Yazar "Yiğitoğlu, Mustafa" seçeneğine göre listele
Listeleniyor 1 - 14 / 14
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe 2,4,6-Trinitrotoluen (TNT)'in Mikrobiyal Degradasyonu ve TNT ile Kirlenmiş Bölgelerin Biyoremediasyonu(2016) Gök, Zehra Gün; İnal, Murat; Yiğitoğlu, Mustafa2,4,6-trinitrotoluen (TNT) yaygın olarak kullanılan patlayıcı bir kimyasaldır. TNT güvenli üretimi ve depolanması, düşük erime noktası, kimyasal ve termal kararlılığı gibi özelliklerinden dolayı her iki dünya savaşında ana patlayıcı madde olarak kullanılmıştır. TNT'nin askeri faaliyetler için imalatı, kullanımı ve imha edilmesi hem toprak hem de yeraltı sularının kirlenmesine neden olmaktadır. TNT'nin yaygın olarak patlayıcı madde olarak kullanılmasına karşın insan dahil birçok organizma üzerinde toksik etkileri vardır ve TNT yapısında bulunan nitro gruplarının simetrik düzeninden dolayı doğada uzun süre bozunmadan kalabilmektedir. TNT'nin hem yer altı sularında hem de toprakta neden olduğu kirliliğin biyolojik yöntemlerle remediasyonu insan sağlığı ve ekosistem açısından oldukça önemlidir. Bir toksik bileşiğin biyolojik olarak muamele edilebilirliği bu bileşiğin biyodegradasyonunun mümkün olmasına bağlıdır. TNT doğada uzun süre bozunmadan kalabilmesine karşın mikrobiyal ataklar karşısında hassastır. Çeşitli aerobik ve anaerobik bakteriler ve mantarlar sentezledikleri nitroredüktaz enzimleri ile TNT ve TNT'nin transformasyon metabolitlerini parçalayabilmektedir. TNT ile kirlenmiş bölgelerin ıslahı için, TNT'yi parçalayabilme yeteneğine sahip mikroorganizmaların kullanıldığı çeşitli biyolojik temelli teknolojiler geliştirilmiştir. Bu çalışmada konuyla ilgili literatür incelenerek TNT'nin mikrobiyal degradasyon mekanizmaları ve TNT degradasyon kapasitesine sahip mikroorganizma türleri belirlenmiştir. Ayrıca, TNT ile kirlenmiş bölgelerin ıslahında kullanılan biyoremediasyon yöntemleri araştırılmış, yöntemlerin uygulanmasına ait çalışmalar ve yöntemlerin uygulamadaki avantaj ve dezavantajları literatür kaynaklarından derlenmiştir.Öğe Adsorption behaviour of copper (II) ion from aqueous solution on poly(4-vinyl pyridine)(2002) Yiğitoğlu, Mustafa; Arslan, Metin; Temoçin, ZülfikarThe adsorption behaviour of poly(4 - vinyl pyridine) towards copper (II) ion in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment lime, pH of the solution and metal ion concentration on the adsorption were investigated. 45 minutes of adsorption time was found sufficient to reach adsorption equilibrum for the copper (II) ion. The optimum pH was found to be 4,5. The adsorption saturation value was reached at 1,27 mmol ions per gram poly(4 - vinyl pyridine) against 3.15 mM copper (II) ions. It was observed that the adsorption isotherm of Cu (II) fits Freundlich - type isotherms.Öğe Adsorption behaviour of copper(II) ion from aqueous solution on 4-vinyl pyridine grafted poly(ethylene terephthalate) fibers(2002) Yiğitoğlu, Mustafa; Arslan, Metin; Şanlı, Oya; Ünal, Halil İbrahimThe adsorption behaviour of 4 vinyl pyridin grafted poly (ethylene terephthalate) fibers was studied towards the copper (II) ions in aqueous solutions by a batch equilibriation technique. The influence of treatment time, temperature, pH of solution, metal ion concentration and percent graft yield on adsorbed amount were investigated. One and half an hour of adsorption time was found sufficient to reach adsorption equilibrium for copper(ll) ions. It was found that the adsorption isotherm of Cu(II) ions fits to Langmuir type isotherms. The highest adsorption capacity was found to be 0.973 m m o I copper(ll) ion per gram adsorbant. The heat of adsorption value was calculated as -9.57 kj mol1. It was found that the reactive fibers are stable and regenerable by acid treatment without losing its activity.