Browsing by Author "Aktaş, N."

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Optimization of Aniline Biopolymerization Reaction Conditions by Response Surface Methodology (Rsm)
(Science and Engineering Research Support Society, 2014) Aldemir, A.; Birhanlı, E.; Aktaş, N.; Yeşilada, Ö.
Response Surface Methodology(RSM) was applied to enzymatic polymerization of aniline, which was conducted in a closed system containing sodium acetate buffer and presence of poly(sodium 4-styrene sulfonate) (SPS) polyelectrolyte as a template with laccase enzyme to produce water soluble polyaniline. Laccase enzyme used as catalyst was isolated from Trametes versicolor (ATCC 200801). The enzymatic polymerization rate of aniline based on measurements of initial dissolved oxygen (DO) consumption rate in the closed system, was optimized by the application of RSM. The independent variables, which had been found the most effective variables on the initial DO consumption rate by screening experiments, were determined as monomer concentration, medium temperature and medium pH. A quadratic model was developed through RSM in terms of related independent variables to describe the initial DO consumption rate as the response. Based on statistic analysis, optimum reaction conditions for the maximum initial DO consumption rate determined 42.50 mM, 39.34 °C and 5.45 as monomer concentration, medium temperature and medium pH, respectively. © 2014 SERSC.
Synthesis and Preparation of Responsive Poly(Dimethyl Acrylamide/Gelatin and Pomegranate Extract) as a Novel Food Packaging Material
(Elsevier Ltd, 2020) Alpaslan, D.; Dudu, T.E.; Şahiner, N.; Aktaş, N.
In this study a novel and smart multi-functional hydrogel (MFH) was synthesized from N, N dimethyl acrylamide (DMAAm), gelatin, citric acid (CA) and pomegranate extract (PE) for instant and easy monitoring of the color change in MFH due to changes in medium conditions such as pH and temperature. MFH was utilized as food packaging material, equipped with the developed properties. MFH was synthesized with a redox polymerization technique in film form on petri dishes. Mechanical and water resistance properties of MFH were improved by CA and N, N, methylenebisacrylamide, while PE was used to gain antimicrobial, antioxidant and anthocyanin properties. Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analyzer (TGA), Liquid Chromatography-Mass Spectroscopy (LC-MS/MS) and Scanning Electron Microscopy (SEM) instruments were utilized for characterization of MFH. FTIR revealed the existence of bonding interactions between the functional group of PE and gelatin, carbonyl groups of DMAAm and carboxylic acid groups of CA. TGA results indicate that MFH was stable up to 400 °C. Then the response of total antioxidant and anthocyanin activities leading to the color change in MFH were studied at different pH values. The color change in MFH was monitored even at very small pH changes in the medium. Moreover, antimicrobial activity and stability of MFH were investigated when it was tested in harsh environments and against Escherichia coli, Bacillus subtilis and Staphylococcus aureus on real samples of whole pasteurized milk and cheese for a 7-day period. It exhibited remarkable antimicrobial activity with pasteurized whole milk and cheese. It was concluded that MFH is a very good candidate to be used as biodegradable food packaging material. © 2019 Elsevier B.V.