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  • Küçük Resim
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    Antimicrobial and antioxidant activity of phenolic extracts from walnut (Juglans regia L.) green husk by using pressure-driven membrane process
    (Springer India, 2023) Arslan, Hüdaverdi; Koç, Eda Öndül; Özay, Yasin; Canlı, Oltan; Özdemir, Sadin; Tollu, Gülşah
    In this study, antioxidant (DPPH and metal chelating), DNA cleavage, biofilm, and antimicrobial properties of extracted phenol from the walnut green husk (WGH) and its different concentrate and permeate samples were evaluated. For maximum phenolic compound extraction from the WGH first, the effects of solvent type (deionized water, methanol, n-hexane, acetone, and ethanol), solvent temperature (25-75 degrees C), and extraction time (0.5-24 h) were optimized. Then to concentrate phenolic compounds a pressure-driven membrane process was used with four different membrane types. The phenol contents of the concentrate samples were found to be microfiltration (MF) concentrate 4400 mg/L, ultrafiltration (UF) concentrate 4175 mg/L, nanofiltration (NF) concentrate 8155 mg/L, and reverse osmosis (RO) concentrate 8100 mg/L. LC-MSMS was used to determine the quantification of phenolic compounds in permeate and concentrate streams. In addition, all of the concentrate samples with high phenol content showed a high antioxidant activity as 100% with MF concentrate, UF concentrate, NF concentrated and RO concentrated. Likewise, concentrate samples were found to have very high antibiofilm activity as 82.86% for NF concentrate againts S. aureus, 85.80% for NF concentrate against P. aureginosa, 80.95% for RO concentrate against S. aureus, and 83.61% for RO-concentrate against P. aureginosa. When the antimicrobial activity of the extracted phenol from WGH and its different concentrate and permeate samples were evaluated by micro dilution and disk diffusion methods, it was found that the ability of the concentrate samples to inhibit bacterial growth was much higher than permeate ones. In addition, extracted phenol from WGH and its different concentrate and permeate samples showed significant DNA nuclease activity.
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    Immobilization of alpha-amylase onto Ni2+ attached carbon felt: Investigation of kinetic parameters from potato wastewater
    (Wiley-V C H Verlag Gmbh, 2023) Acet, Ömür; İnanan, Tülden; Koç, Eda Öndül; Sert, Buse; Acet, Burcu Önal; Odabaşı, Mehmet
    Alpha-amylase is an important enzyme for textile, food, paper, and the pharmaceutical industrial areas. In this study, Ni2+ attached carbon felt structures with nitrogen active site (Ni2+-N-ACF) are produced. The surface morphologies of the N-ACF and Ni2+-N-ACF are investigated by means of scanning electron microscopy (SEM) analysis. Ni2+ ions binding on the N-ACFs are determined by energy dispersive X-ray (EDX) analysis and a graphite furnace atomic absorption spectrometer (AAS). The effect of pH, ionic strength, initial alpha-amylase concentration, and temperature parameters is investigated for alpha-amylase immobilization on Ni2+-N-ACF structures. In addition, pH and temperature effect on the activities of the free and the immobilized amylase, kinetic parameters, storage, and operational stabilities are made. Lastly, starch degradation in potato waste water is tested on Ni2+-N-ACF. The obtained results show that alpha-amylase immobilized Ni2+-N-ACF can be used for starch degradation on an industrial scale.
  • Küçük Resim Yok
    Öğe
    Investigation of Complexing Properties with Polyethyleneimine of Some Commercial Lipases
    (2024) Koç, Eda Öndül; Yilmaz, Mert
    Lipases are enzymes used in various industrial process and are immobilized to increase their applicability as biocatalysts. Ionic polymers such as polyethyleneimine (PEI) make possible the co-precipitation of enzymes. In this study, complexation and aggregation with PEI of enzymes were investigated with commercial enzymes from Novozyme 51032 (Fusarium solani pisi), Palatase 20000 L (Rhizomucor miehei), Lipolase 100 L (Thermomyces lanuginosus), Lipozyme CAL B L (Candida antarctica B) and Amano (Pseudomonas fluorescens) using PEI as a linker and aggregation agent. The highest percentage of PEI-enzyme agregate was obtained for Novozyme 51032, Palatase 20000 L and Lipolase 100 L at the PEI/enzyme ratio of a 1/20-1/80 range. This study documented that Lipozyme CAL B L and (Amano) P. fluorescens enzyme preparations failed to occur precipitates resulting PEI-enzyme aggregates. The some commercial lipase preparations may contain various impurity components that prevent complexation or aggregation with PEI. Complexing with PEI of lipases is based on of basis electrostatic interaction of enzyme with PEI as a cationic polymer resulting in PEI-lipase aggregates.