Öğe Akrilamid-Krotonik Asit İç İçe Geçmiş Ağ Yapılı Hidroj ellerinin Metilen Mavisinin Adsorpsiyonunda Kullanımı(2017) İnal, Murat; Tunalı, Beste Çağdaş; Yiğitoğlu, MustafaBu çalışmada akrilamid--krotonik asit hidrojelleri metilen mavisi boyasının gideriminde adsorban olarak kullanılmıştır. Boyanın adsorpsiyonuna pH'nın, krotonik asit yüzdesinin, başlangıç boya derişiminin ve tekrar kullanım sayısının etkisi araştırılmıştır. Yalnızca akrilamidle hazırlanan hidrojellerde pH'nm artması ile adsorpsiyonda bir miktar artış görülmüştür. Akrilamid--krotonik asit hidrojellerinde pH 7, ve 10'da adsorpsiyon hemen hemen yakın bulunmuş, buna karşılık pH 8'de belirgin bir azalma gözlenmiştir. Hidrojellerde bulunan krotonik asit yüzdesinin artması ile adsorpsiyon belirgin bir şekilde artmıştır. Ayrıca adsorbsiyon--desorpsiyon çalışmaları sonucu göstermektedir ki, 20 kere tekrar kullanımdan sonra bile hidrojellerin adsorpsiyon kapasitesi hemen hemen hiç azalmamıştır. Sonuçlar akrilamid--krotonik asit hidrojellerin endüstriyel ölçekte tekstil atık sularından boyaların gideriminde adsorban olarak kullanılabilecegini göstermektedirÖğe Effective Degradation of 2,4,6-Trinitrotoluene (TNT) with a Bacterial Consortium Developed from High TNT-degrading Bacteria Isolated from TNT-contaminated Soil(2018) Gök, Zehra Gün; İnal, Murat; Yiğitoğlu, MustafaIn this study, bacterial strains, capable of using TNT as a nitrogen source, were isolated from TNT-contaminated soil samples collected from military region in Kırıkkale, Turkey. We selected three strains that showed the highest TNT degradation capacity and according to 16S rRNA sequence analysis, the strains were identified as Klebsiella pneumoniae (designated SC1 K1, showed 99% homology), Raoultella planticola (designated SC1 K4, showed 99% homology) and Pseudomonas putida (designated SC1 K5, showed 99% homology). These strain were cultured in medium containing 100 mg L-1 TNT, SC1 K1 degraded 90 % of the initial TNT, SC1 K4 degraded 95 % of the initial TNT, and SC1 K5 degraded 84 % of the initial TNT after 24 h of incubation. Then, to remove TNT more efficiently, we constructed a bacterial consortium with these strains. The developed consortium was cultured in medium containing 100 mg L-1 TNT and the consortium removed 97.2 % of the initial TNT after four-hour incubation period. According to HPLC analyses, The consortium transformed TNT to 2-amino-4,6- dinitrotoluene, 4-amino-2,6-dinitrotoluene and an unknown metabolite. The isolates showed high TNT degradation capacity compared to many previous studies and the developed bacterial consortium can be used to remediate the TNT-contaminated environments.Öğe High productivity bioethanol fermentation by immobilized Saccharomyces bayanus onto carboxymethylcellulose-g- poly(N-vinyl-2-pyrrolidone) beads(Taylor & Francis Ltd, 2013) Gökgöz, Murat; Yiğitoğlu, MustafaCrosslinked graft copolymers of CMC with N-vinyl-2-pyrrolidone (N-VP) were prepared in different grafting yields. Saccharomyces bayanus was immobilized in the graft copolymers of carboxymethylcellulose-g-poly(N-vinyl-2-pyrrolidone) (CMC-g-PVP) for ethanol fermentation. The effects of grafting yield, initial glucose concentration, and crosslinker concentration on the yield of ethanol process was investigated. Ethanol production increased when percentage of N-vinyl-2-pyrrolidone in the graft copolymer was increased. The maximum concentration, productivity, and yield of ethanol were 98.78 g L-1, 8.23 g L-1 h(-1) and 0.494 g g(-1), respectively. Reusability of the immobilized yeasts was found that the materials can be used seven times without losing their activity.Öğe Influences of phenolic compounds on citric acid productivity by Aspergillus niger in stirred fermentor(Univ Catolica De Valparaiso, 2010) Çevrimli, Bekir Sıtkı; Kariptaş, Ergin; Yaşar, Ahmet; Yiğitoğlu, MustafaLigninolytic enzymes of the basidiomycetes play a crucial role in the global carbon cycle. The demand for application of ligninolytic enzymes complexes of white-rot fungi in industry and biotechnology is ever increasing due to their use in a variety of processes. Ligninolytic enzymes have potential applications in a large number of fields, including the chemical, fuel, food, agricultural, paper, textile, cosmetic industrial sectors and more. This ligninolytic system of white-rot fungi is also directly involved in the degradation of various xenobiotic compounds and dyes. Their capacities to remove xenobiotic substances and produce polymeric products make them a useful tool for bioremediation purposes. This paper reviews the applications of ligninolytic enzymes of basidiomycetes within different industrial and biotechnological area.