Immobilization of β-d-galactosidase from Kluyveromyces lactis on functionalized silicon dioxide nanoparticles: Characterization and lactose hydrolysis

Madan Verma, Colin Barrow, J. F. Kennedy, Munish Puri

    Research output: Contribution to journalArticle

    57 Citations (Scopus)

    Abstract

    β-d-Galactosidase (BGAL) from Kluyveromyces lactis was covalently immobilized to functionalized silicon dioxide nanoparticles (10-20nm). The binding of the enzyme to the nanoparticles was confirmed by Fourier transform-infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Functionalized nanoparticles showed 87% immobilization yield. Soluble and immobilized enzyme preparation exhibited pH-optima at pH 6.5 and 7.0, respectively, with temperature optima at 35 and 40°C, respectively. Michaelis constant (K m) was 4.77 and 8.4mM for free and immobilized BGAL, respectively. V max for the soluble and immobilized enzyme was 12.25 and 13.51U/ml, respectively. Nanoparticle immobilized BGAL demonstrated improved stability after favoring multipoint covalent attachment. Thermal stability of the immobilized enzyme was enhanced at 40, 50 and 65°C. Immobilized nanoparticle-enzyme conjugate retained more than 50% enzyme activity up to the eleventh cycle. Maximum lactose hydrolysis by immobilized BGAL was achieved at 8h.

    Original languageEnglish
    Pages (from-to)432-437
    Number of pages6
    JournalINTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
    Volume50
    Issue number2
    DOIs
    Publication statusPublished - 1 Mar 2012

    Keywords

    • Covalent binding
    • FTIR
    • Lactose hydrolysis
    • Reusability
    • SEM imaging
    • Thermal stability

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