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    Dyeing of wool fibres with synthetic dyes and effect of proteolytic enzymes
    (Asian Journal Of Chemistry, 2007) Dogru, Mehmet; Aytekin, Cetin
    In spite of protein and protein fragments (casein, peptone. etc.) are used widespread as a Substrate for the proteolytic enzymes, the substrate prepared from dyes that adsorbed on appropriate material, such as wool and cotton are also used for enzymes activity determination. The object of this work is to develop the substrates which are easily and economically obtainable and also environmental safer, for the frequently used proteolytic enzymes such as subtilisin carlsberg, trypsin, chymotrypsin and protease type XV1 and if it is possible to prepare the specific substrate at least for one of this enzymes. For this aim, wool was dyed with synthetic dyes such as procion yellow, procion red and procion blue. The results indicate that the most appropriate complex was found to be wool-procion yellow and the most unappropriate complex was found to be wool-procion blue complex.
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    In Vitro Antimicrobial and Antioxidant Activity of Ethanol Extract of Three Hypericum and Three Achillea Species From Turkey
    (Taylor & Francis Inc, 2011) Baris, Deniz; Kizil, Murat; Aytekin, Cetin; Kizil, Goksel; Yavuz, Murat; Ceken, Bircan; Ertekin, A. Selcuk
    The present study was conducted to determine the antimicrobial, antifungal and antioxidant activity of the ethanol extract of Hypericum scabrum L (HSm), Hypericum lysimachioides var. lysimachioides (HL), and Hypericum retusum Aucher (HR) and ethanol extracts of Achillea aleppica D.C. subsp. aleppica (AA), Achillea aleppica D.C. subsp. zederbaueri (Hayek) Hub.-Mor (AZ), and Achillea biebersteinii Afan. (AB). The antioxidant properties of extracts were evaluated using different antioxidants tests, including reducing power, free radical scavenging, deoxyribose assay, metal chelating activities and determination of total phenolic compounds. The extracts obtained from Hypericum and Achillea species showed high antioxidant properties. The protective effects of plant extracts were compared with a well known antioxidant, Butilated Hydroxytoluen (BHT) and -tocopherol. Total antioxidant activity of ethanol extracts of plants were also tested by using ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. Antioxidative activities of plant extracts were found to be comparable with Vitamin E. The results showed that the ethanol extracts of all tested plant exhibited different activity against tested microorganisms. Since most of the studied extracts have good antimicrobial and antioxidant activity, it might be possible to use them as natural food additives that act both as antioxidants and as spices.
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    Removal of methylene blue from aqueous solutions onto Bacillus subtilis: determination of kinetic and equilibrium parameters
    (Desalination Publ, 2013) Ayla, Ayseguel; Cavus, Aynur; Bulut, Yasemin; Baysal, Zubeyde; Aytekin, Cetin
    In the present study, Bacillus subtilis, a Gram-positive bacteria, was used in dried biomass form as biosorbent for removal of methylene blue (MB) from aqueous solutions. Batch adsorption tests were performed at different contact times, temperatures, pH, adsorbent doses, and initial dye concentration. The adsorption isotherms are described by means of the Langmuir and Freundlich isotherms. It was found that the Langmuir equation fit better than the Freundlich equation. Maximum biosorption capacity was found to be 169.49, 178.57, and 181.82mgg(-1) at 298, 308, and 318K, respectively. The adsorption kinetics of MB could be described by the pseudo-second-order reaction model. The activation energy of the biosorption (E-a) was determined as 11.30kJmol(-1) at initial concentration of 50mgL(-1). Free energy of adsorption (G degrees), enthalpy (H degrees), and entropy (S degrees) changes were calculated to predict the nature of adsorption. The estimated values for G degrees were -21.22, -22.02, and -23.01kJmol(-1) at 298, 308, and 318K, respectively. The enthalpy changes and entropy of adsorption were 5.47kJmol(-1) and 89.43Jmol(-1), respectively. The experimental data obtained in the present study indicate that B. subtilis is a suitable and inexpensive adsorbent which can be used for dye removal in wastewater treatment processes.
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    Using Ceriporiopsis subvermispora CZ-3 laccase for indigo carmine decolourization and denim bleaching
    (Elsevier Sci Ltd, 2014) Yavuz, Murat; Kaya, Gulsen; Aytekin, Cetin
    In this study, the production of laccase by Ceriporiopsis subvermispora CZ-3 has been studied under semi solid-state conditions using natural waste as solid support materials. Different concentrations of xylidine derivatives were also investigated as inducer affecting laccase production. Melon peel having the lowest C/N ratio in comparison to other supports led to the highest activity levels, reaching maximum values of about 3000 UL-1 for C. subvermispora CZ-3 in the presence of 2,4-xylidine. Laccase produced by this fungus was partially purified by ammonium sulphate precipitation and Sephacryl S-100 HR size exclusion chromatography. Several kinetic parameters of enzyme were also determined with 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) as a substrate. On the other hand, several compounds were investigated with respect to mediator effect for decolourization of indigo carmine and denim bleaching by this enzyme. It was observed that most of the compounds have mediator effect for decolourization of indigo carmine whereas 1-hydroxybenzotriazol is an appropriate compound for indigo dyed denim bleaching. (C) 2013 Elsevier Ltd. All rights reserved.