Improvement of stability and reusability of α-amylase immobilized on naringin functionalized magnetic nanoparticles: A robust nanobiocatalyst.

Enzyme immobilized on magnetic nanoparticles (MNPs) can be used as efficient recoverable biocatalysts under strong magnetic responses. In the present work, α-amylase was immobilized onto naringin functionalized MNPs via ionic interactions. For this purpose, the MNPs were functionalized with naringin, as a biocompatible flavonoid. The morphology, structure, and properties of functionalized MNPs and the immobilization of α-amylase on synthesized nanocomposite were characterized through different analytical tools including TGA, VSM, FTIR, SEM-EDX and TEM. Furthermore, the optimum conditions of temperature, pH, reaction time and enzyme concentration for immobilization process were investigated. The results showed that the optimal conditions for immobilization of α-amylase onto synthesized nanocarrier occurred at pH6.5 and 55°C. The reusability experiments revealed high activity maintenance of immobilized α-amylase even after 10 reaction cycles. Moreover, the storage stability of immobilized enzyme improved via immobilization in comparison with free one and it maintained 60% of its initial activity after 6weeks storage at 4°C. The improvements in enzyme catalytic properties via immobilization made this nanobiocatalyst as a good candidate in bio-industrial applications. Furthermore, the synthesized nanocomposite would have the potential for practical applications in other and binary enzyme immobilization.