Öğe İpek Serisin ve Potansiyel Uygulama Alanları(2019) Gök, Zehra Gün; Yiğitoğlu, Mustafa; Vargel, İbrahimİpek, fibroin (lifli protein) ve serisin (globüler, zamklama proteini) olarak isimlendirilen iki ana proteinden oluşmaktadır. Fibroin tekstil üretiminde ve çeşitli biyomalzeme uygulamalarında kullanılırken, serisin tekstil endüstrisinde bir atık malzeme olarak kabul edilmektedir. Serisin, belirsiz bir yapıya sahip çok bileşenli bir protein olması nedeniyle, fibroinden daha az dikkat çekmiştir, ancak bu proteinin de biyolojik aktiviteye sahip olduğu ve biyouyumlu olduğu yapılan çalışmalarla gösterilmiştir. Serisin değişken amino asit bileşimi ve çeşitli fonksiyonel grupları ile biyomedikal uygulamalar için ilgi çekici biyoaktif özelliklere sahiptir. Antioksidan karakteri, nemlendirme yeteneği ve memeli hücreleri üzerindeki mitojenik etkisi nedeniyle, serisinin hücre kültürü ve doku mühendisliğinde yararlı olduğu son yıllarda yapılan çalışmalarla gösterilmiştir. Ayrıca, keratinositler ve fibroblastlar üzerindeki olumlu etkileri, başta yara bakım malzemeleri olmak üzere deri dokusu onarımı için serisin bazlı biyomalzemelerin gelişmesine yol açmıştır. Ek olarak, serisin, kemik benzeri hidroksiapatit nükleasyonunu indükleme kabiliyeti nedeniyle kemik doku mühendisliği için kullanılma potansiyeline de sahip olduğu gösterilmiştir. Filmler, süngerler ve hidrojeller gibi kararlı ipek serisin biyomalzemeleri, çapraz bağlama veya diğer polimerler ile karıştırılarak hazırlanmaktadır. Serisin aynı zamanda ilaç salımı için de kullanılma potansiyeline sahiptir, çünkü kimyasal reaktivitesi ve pH yanıtı, serisin bazlı nano-mikropartiküllerin, hidrojellerin ve konjuge moleküllerin üretimini kolaylaştırmakta ve ilaçların biyoaktivitesini arttırmaktadır. Bu çalışmada, önemli bir protein olan ipek serisinin özellikleri ve kullanım alanları özetlenmiştir.Öğe Modifiye sodyum aljinata immobilize edilmiş saccharomyces cerevisiae ile kesikli kültürde biyoetanol üretimi(Kırıkkale, 2012) Yiğitoğlu, Mustafa; İnal, Murat…Öğe Removal of cadmium (II) from aqueous solumns using sporopollenin(Parlar Scientific Publications (P S P), 2004) Arslan, Mehmet; Temoçin, Zülfikar; Yiğitoğlu, MustafaSorption of cadmium ion from aqueous solution by sporopollenin, a polymer obtained from Lycopodium clavatum, was investigated. The influences of adsorption time, temperature, pH of solution, and Cd(II) concentration on the adsorbed amount were investigated. 45 minutes of adsorption time was found to be sufficient to reach equilibrium. The adsorption capacity of sporopollenin was found to be 82.3 munol(.)g(-1). The heat of adsorption value was calculated as 15.3 J(.)mol(-1). Influences of HCl, H2SO4, HCl+H2SO4, and EDTA solutions on desorption were investigated.Öğe Studies on Selective Uptake Behavior of Hg(II) and Pb(II) by Functionalized Poly(Ethylene Terephthalate) Fiber with 4-Vinyl Pyridine/2-Hydroxyethylmethacrylate(Springer International Publishing Ag, 2010) Temoçin, Zülfikar; Yiğitoğlu, MustafaThe adsorption behavior of 4-vinyl pyridine and 2-hydroxyethylmethacrylate grafted poly(ethylene terephthalate) fiber toward the Hg(II) and Pb(II) ions in aqueous solutions was studied by a batch equilibration technique. The influence of the treatment time was considered as well as the pH of the solution, the initial metal ions concentration, the graft yield, and the temperature. Such parameters as the adsorption kinetics, the adsorption isotherm, and the desorption time were further studied. Maximum adsorption occurred at pH 3 and pH 6 for Hg(II) and Pb(II), respectively. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for heavy metal ions. The adsorption data is a good fit with Freundlich isotherm. Desorption studies indicated that the maximum percent recovery of Hg(II) and Pb(II) was 93.4% and 76.3%, respectively with 1 M HNO3.Öğe Studies on the activity and stability of immobilized horseradish peroxidase on poly(ethylene terephthalate) grafted acrylamide fiber(Springer, 2009) Temoçin, Zülfikar; Yiğitoğlu, MustafaHaving been activated with glutaraldehyde, modified poly(ethylene terephthalate) grafted acrylamide fiber was used for the immobilization of horseradish peroxidase (HRP). Both the free HRP and the immobilized HRP were characterized by determining the activity profile as a function of pH, temperature, thermal stability, effect of organic solvent and storage stability. The optimum pH values of the enzyme activity were found as 8 and 7 for the free HRP and the immobilized HRP respectively. The temperature profile of the free HRP and the immobilized HRP revealed a similar behaviour, although the immobilized HRP exhibited higher relative activity in the range from 50 to 60 A degrees C. The immobilized HRP showed higher storage stability than the free HRP.