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Öğe Chitin extraction and characterization from Daphnia magna resting eggs(Elsevier Science Bv, 2013) Kaya, Murat; Sargın, İdris; Tozak, Kabil Özcan; Baran, Talat; Erdoğan, Sevil; Sezen, GöksalNew application areas for chitin and its derivatives have been extensively investigated and there is a solid, growing demand for new chitin sources. In this present study, chitin content of Daphnia magna resting egg (18-21%) was determined for the first time. FTIR, elemental analysis, TGA, XRD and SEM studies revealed the structural and thermal properties of extracted alpha-chitin. This study suggests that D. magna resting eggs can be exploited as an attractive alternative chitin source.Öğe Extraction and characterization of alpha-chitin and chitosan from six different aquatic invertebrates(Springer, 2014) Kaya, Murat; Baran, Talat; Menteş, Ayfer; Asaroğlu, Muammer; Sezen, Göksal; Tozak, Kabil ÖzcanChitin and chitosan were extracted from six different aquatic invertebrate species. Species dry weights varied between 5 % and 20 % chitin, and the chitosan productivity of these chitins varied between 66 % and 74 %. Chitin and chitosan structures were characterized by FTIR, TGA, XRD, and SEM. FTIR results showed that the chitins obtained from the organisms were observed in alpha form. Chitin thermal stabilities were in the order Ranatra linearis > Anax imperator > Hydrophilus piceus > Notonecta glauca > Agabus bipustulatus > Asellus aquaticus, and chitosan thermal stabilities in the order N. glauca > A. bipustulatus > A. imperator > R. linearis > H. piceus > A. aquaticus. The crystalline index values of chitins varied between 76.4 % and 90.6 %. Their surface morphology was examined by SEM, revealing nanofibre structures. These six aquatic invertebrate species with characterized chitin and chitosan structures may be used as alternative chitin and chitosan sources for various technological purposes.Öğe Extraction and characterization of chitin and chitosan with antimicrobial and antioxidant activities from cosmopolitan Orthoptera species (Insecta)(Korean Soc Biotechnology & Bioengineering, 2015) Kaya, Murat; Baran, Talat; Aşan Özüsağlam, Meltem; Çakmak, Yavuz Selim; Tozak, Kabil Özcan; Mol, Abbas; Menteş, Ayfer; Sezen, GöksalThis study examined two gregarious Orthoptera species (Calliptamus barbarus and Oedaleus decorus) as potential sources of chitin. The chitin content of the dry weight of C. barbarus was 20.5 +/- 0.7%, and it was 16.5 +/- 0.7% for O. decorus. Furthermore, the yield of chitosan (70 - 75% deacetylation degree) from the grasshopper species was found to be 74 - 76%, which is close to the yield of commercial preparations obtained from the unused parts of crabs and shrimp. The chitin and chitosan obtained in this way were analyzed using FTIR, TGA, XRD and SEM techniques, and the antimicrobial properties of chitosans obtained from C. barbarus and O. decorus against pathogenic microorganisms of humans and fish were investigated using the disc diffusion and microdilution broth methods. The antimicrobial screening procedures indicated that the chitosan showed significant antimicrobial activity against all of the tested pathogenic microorganisms. The MBC or MFC values were determined to be 0.16 - 2.50 mg/mL. The IC50 values for the chitins obtained from C. barbarus and O. decorus were 10.68 +/- 0.27 and 10.91 +/- 0.96 mg/mL, respectively, which were greater than the value for butylated hydroxytoluene (BHT): 0.04 +/- 0.01 mg/mL. These results suggest that these two species, which are currently considered to be pests because of over-breeding, are potentially alternative sources of chitin and chitosan, which are used in the food/feed industry for their antimicrobial and antioxidant properties.Öğe Natural porous and Nano fiber chitin structure from Gammarus Argaeus (Gammaridae Crustacea)(2013) Kaya, Murat; Tozak, Kabil Özcan; Baran, Talat; Sezen, Göksal; Sargın, İdrisChitin and its derivatives are commercially important biopolymers due to their applications in medicine, agriculture, water treatment, cosmetics and various biotechnological areas. Since chitin and its derivatives exhibit different chemical and physical properties depending on the source and isolation method, there is a growing demand for new chitin sources other than crab and shrimp worldwide. In this study Gammarus, a Crustacea, was investigated as a novel chitin source. Gammarus, which belongs to the family Gammaridae Crustacea, lives in the bottom of aquatic ecosystems. More than 200 species are known worldwide. One of these species, G. argaeus was investigated for chitin isolation. The alpha chitin isolated from G. argaeus was characterized by using analysis techniques such as infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). All these analyses confirmed that the isolated chitin from G. argaeus was in the alpha form. Furthermore, we described that dry weight of this species contained 11-12 % chitin. SEM examination of the isolated ?-chitin revealed that it was composed of nanofibrils (15-55 nm) and pores (about 150 nm).Öğe Nevşehir patatesinden (Solanum Tuberosum L.)polifenol oksidaz enziminin afinite kromatografisi ile saflaştırılarak kinetik ve elektroforetik özelliklerinin incelenmesi(Aksaray Üniversitesi Fen Bilimleri Enstitüsü, 2013) Tozak, Kabil Özcan; Erzengin, MahmutBu çalışmada ekonomik öneme sahip olan Nevşehir patatesinden (Solanum Tuberosum L.) PPO enzimi amonyum sülfat çöktürmesi ve diyaliz işlemlerini takiben uygulanan afinite kromatografisi yöntemi ile saflaştırılarak karakterize edilmiştir. Kullanılan afinite jeli Sepharose-4B-L-tirozin-p-aminobenzoik asit kimyasal yapısına sahiptir. Nevşehir patatesinden PPO enzimi % 15.16 verim ve 52.25 saflaştırma derecesi ile elde edilmiştir. Farklı substratlar için optimum pH ve sıcaklık taraması yapılmıştır. Saflaştırılan enzim L-tirozin ve p-kresol substratlarına karşı hiçbir aktivite göstermezken, katekol, gallik asit ve pirogallol substratlarına karşı oldukça yüksek bir akivite göstermiştir. Bu sonuçlar Nevşehir patatesi PPO enzminin monofenolaz (kresolaz) aktivitesinde yoksun olduğunu ve sadece difenolaz (katekolaz) aktivitesine sahip olduğunu göstermektedir. Optimum pH ve sıcaklık çalışmalarında en yüksek aktiviteyi pH 7 ve 20 0C ' de katekol substratı ile elde edilmiştir. Katekol substratı için KM ve Vmaxdeğerleri sırasıyla, 5 mM ve 5000 U/mLdak olarak bulunmuştur. Altı farklı inhibitör için IC50 ve Ki değerleri tespit edilmiştir. Askorbik asitin enzim üzerinde en güçlü inhibitör etkisi gösterdiği gözlenmiştir.Öğe Purification of polyphenol oxidase from Nevsehir potato (Solanum tuberosum L.) and investigation of its in vitro inhibition by some pesticides(American Chemical Society, 2014) Erzengin, Mahmut; Tozak, Kabil Özcan[Abstract Not Available]
