemon peel extracts

Enzymes are biocatalysts that have a wide range of applications including biosensors [1], water treatment [2], therapeutics [3], etc., due to their properties such as selectivity and non-toxicity. The widespread use of enzymes in industry is often hampered by their low stability over time, shelf life, recovery, and reusability. In addition, enzymes are susceptible to denaturation due to external influences such as pH, temperature, presence of metal ions and organic solvents, which further increase their cost. These disadvantages can be overcome by immobilizing enzymes on various solid supports, such as magnetite particles [2]. The properties of both the enzyme and the solid support material determine the overall properties of the immobilized enzyme. In general, enzymes (peroxidases) immobilized on magnetic solid supports have been shown to exhibit greater stability and reusability than peroxidases immobilized on non-magnetic supports [4]. In this work, the suitability of biofunctionalized magnetite particles as a solid support for the immobilization of pure horseradish peroxidase is investigated. Biofunctionalized magnetite particles were synthesized from iron salts in the presence of aqueous lemon peel extracts by the co-precipitation method. The lemon peel extracts were prepared with water in a subcritical condition (temperature 140°C and autogenous pressure) for 10 minutes. The XRD and FTIR methods confirmed that the magnetite particles were synthetized. The magnetite particles were used as support for the immobilization of peroxidase with glutaraldehyde as a crosslinker. The obtained immobilized enzyme showed high enzymatic activity (10.5 U/g), with the highest activity measured at pH 6 and a temperature of 50-60°C. The obtained biocatalyst can be used in various environmental processes. References [1] Qin, X. et al. Analyst 2012, 137, 939-943. [2] Petronijević, M. et al. Int. J. Environ. Sci. Technol. 2024, 21, 3899-3912. [3] Khan, S. et al. J. Adv. Res. 2021, 33, 227-239. [4] Khalid, N. et al. Int J Biol Macromol 2022, 207, 387-401.