Smectite Clays as Solid Supports for Immobilization of β-Glucosidase: Synthesis, Characterization, and Biochemical Properties

Abstract

Nanomaterials as solid supports can improve the efficiency of immobilized enzymes by reducing diffusional limitation as well as by increasing the surface area per mass unit and therefore improving enzyme loading. In this work, -glucosidase from almonds was immobilized on two smectite nanoclays. The resulting hybrid biocatalysts were characterized by a combination of powder X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, differential thermal analysis, and infrared spectroscopy. Biochemical studies showed an improved thermostability of the immobilized enzyme as well as enhanced performance at higher temperatures and in a wider pH range.

Hybrid Nanomaterials of Magnetic Iron Nanoparticles and Graphene Oxide as Matrices for the Immobilization of β-Glucosidase: Synthesis, Characterization, and Biocatalytic Properties

“…On the contrary, the highest activity of immobilized bgl was achieved when graphene oxide and iron nanoparticles were used together as hybrid immobilization matrices. The high surface area of GO leads to specific interactions with the enzyme, which may induce conformational changes in the protein, leading to an increased hydrolytic activity (Serefoglou et al, 2008;Patila et al, 2013). Moreover, the small size of iron nanoparticles, as well as their high specific surface area, increases the flexibility of the enzyme, which in turn induces a high hydrolytic activity (Abraham et al, 2014).…”

Enzyme Immobilization on Layered and Nanostructured Materials

“…It was proposed that some side chains of amino acid residues of the enzyme take part in intercalation, while the polypeptide backbone is localized outside the pores. More specifi cally, the adsorption of different enzymes as α -amylase [25] , glucoamylase [26] , invertase [62] , β -glucosidase [58] and Candida antarctica lipase B ( CALB ) (see also Chapter 3 ) [56] over synthetic or natural clays is in accordance with this theory.…”

“…In most cases, as enzyme loading increases, the intensity of the refl ection increases, confi rming enhanced intercalation of enzyme or a higher degree of ordering [25,58] , while other studies showed that the enzyme loading leads to exfoliated nanocomposite structures [56,57] . In the case of organo -modifi ed clays, the interaction between the clay and the surfactant led to a shift of the d 001 diffraction peak of the organo -modifi ed clay toward lower 2 θ values, implying the expansion of the interlayer space due to the alkylammonium intercalation [56] .…”

“…A combination of techniques, such as powder X -ray diffraction ( XRD ) [56,58] , thermogravimetric analysis ( TGA ) [57] , differential thermal analysis ( DTA ) [57] , X -ray photoelectron spectroscopy ( XPS ) [56,58] , scanning electron microscopy ( SEM ) [26,57] , Fourier transform infrared ( FT -IR ) spectroscopy [57,58] and BET N 2 adsorption measurements [67] , was used for structural characterization of the enzyme -clay conjugates.…”

“…FT -IR is another tool to confi rm the successful immobilization of an enzyme on a solid support [57,58,68] . More specifi cally, the binding can be confi rmed by the FT -IR spectra of the immobilized enzyme onto various modifi ed and unmodifi ed clays, in which are presented all the characteristic bands of clays and protein [58,64,68] .…”