Browsing by Author "Uygun, M"

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    Metal-chelated cryogels for amyloglucosidase adsorption: application for continuous starch hydrolysis
    Evli, S; Orhan, H; Aktas, PS; Uygun, M; Uygun, DA
    In the present work, a new metal-chelating platform was designed by using IDA as a chelating agent and Cu(II) as an affinity component for amyloglucosidase adsorption. Poly(AAm-GMA) cryogels were used as structural elements, while GMA monomer served reactive epoxy groups for IDA immobilization. Synthesized cryogels were characterized by FTIR, SEM and EDX studies. Pore diameter of the whole polymeric structure was 3-10 Effects of medium pH, temperature, ionic strength along with amyloglucosidase concentration were also investigated for more effective amyloglucosidase adsorption and maximum adsorbed amount of amyloglucosidase was cryogel by the optimum conditions. Reusability profile of the poly(AAm-GMA)-IDA-cryogels was also studied and it was found that the synthesized cryogels could be used repeatedly for many times without any significant decrease on their adsorption capacity. Also continuous hydrolysis of starch by using immobilized form of amyloglucosidase in a column system was studied.
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    Hydrophobic nano-carrier for lysozyme adsorption
    Altunbas, C; Ural, FZ; Uygun, M; Avcibasi, N; Avcibasi, U; Uygun, DA; Akgöl, S
    In this work, poly(HEMA-APH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. Magnetic behaviour was introduced by simple addition of Fe3O4 into the polymerization medium. Characterization of the nanoparticle was carried out by FTIR, ESR, SEM, AFM and EDX analyses. These synthesized magnetic nanoparticles were used for adsorption of lysozyme. For this purpose, adsorption conditions were optimized and maximum lysozyme binding capacity was found to be 278.8 mg g(-1) polymer in pH 7.0 phosphate buffer at 25(a similar to)C. Desorption and reusability properties of the nanoparticles were investigated and lysozyme adsorption efficiency did not change significantly at the end of the 10 successive reuses.
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    Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch
    Uygun, M; Akduman, B; Ergönül, B; Uygun, DA; Akgöl, S; Denizli, A
    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 degrees C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 degrees C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and K-m values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865mg/mL, respectively. V-max of immobilized amyloglucosidase was found to be (0.496 mu mol/min) about four times less than that of free enzyme (2.020 mu mol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54mg/mL at the end of the 5min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase.