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    An inclusive physicochemical comparison of natural and synthetic chitin films
    (Elsevier, 2018) Kaya, Murat; Salaberria, Asier M.; Mujtaba, Muhammad; Labidi, Jalel; Baran, Talat; Mulercikas, Povilas; Duman, Fatih
    Natural and synthetic chitin films, obtained from the same source were produced and their physicochemical properties were examined comparatively. Firstly, natural chitin film was obtained from elytra of an insect (Oryctes nasicornis L) and purity of the obtained chitin film (degree of acetylation: 79 +/- 2%) was demonstrated by solid state C-13 nuclear magnetic resonance (C-13 NMR). Then, the synthetic film was produced by dissolving of natural chitin film in LiCl-DMAc. The obtained natural and synthetic films were characterized by AFM, TGA, DSC, FTIR, mechanical properties, light transmission and contact angle. The analyses result demonstrated that natural chitin film lost very important properties such as high thermal stability, transparency, nanofibrous nature, tensile strength, Young's modulus and hydrophobicity after transforming the synthetic film. (C) 2017 Elsevier B.V. All rights reserved.
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    Conversion of waste parasitic insect (Hylobius abietis L.) into antioxidative, antimicrobial and biodegradable films
    (Tech Science Press, 2019) Kaya, Murat; Sargın, İdris; Mulercikas, Povilas; Labidi, Jalel; Salaberria, Asier Martinez; Çakmak, Yavuz Selim; Kazlauskaite, Sonata; Erdönmez, Demet; Baublys, Vykintas
    Hylobius abietis is a plant parasitic insect belonging to the order Coleoptera and which causes severe damages to coniferous forests in Northern and Eastern Europe. This current study is aimed to provide a new viewpoint into the waste of this insect by producing chitosan. Dry insect corpses consisted of 27.9% chitin and 86.2% of the chitin was converted into the chitosan. FT-IR spectra analyses confirmed the purity and the deacetylation degree of the produced chitosan (molecular weight of chitosan; 7.3 kDa). This chitosan exhibited antimicrobial activity against 18 bacterial strains. Further, biodegradable chitosan composite films with beta-carotene were produced. Antioxidant activity of chitosan films were found to be higher than chitosan gels; and beta-carotene incorporation further increased the antioxidative properties of the chitosan films. This study demonstrated that the waste of parasitic insect like H. abietis can be evaluated as a source for production of biodegradable and edible chitosan-based films for applications in food coating.
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    Production of magnetically recoverable, thermally stable, bio-based catalyst: Remarkable turnover frequency and reusability in Suzuki coupling reaction
    (Elsevier, 2018) Baran, Talat; Sargın, İdris; Kaya, Murat; Mulercikas, Povilas; Kazlauskaite, Sonata; Menteş, Ayfer
    In any catalysis system, regeneration of the used catalyst is of great importance to reduce the cost of industrial applications. However, recovery of the used catalyst from the reaction medium is a difficult task and this can hinder regeneration process. Magnetic separation has emerged as an effective tool to overcome the recovery problem. Hence, in this study a magnetically recoverable sporopollenin-based Pd catalyst has been designed and used in synthesis of biaryl compounds via Suzuki coupling reaction. The thermally stable catalyst exhibited excellent catalytic behaviour without giving any by-products. It is noteworthy that despite their low product yield of aryl chlorides in coupling reactions, remarkable product yields which are comparable to those of aryl bromides and iodides were recorded for aryl chlorides. With very low catalyst loading (1 x10(-3) mol%), the catalyst gave TOFs values exceeding one million; i.e., 1.237.500 in very short reaction time. Due to its magnetically separable nature, the catalyst could be recovered from the reaction media easily by increasing the reusability of the catalyst. Even in tenth run biphenyl yield dropped from 99 to 93%.
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    Three-dimensional chitin rings from body segments of a pet diplopod species: Characterization and protein interaction studies
    (ELSEVIER SCIENCE BV, 2016) Kaya, Murat; Mulercikas, Povilas; Sargın, İdris; Kazlauskaite, Sonata; Baublys, Vykintas; Akyuz, Bahar; Bulut, Esra; Tubelyte, Vaida
    Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38 cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02 +/- 2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0-8.0, chitin amount: 6-14 mg, contact time: 30-360 min, protein concentration: 0.2-1 mg/mL). The highest BSA adsorption was observed at pH 5.0 at 20 degrees C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials.