کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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70725 | 48843 | 2009 | 7 صفحه PDF | دانلود رایگان |
An industrial enzyme, alkaline serine endopeptidase, was immobilized on surface modified SBA-15 and MCF materials by amide bond formation using carbodiimide as a coupling agent. The specific activities of free enzyme and enzyme immobilized on SBA-15 and MCF were studied using casein (soluble milk protein) as a substrate. The highest activity of free enzyme was obtained at pH 9.5 while this value shifted to pH 10 for SBA-15 and MCF immobilized enzyme. The highest activity of immobilized enzymes was obtained at higher temperature (60 °C) than that of the free enzyme (55 °C). Kinetic parameters, Michaelis–Menten constant (Km) and maximum reaction velocity (Vmax), were calculated as Km = 13.375, 11.956, and 8.698 × 10−4 mg/ml and Vmax = 0.156, 0.163 and 0.17 × 10−3 U/mg for the free enzyme and enzyme immobilized on SBA-15 and MCF, respectively. The reusability of immobilized enzyme showed 80% of the activity retained even after 15 cycles. Large pore sized MCF immobilized enzyme was found to be more promising than the SBA-15 immobilized enzyme due to the availability of larger pores of MCF, which offer facile diffusion of substrate and product molecules.
Journal: Journal of Molecular Catalysis B: Enzymatic - Volume 56, Issue 1, January 2009, Pages 34–40