Scopus İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395

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  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Investigation of the Free-Radical Polymerization of Vinyl Monomers Using Horseradish Peroxidase (HRP) Nanoflowers
    (Springer, 2025-01-24) Ozaydin, Gulbahar; Mirioglu, Muge; Dadi, Seyma; Ocsoy, Ismail; Gokturk, Ersen
    In this study, we report the production of flower-shaped HRP-Cu2+ hybrid nano biocatalyst (HRP-Cu2+ HNF) from the complexation between horseradish peroxidase (HRP) enzyme and Cu2+ ions, and investigate catalytic activity and stability of the obtained nanoflowers on the polymerization of some vinyl monomers (styrene, methylmethacrylate, acrylamide and N-isopropylacrylamide). Polymerizations of these monomers, except water soluble acrylamide, were accomplished under emulsion conditions using cationic, anionic and non-ionic surfactants in the presence of hydrogen peroxide (H2O2) and 2,4-pentanedione mediator. Optimum polymerizations were achieved under the conditions of non-ionic surfactant (tween 40) used. HRP-Cu2+ HNF mediated polymerizations resulted in very high yields and molecular weights (Mn) of the polymers. Optimum polymerization of styrene with 84% of yield (Mn = 319 kDa) was accomplished at room temperature. However, the highest polymerization yields for acrylamide (96%, Mn = 171 kDa) and N-isopropylacrylamide (85%, Mn = 185 kDa) was achieved at 70 degrees C. Similarly, optimum polymerization of methylmethacrylate was accomplished with 84% of yield (Mn = 190 kDa) at 60 degrees C. While free-HRP loses its catalytic activity at 60 degrees C and above temperatures, HRP-Cu2+ HNF showed very high catalytic activity and stability even at 70 degrees C. Increasing activity and stability of hybrid nanoflowers provide significant advantages for both scientific and industrial applications.
  • Article
    Citation - Scopus: 2
    Investigation of Peroxidase-Like Activity of Flower-Shaped Nanobiocatalyst From Viburnum Opulus L. Extract on the Polymerization Reactions
    (Turkish Chemical Society, 2024-08-30) Kalayci, Berkant; Kaplan, Naime; Mirioglu, Muge; Dadi, Seyma; Öçsoy, Ismail; Göktürk, Ersen
    Here, we report the effects of peroxidase-mimicking activity of flower shaped hybrid nanobiocatalyst obtained from Viburnum-Opulus L. (Gilaburu) extract and Cu2+ ions on the polymerization of phenol and its derivatives (guaiacol and salicylic acid). The obtained nanoflowers exhibited quite high catalytic activity upon the polymerization of phenol and guaiacol. The yields and the number average molecular weights of the obtained polymers were significantly high. Due to solubility issue of salicylic acid in aqueous media, polymerization of salicylic acid resulted in very low yields. Free-horseradish peroxidase (HRP) enzyme is known to be losing its catalytic activity at 60 °C and above temperatures. However, the synthesized nanoflowers exhibited quite high catalytic activity even at 60 °C and above reaction temperatures. This provides notable benefits for reactions needed at high temperatures, and it is very important to use these kinds of nanobiocatalysts for both scientific studies and industrial applications. © 2024 Elsevier B.V., All rights reserved.