Yazar "Temocin, Zuelfikar" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Öğe
    Immobilization of a- amylase on reactive modified fiber and its application for continuous starch hydrolysis in a packed bed bioreactor
    (Wiley-V C H Verlag Gmbh, 2014) Temocin, Zuelfikar
    In this study, the enzyme -amylase was immobilized on reactive modified poly (ethylene terephthalate) fiber. The activities of free -amylase and immobilized -amylase were compared in a batch starch hydrolysis system. Optimum pH and Michaelis-Menten constants were determined for both free -amylase and immobilized -amylase. The immobilization shifted the optimum pH to a higher level. The Michaelis-Menten constant values (K-m) of the immobilized -amylase and free -amylase were obtained as 11.94 and 6.61mg/mL, respectively. The experiments indicated that the immobilization increased the thermal stability of the -amylase. The immobilized -amylase, easily separated from the reaction media, could be used effectively for 15 cycles with 65% retention of the initial activity. Moreover, the immobilized -amylase was effectively used in packed bed bioreactor for continuous starch hydrolysis throughout 6.5h without loss of activity. Different starches (e.g., potato and wheat) were hydrolyzed by the immobilized -amylase in continuous process. The results indicate a potential use of this immobilized enzyme system for the construction of packed bed bioreactors to be used in the hydrolysis of the starch.
  • Küçük Resim
    Öğe
    Use of chemically modified poly( ethylene terephthalate)-g-(acryl amide) fibers for α-amylase immobilization
    (European Polymer Federation, 2007) Temocin, Zuelfikar; Yigitoglu, Mustafa
    Acryl amide grafted Poly(ethylene terephthalate) (AAm-g-PET) fiber was used for covalent coupling of alpha-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 alpha-amylase and immobilized alpha-amylase were characterized by determining the activity profile as function of pH, temperature, thermal stability and storage stability. For the immobilized alpha-amylase, operational stability was also determined. The immobilization of alpha-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 degrees 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. alpha-Amylase immobilized on matrix maintained 40% of its original activity after 30 times of repeated use.