Preparation and characterization of amino and carboxyl functionalized core-shell Fe3O4/SiO2 for L-asparaginase immobilization: A comparison study


Noma S. A. A. , Ulu A., KÖYTEPE S., ATEŞ B.

BIOCATALYSIS AND BIOTRANSFORMATION, vol.38, no.5, pp.392-404, 2020 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 38 Issue: 5
  • Publication Date: 2020
  • Doi Number: 10.1080/10242422.2020.1767605
  • Title of Journal : BIOCATALYSIS AND BIOTRANSFORMATION
  • Page Numbers: pp.392-404
  • Keywords: Magnetic nanoparticles, silica coating, L-asparaginase, enzyme immobilization, enhanced stability, GRAPHENE OXIDE, NANOPARTICLES, NANOCOMPOSITE, ADSORPTION, REMOVAL, MICROSPHERES, EXTRACTION, MEMBRANE, SURFACES, LACCASE

Abstract

Magnetic nanoparticles are well known as facile and effective support for enzyme immobilization since they have a high surface area, large surface-to-volume ratio, easy separation, a fast and high enzyme loading. This study aims to provide insights on whether acidic or basic modified particles are more effective for L-asparaginase (ASNase) immobilization. Therefore, amino (Fe3O4/SiO2/NH2) and carboxyl-functionalized (Fe3O4/SiO2/COOH) particles were prepared. The functional groups, crystalline structure, magnetic properties, morphology, chemical composition and thermal behaviour of the prepared modified nanoparticles were examined via Fourier-transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). Under the optimum conditions, the immobilized enzymes were more stable within a certain range of temperatures and pH values in comparison to free enzyme. On the other hand, the immobilized enzymes showed greater stability after incubation for 3 h at 50 degrees C. The free enzyme maintained only 30% of its initial activity for 4 weeks at 4 degrees C, while Fe3O4/SiO2/NH2/ASNase and Fe3O4/SiO2/COOH/ASNase retained more than 78.9% and 56.5% of initial activities under the same conditions, respectively. Moreover, Fe3O4/SiO2/NH2/ASNase (77.2%) and Fe3O4/SiO2/COOH/ASNase (57.4%) displayed excellent operational stability after 17 repeated cycles. These findings suggested that the Fe3O4/SiO2/NH2 and Fe3O4/SiO2/COOH may be utilized as efficient and sustainable supports to developed immobilized ASNase in several biotechnological applications.