Immobilization of invertase onto crosslinked poly(p‐chloromethylstyrene) beads

Abstract

ABSTRACT:Invertase was immobilized onto poly(p-chloromethylstyrene) (PCMS) beads that were produced by a suspension polymerization with an average size of 186 m. The beads had a nonporous but reasonably rough surface. Because of this, a reasonably large external surface area (i.e., 14.1 m 2 /g) could be achieved with the proposed carrier. A two-step functionalization protocol was followed for the covalent attachment of invertase onto the bead surface. For this purpose, a polymeric ligand that carried amine groups, polyethylenimine (PEI), was covalently attached onto the bead surface by a direct chemical reaction. Next, the free amine groups of PEI were activated by glutaraldehyde. Invertase was covalently attached onto the bead surface via the direct chemical reaction between aldehyde and amine groups. The appropriate enzyme binding conditions and the batch-reactor performance of the immobilized enzyme system were investigated. Under optimum immobilization conditions, 19 mg of invertase was immobilized onto each gram of beads with 80% retained activity after immobilization. The effects of pH and temperature on the immobilized invertase activity were determined and compared with the free enzyme. The kinetic parameters K M and V M were determined with the Michealis-Menten model. K M of immobilized invertase was 1.75 folds higher than that of the free invertase. The immobilization caused a significant improvement in the thermal stability of invertase, especially in the range of 55-65°C. No significant internal diffusion limitation was detected in the immobilized enzyme system, probably due to the surface morphology of the selected carrier. This result was confirmed by the determination of the activation energies of both free and immobilized invertases. The activity half-life of the immobilized invertase was approximately 5 times longer than that of the free enzyme.

Immobilization of invertase onto dimer acid‐co‐alkyl polyamine

“…5 The most frequently used carriers have been based on cellulose, glass, copolymers of polyamino acids, poly(p-chloromethylstyrene) beads, starch, agarose, crosslinked dextran, and ethylene-maleic anhydride copolymers. [6][7][8] Different polypyrrole/polytetrahyrofuran/invertase electrodes were constructed by the entrapment of invertase in conducting polymer matrices by electropolymerization. 9,10 A very large number of reactions have been used for the covalent coupling of the enzymes.…”

Invertase immobilised on montmorillonite: reusability enhancement and reduction in leaching

“…Similar result was observed by Arica et al [10] for invertase immobilised on spacer-arm attached poly(hydroxyethyl methacrylate) membrane. Bahar and Tuncel [7] found that the activity of invertase immobilised onto crosslinked poly(p-chloro methyl styrene) decreased by 20% after 25 batch experiments. Our results demonstrate better reusability characteristics for the covalently bound invertase.…”

“…Soluble invertase is used in the sweet industry in the production of artificial honey. Immobilisation of invertase on corn grits [3], polymer matrices [4][5][6][7], calcium alginate [8], composite gel fibres [9] etc., has already been reported. Studies on reusability of the immobilised enzymes are also reported.…”

Acid activated montmorillonite: an efficient immobilization support for improving reusability, storage stability and operational stability of enzymes

“…The results were compared with absorbance of standard starch and the amount converted was calculated. In case of sugar hydrolysis, colour was developed using 2% 3,5-dinitro salicylic acid solution in 1 M NaOH (w/v) and absorbance was read at 490 nm [11,36]. A standard calibration curve was constructed using glucose solution and the total reducing sugar content was estimated.…”

“…Magnetic polyvinylalcohol microspheres were also used to immobilize enzymes [10]. Other polymers like poly (p-chloromethylstyrene) [11], polypropylene [12], polypyrrole [13,14], graft co-polymers [15,16] etc. have been used efficiently.…”