The effect of external stimuli on the invertase adsorption capacity of poly(N-vinyl-2-pyrrolidone-co-itaconic acid) hydrogels

Tümtürk, H.; ̧aykara, T. C; Kantoğlu, Ö.; Güven, O.

doi:10.1002/(sici)1522-9505(19991201)273:1<1::aid-apmc1>3.3.co;2-v

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“…In literature, there are certain values given for invertase loading. For example, 4.0–18.6 mg invertase binding per gram of polymeric supports and dry gels has been reported previously (Tümtürk et al. 1999b, 2000b).…”

Section: Resultsmentioning

confidence: 60%

Covalent Immobilization of Invertase on Chemically Activated Poly (Styrene-2-Hydroxyethyl Methacrylate) Microbeads

Altinok

Aksoy

Tümtürk

et al. 2008

J Food Biochemistry

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A carrier for invertase enzyme was synthesized from styrene (S) and 2‐ hydroxyethyl methacrylate (HEMA) in the form of microbeads. These poly (styrene‐2‐hydroxyethyl methacrylate), P(S‐HEMA) microbeads were activated by epichlorohydrin (ECH) treatment for covalent immobilization. The free and immobilized invertase were assayed in the hydrolysis of sucrose to glucose, and the obtained results were compared. The optimum pH was 4.5 for free and 5.5 for immobilized invertase. The optimum temperature of invertase shifted from 45C to 55C upon immobilization. For free and immobilized enzymes, kinetic parameters were calculated as 4.1 × 10−3 mol L−1and 9.2 × 10−3 mol L−1for Km, and 6.6 × 10−2 mol L−1 min−1and 4.1 × 10−1 mol L−1 min−1for Vmax, respectively. After 1 month of storage at 4C, free enzyme retained 36% of its initial activity, while for the ECH‐activated P(S‐HEMA) immobilized enzyme, P(S‐HEMA)‐E, this value was observed as 67%. In repeated batch use, i.e., 20 times in 3 days, 78% retention of the initial activity was observed for P(S‐HEMA)‐E system. PRACTICAL APPLICATIONS Immobilization of enzymes are very important for many industrial applications, e.g., food, medicine, pharmacology, etc. Invertase converts sucrose to glucose and fructose, which have wide applications in food industry especially as sweeteners. Glucose–fructose mixture has much lower crystallinity compared to sucrose and therefore used in the production of noncrystallizing jams and creams. They are also used as liquid sweeteners. Immobilization enables repeated use, provides significant reduction in the operation costs, facilitates easy separation and speeds up recovery of enzyme and extends the stability of enzyme by protecting the active material from deactivation. Industrial application of immobilized invertase may decrease the production cost of glucose–fructose mixture because it could be used repeatedly for long periods. Although invertase is not a very expensive enzyme, the technique can also be applied to expensive ones for biotechnological productions.

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Section: Resultsmentioning

confidence: 60%