3rd TAGRA

In this study, magnetic magnetite nanoparticles were synthesized and modified for the covalent immobilization of lipase. Magnetic nanoparticles have attracted considerable attention due to their applications in catalysis, water treatment, biotechnology, biomedicine, and drug delivery. Magnetite nanoparticles with an approximate size of 10–20 nm were prepared using the co-precipitation method under optimized conditions. The synthesis was conducted in an alkaline medium under a nitrogen atmosphere to minimize the oxidation of Fe(II) ions and prevent the formation of unwanted iron oxide phases. The synthesized nanoparticles were characterized by infrared (IR) spectroscopy and subsequently coated with silica using a sol-gel process involving tetraethyl orthosilicate (TEOS). The silica coating protected the magnetic core and provided a suitable surface for functionalization. The nanoparticles were further modified with 3-aminopropyltriethoxysilane (APTES) to introduce amino groups and improve surface properties, facilitating enzyme attachment. Lipase was covalently immobilized onto the functionalized magnetic nanoparticles. This approach aims to improve enzyme stability, facilitate magnetic separation, and enable enzyme recovery and reuse. The high surface-to-volume ratio of nanoparticles also provides favorable conditions for enzyme loading and catalytic performance. IR spectroscopy was used to characterize the nanoparticles at different stages of synthesis and modification. Characteristic absorption bands associated with Fe–O and Si–O bonds confirmed the formation of magnetite and the silica coating, while changes in the spectra indicated successful surface functionalization and enzyme immobilization. Finally, atomic absorption spectroscopy was employed to compare free and immobilized lipase and investigate parameters affecting enzyme performance. The study highlights the potential of functionalized magnetic nanoparticles as effective supports for enzyme immobilization, offering advantages in enzyme recovery, operational stability, and reusability.