Aktivitas dan Stabilitas Glukosa Dehidrogenase Escherichia coli yang Diimobilisasi pada Zeolit Cikembar

Abstract

Glucose level in blood can be measured by using a glucose biosensor. Glucose biosensor commonly utilize glucose dehydrogenase (GDH) produced by microbes as the biological sensors. In this study, electrochemical method was used to measure the activity and stability of GDH from Escherichia coli ATCC25922 immobilized on Cikembar’s natural zeolite, in development of glucose biosensor. Natural zeolite as immobilization matrix was found to increase the activity and stability of the GDH. Optimization of immobilized E. coli cell’s GDH activity was carried cut with response surface method experimental design obtaining optimum conditions at 30 °C, pH 7, [glucose] 20.250 mM, [PQQ] 4.0686 μM, and 250 mg zeolite. Maximum GDH activity was obtained at [glucose] 60 mM, following Lineweaver-Burk equation with the value of 8.8289 mM for KM app and 1.2020μA for Imax app. The stability and activity of E. coli cell’s GDH was 60−70% for 24 hours. Base on these results, Cikembar’s natural zeolite can increase the activity and stability of the E. coli cell’s GDH, but the affinity and stability are still low or not maximum