Karboksillenmiş karbon nano tüplerin partikül boyutunun Aspergillus niger inülinaz enziminin immobilizasyon verimine etkisi
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Tarih
2021
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Siirt Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu tez çalışması, karboksilatlı çok duvarlı karbon nanotüplerin (c-MWCNT) partikül boyutunun Aspergillus niger inulinaz (ANI) enziminin immobilizasyonu üzerindeki etkisini araştırmayı amaçlamıştır. ANI, adsorpsiyon yöntemiyle farklı çaplardaki c-MWCNT'ler üzerinde immobilize edildi. İmmobilizasyon koşulları optimize edilerek 48-78 nm çapa sahip c-MWCNT ile %100 bağlanma verimi ve %89.35 aktivite verimi elde edildi. Serbest ANI (SANI) ve immobilize ANI (IANI), optimum pH, optimum sıcaklık, pH kararlılığı, termal kararlılık ve Michaelis-Menten Sabitleri (Km ve Vmax) belirlenerek karakterize edildi. Optimum pH aralığı (5.5-6.5) ile (3.5-7.5) arasında genişlerken, optimum sıcaklık aralığı (55-65 oC) ile (50-75 oC) arasında genişlemiştir. ANI'nin pH ve termal stabiliteleri, immobilizasyondan sonra arttı. Test edilen tüm pH aralığında ve tüm sıcaklık aralığında IANI'nin SANI'den daha kararlı olduğu gözlemlendi. İmmobilizasyon, enzimin maksimum hızını (Vmax) ve substrat olarak inüline afinitesini azalttı. SANI ve IANI için Vmax değerleri sırasıyla 671.1 µmol/mg.dk ve 602.4 µmol/mg.dk, Km değerleri ise sırasıyla 662.3 g/L ve 689.7 g/L olarak hesaplandı. Km arttıkça enzimlerin substrata olan afinitesi azalır. Hareketsizleştirilmiş enzim, 20 ardışık parti kullanımı için optimum aktivite koşulları altında başlangıç aktivitesini korumuştur. İmmobilize enzim, bir sonraki kullanıma kadar depolama koşullarında (pH'si 6.0 olan 0.1 M sodyum fosfat tampon çözeltisi içinde +4 °C'de saklandı) 30 gün boyunca ilk aktivitesini korudu. Sonuç olarak bu çalışmada elde edilen immobilize enzimin endüstriyel uygulamalarda kullanılabileceği söylenebilir.
This thesis study is aimed to investigate the effect of particule dimension of carboxylated multi-walled carbon nanotubes (c-MWCNT) on the immobilization of Aspergillus niger inulinase (ANI) enzyme. ANI was immobilized on different c-MWCNTs by adsorption method. By optimizing the immobilization conditions, 100% binding yield and 89.35% activity yield were obtained with c-MWCNT that has 48-78 nm diameter. Free ANI (SANI) and immobilized ANI (IANI) were characterized by determining the optimum pH, optimum temperature, pH stability, thermal stability and Michaelis-Menten Constants (Km and Vmax). While the optimum pH range expanded from (5.5-6.5) to (3.5-7.5), the optimum temperature range was expanded from (55-65 oC) to (50-75 oC). The pH and thermal stabilities of ANI were increased after immobilization. It was observed that IANI more stable than SANI at all pH range and all temperature range, tested. Immobilization reduced the enzyme's maximum velocity (Vmax) and affinity for inulin as a substrate. Vmax values for SANI and IANI were calculated as 671.1 ?mol/mg.min and 602.4 ?mol/mg.min, respectively, while Km values were calculated as 662.3 g/L and 689.7 g/L, respectively. When the Km increased, affinity of enzymes for the substrate is decreased. The immobilized enzyme saved its initial activity under optimum activity conditions for 20 consecutive batch uses. The immobilized enzyme maintained its initial activity for 30 days under storage conditions (stored within a 0.1 M sodium phosphate buffer solution which its pH 6.0 at +4 °C in the refrigerator.) until next use. As a result, it can be said that the immobilized enzyme obtained in this study can be used for industrial applications.
This thesis study is aimed to investigate the effect of particule dimension of carboxylated multi-walled carbon nanotubes (c-MWCNT) on the immobilization of Aspergillus niger inulinase (ANI) enzyme. ANI was immobilized on different c-MWCNTs by adsorption method. By optimizing the immobilization conditions, 100% binding yield and 89.35% activity yield were obtained with c-MWCNT that has 48-78 nm diameter. Free ANI (SANI) and immobilized ANI (IANI) were characterized by determining the optimum pH, optimum temperature, pH stability, thermal stability and Michaelis-Menten Constants (Km and Vmax). While the optimum pH range expanded from (5.5-6.5) to (3.5-7.5), the optimum temperature range was expanded from (55-65 oC) to (50-75 oC). The pH and thermal stabilities of ANI were increased after immobilization. It was observed that IANI more stable than SANI at all pH range and all temperature range, tested. Immobilization reduced the enzyme's maximum velocity (Vmax) and affinity for inulin as a substrate. Vmax values for SANI and IANI were calculated as 671.1 ?mol/mg.min and 602.4 ?mol/mg.min, respectively, while Km values were calculated as 662.3 g/L and 689.7 g/L, respectively. When the Km increased, affinity of enzymes for the substrate is decreased. The immobilized enzyme saved its initial activity under optimum activity conditions for 20 consecutive batch uses. The immobilized enzyme maintained its initial activity for 30 days under storage conditions (stored within a 0.1 M sodium phosphate buffer solution which its pH 6.0 at +4 °C in the refrigerator.) until next use. As a result, it can be said that the immobilized enzyme obtained in this study can be used for industrial applications.
Açıklama
Fen Bilimleri Enstitüsü, Gıda Mühendisliği Ana Bilim Dalı
Anahtar Kelimeler
Gıda Mühendisliği, Food Engineering
