Xylan-based biodegradable and wheat gluten-based antimicrobial film production

Karamanlıoğlu, Mehlika
In the first part of the study, birchwood xylan-lignin film formation was studied. After film forming effect of lignin on pure birchwood xylan was demonstrated, the minimum lignin concentration necessary to form films was determined as 1.1% (lignin/xylan). So, it was determined that keeping about one percent lignin in xylan (w/w) was sufficient for film formation. Biodegradability of the lignin-birchwood xylan composite films was investigated enzymatically using 0.21 U / ml xylanase in an accelerated test. All the films containing lignin were hydrolyzed by xylanase showing biodegradability of the films. Colors of the birchwood xylan-lignin composite films containing different lignin concentrations were compared. Deviations of the color from the reference color were similar between the films. In the second part of the study, photocatalytic antimicrobial film production was investigated on wheat gluten-based films. In order to produce antimicrobial films, wheat gluten films were coated with a semiconductor, titanium dioxide (TiO2), applying different procedures. Coated films were illuminated and photocatalytical inactivation of Escherichia coli on films were determined by antimicrobial tests. The coating procedure in which titanium dioxide (TiO2) was produced from titanium tetraisopropoxide (TTIP) in aqueous-nitric acid and aqueous-hydrochloric acid solutions gave the best antimicrobial result but the films turned out to be deformed and brittle. Spreading TiO2 sol-gel on semi-dried wheat gluten films resulted in flexible and undeformed films having about 40% antimicrobial activity.


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Şaki, Neslihan; Akkaya, Engin Umut; Department of Biochemistry (2004)
This thesis covers the combination of two seperate work accomplished during the throughout the study. In the first part of the study, xanthene based artificial enzymes were synthesized, and kinetic hydrolysis studies done. Artificial enzyme design is an active field of supramolecular chemistry and metalloenzymes are attractive targets in such studies. Enzymatic catalysis is essentially a ءmultifuctional̕ catalysis. As part of our work, we designed and synthesized three novel xanthene derivatives. All three ...
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Çınar, Merve; Bakır, Ufuk; Department of Chemical Engineering (2009)
The aim of this study was to investigate the viability of patterning by immobilization, photocatalytic removal, and re-immobilization steps of the enzyme on photocatalytically active thin films for biosensor fabrication purposes. For this aim, TiO2-SiO2-Au sol-gel colloids were synthesized and deposited on glass substrates as thin films by dip coating. Cysteamine linker was assembled on gold nanoparticles to functionalize thin films with amine groups for immobilization of model enzyme invertase. Effect of i...
Space-charge-limited current analysis in amorphous InSe thin films
Yılmaz, Koray Kamil; Parlak, Mehmet (2004-04-01)
The study of space-charge-limited currents (SCLC) in amorphous InSe thin films is presented. The temperature-dependent current-voltage (J-V) measurements were carried out for TO/a-lnSe/Au sandwich structures in the range of 200-320 K. For all samples, ohmic behavior was observed up to an electric field strength of about 2 x 10(5) V cm(-1). From the temperature dependence of conductivity data, the position of the thermal equilibrium Fermi level E-fo is determined as 250 meV above the valence band E-v. At hig...
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Eker, Zeynep; Karakaş, Gürkan; Department of Micro and Nanotechnology (2009)
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An extracellular - Pepstatin insensitive acid protease produced by Thermoplasma volcanium
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In this study, some parameters for the production and caseinolytic activity of an extracellular thermostable acid protease from a thermoacidophilic archaeon Thermoplasma volcanium were determined. The highest level of growth and enzyme production were detected at pH 3.0 over an incubation period of 192 h at 60 degrees C. The pH optimum for the acid protease activity was 3.0 and the enzyme was fairly stable over a broad pH range (pH 3.0-8.0). The temperature for maximum activity of the enzyme was 55 degrees ...
Citation Formats
M. Karamanlıoğlu, “Xylan-based biodegradable and wheat gluten-based antimicrobial film production,” M.S. - Master of Science, Middle East Technical University, 2008.