Browsing by Author "Zhumabekova, Altynay"
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Item Immobilization of horseradish peroxidase enzyme onto polymeric microbeads and its usage in dye decolorization(Bursa Uludağ Üniversitesi, 2023-07-04) Zhumabekova, Altynay; Osman, Bilgen; Bursa Uludağ Üniversitesi/Fen Bilimleri Enstitüsü/Kimya Anabilim Dalı.; 0009-0006-4332-8868In this study, horseradish peroxidase (HRP) enzyme was immobilized onto poly(ethylene glycol dimethacrylate-N-methacryloyl-amido-L-tryptophan methyl ester) [PEDMT] microbeads by adsorption method and used in decolorization of Congo red (CR) and Reactive Black 5 (RB5) dyes. The microbeads were characterized by Brunauer–Emmett– Teller (BET) analysis, Fourier Transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX). Immobilization yield, activity yield, and immobilization efficiency were determined and had a value of 84.86 ± 2.06%, 73.78 ± 5.91%, and 86.95 ± 6.92%, respectively. Relative activities of free and immobilized enzymes were compared, and optimum reaction conditions were determined as pH 6.0, 3% H₂O₂ concentration, and temperature of 50 °C for PEDMT-HRP and 40 °C for free HRP. The effect of metal ions and organic solvents, thermal and storage stability of enzymes were estimated. Also, it was possible to reuse PEDMT-HRP for ten cycles with 55% of the remaining activity. The decolorization studies were performed and the effects of pH, microbeads amount and enzyme concentration, H₂O₂ and dye concentration, and contact time were indicated. The best decolorization was obtained at pH 6.0, 25 mg/L dye concentration, 3% H₂O₂ concentration, and 2 h of contact time for both enzymes. PEDMT-HRP preserved 44% of activity after the ten cycles with CR and 17% after the five cycles with RB5. Moreover, decolorization was followed via HPLC analysis. The results revealed that PEDMT-HRP could simultaneously decolorize both dyes with 94% (CR) and 29% (RB) efficiency, but the free enzyme displayed 4.5% decolorization.