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DEMİR, SERAP

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Author: OKTAY, BURCU × Subject: Enzyme immobilization ×

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    Immobilization of alpha-amylase onto poly(glycidyl methacrylate) grafted electrospun fibers by ATRP
    (ELSEVIER, 2015) OKTAY, BURCU; Oktay, Burcu; Demir, Serap; Kayaman-Apohan, Nilhan
    In this study, novel alpha-amylase immobilized poly(vinyl alcohol) (PVA) nanofibers were prepared. The PVA nanofiber surfaces were functionalized with 2-bromoisobutyryl bromide (BiBBr) and followed by surface initiated atom transfer radical polymerization (SI-ATRP) of glycidyl methacrylate (GMA). The morphology of the poly(glycidyl methacrylate) (PGMA) grafted PVA nanofibers was characterized by scanning electron microscopy (SEM). Also PGMA brushes were confirmed by X-ray photo electron microscopy (XPS). alpha-Amylase was immobilized in a one step process onto the PGMA grafted PVA nanofiber. The characteristic properties of the immobilized and free enzymes were examined. The thermal stability of the enzyme was improved and showed maximum activity at 37 degrees C by immobilization, pH values of the maximum activity of the free and immobilized enzymes were also found at 6.0 and 6.5, respectively. Free enzyme lost its activity completely within 15 days. The immobilized enzyme lost only 23.8% of its activity within 30 days. (C) 2015 Elsevier B.V. All rights reserved.
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    Immobilization of pectinase on polyethyleneimine based support via spontaneous amino-yne click reaction
    (ELSEVIER, 2020) OKTAY, BURCU; Oktay, Burcu; Demir, Serap; Kayaman-Apohan, Nilhan
    The immobilization of an enzyme can improve catalytic activity, stability, and reusability of its. In this study, we investigated a new method for enzyme immobilization. Alkyne-pectinase was first immobilized on the polyethyleneimine-based cryogel via a spontaneous amino-yne click reaction under very mild conditions and then the apple juice was clarified. Amino-yne click reactions do not need any photoinitiator or catalyst, unlike other click reactions. The immobilization efficiency of the alkyne pectinase was 90%. The immobilized enzyme continued to retain 70% of its initial activity after 60 days. An improvement observed in the pH tolerance in the range of 6.5-8.0. The higher thermal tolerance of the immobilized pectinase was increased above 50 degrees C. Immobilized pectinase showed 100% activity at 55 degrees C and pH 6.5. The clarification rate of apple juice was achieved about 50% by the pectinase immobilized support. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.