Öğe Synthesis, characterization and in vitro release analysis of pluronic F127 copolymer micelles containing quercetin as a hydrophobic drug(Springer Science and Business Media Deutschland GmbH, 2024) İspir, Elif; İnal, Murat; Gün Gök, Zehra; Yiğitoğlu, MustafaThe object of the present study is to develop a new controlled drug release system by loading quercetin into pluronic F127 micelles. For the experimental studies, first of all, the critical micelle concentration (CMC) of the pluronic F127 copolymer was found as 4.5% g/mL at 25 °C, since the micelle-forming surfactants formed micelles at concentrations equal to or higher than the CMC. Afterward, with thin-film hydration method, three micelle groups with different polymer/quercetin ratios were formed. In this procedure, pluronic F127 polymer dissolved in ethanol at 30–40 °C and different amount of quercetin was added to the polymer solution. The polymer-quercetin solutions were evaporated in the evaporator at 40 °C for 2 h to obtain a film. The resulting film was hydrated by adding of ultrapure water and the micelle suspensions were obtained after filtration. According to Malvern Zetasizer measurement and transmission electron microscope (TEM) analysis, quercetin loaded micelles were determined to have particle sizes between 40 and 50 nm. It was determined by fourier-transform infrared spectroscopy (FTIR) analysis that quercetin was physically found into pluronic F127 micelles without any chemical reaction. It was determined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyzes that quercetin was present in amorphous form as a solid solution instead of in crystalline form in the micelles. Thermogravimetric analysis (TGA) analysis showed that loading quercetin into the micelles did not affect the thermal stability of the PF127 copolymer. The drug loading amounts for micelles were found between 1.95% and 3.3% (mg/mg) for different micelles groups and there was not much difference in the percentage of encapsulation efficiency values thought to the groups. In vitro release profiles of quercetin-loaded micelles were investigated in pH 7.4 phosphate buffer solution and at 37 °C. When the release results were examined in general, it was seen that the release rates of all formulations were almost the same after 168 h. The kinetic parameters of the release results of the micelles in different formulations were calculated according to the Peppas equation and it was determined that the quercetin release in each micelle formulation did not comply with Fick’s law, according to the calculated n parameter. Quercetin-loaded polymeric micelles obtained in this study offer advantages due to their easy synthesis methods and slow release profiles and they can used to successfully encapsulation of hydrophobic active ingredients like quercetin. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2023.Öğe Use of chemically modified poly(ethylene terephthalate)-g(acryl amide) fibers for a-amylase immobilization(2007) Temoçin, Zülfikar; Yiğitoğlu, MustafaAcryl amide grafted Poly(ethylene terephthalate) (AAm-g-PET) fiber was used for covalent coupling of a-amylase. The amide groups of Poly(acryl amide) were converted to the amine groups by Hofmann degradation reaction. The amine groups were activated by glutaraldehyde, before coupling of the enzyme. The free ?-amylase and immobilized ?-amylase were characterized by determining the activity profile as function of pM, temperature, thermal stability and storage stability. For the immobilized ?-amylase, operational stability was also determined. The immobilization of ?-amylase on support caused the optimal reaction pH to shift from 5 to 6. The maximum activity of the free and immobilized enzymes occurred at 50 °C. K m for the immobilized system was higher than that for the free enzyme. The activity of the free enzyme ended in 30 days, whereas the activity of the immobilized enzyme lasted for 60 days at storage conditions. ?-Amylase immobilized on matrix maintained 40% of its original activity after 30 times of repeated use.
