Jump to main content
Jump to site search

Issue 58, 2016, Issue in Progress
Previous Article Next Article

Graphene based magnetic nanocomposites as versatile carriers for high yield immobilization and stabilization of β-galactosidase

Author affiliations

Abstract

The present study demonstrates an efficient method for high yield immobilization of Aspergillus oryzae β-galactosidase onto graphene-iron oxide nanocomposites (Gr@Fe3O4 NCs) by a simple adsorption mechanism. The synthesized nanocomposites were characterized by X-ray diffraction and FT-Raman spectroscopy, and by vibrating sample magnetometry. The binding of the enzyme onto the nanocomposites was confirmed by transmission electron microscopy, scanning electron microscopy, and Fourier transform-infrared spectroscopy. The bound enzyme showed 90% immobilization yield. The adsorbed and free enzyme both exhibited the same pH-optima at pH 4.5. However, the immobilized enzyme showed enhanced pH stability toward acidic and basic extremes, as well as increased temperature resistance as compared to native β-galactosidase. The Michaelis constant, Km decreased, while Vmax increased, which indicates a higher affinity and activity retention by immobilized β-galactosidase. The bound enzyme retained 83% activity even after its 8th successive reuse. The adsorbed enzyme lost only 21% of its initial activity during storage at 4 °C, while the free β-galactosidase retained only 49% activity under similar storage conditions. The genotoxicity assessment revealed that the nanocomposites showed negligible toxicity to pBR322 DNA plasmid and human lymphocytes. In view of its easy production, non-toxic nature, improved stability against various denaturants and excellent reusability, the versatile Gr@Fe3O4 NCs can serve as an ideal support for the immobilization of other enzymes as well, and it may find applications in constructing biosensors and producing lactose-free dairy products to feed lactose intolerant patients.

Graphical abstract: Graphene based magnetic nanocomposites as versatile carriers for high yield immobilization and stabilization of β-galactosidase

Back to tab navigation

Supplementary files

Publication details

The article was received on 16 Mar 2016, accepted on 26 May 2016 and first published on 27 May 2016


Article type: Paper
DOI: 10.1039/C6RA06960F
RSC Adv., 2016,6, 53493-53503

  •   Request permissions

    Graphene based magnetic nanocomposites as versatile carriers for high yield immobilization and stabilization of β-galactosidase

    M. Khan, Q. Husain and A. H. Naqvi, RSC Adv., 2016, 6, 53493
    DOI: 10.1039/C6RA06960F

Search articles by author

Spotlight

Advertisements