Stability and Effectiveness of Glucose Biosensor Based on Escherichia coli Using Immobilized Glutaraldehyde

Abstract

The immobilization glucose dehydrogenase (GDH) cells from Escherichia coli cross-linking glutaraldehyde on a carbon paste electrode were studied. Cyclic voltammetry are employed to investigate the catalytic behavior of the biosensor. The analysis used for the optimization of GDH activity was response surface method. Optimum conditions for GDH activity was at temperature 30 oC, pH 6, glucose 10.25 mM, and pyrroloquinoline quinone (PQQ) 3.05μM for E. coli cells without cross-link with glutaraldehyde. On the other hand, the optimum conditions for GDH activity of E. coli cells cross-linked with glutaraldehyde was at temperature 30 oC, pH 6, glucose 10.25 mM, PQQ 3.05 μM, and glutaraldehyde 12.5 μL. Dehydrogenase reaction kinetics of GDH catalyzed by glucose followed the Lineweaver-Burk kinetics. KM app value of bacterial E. coli cells cross-linked with glutaraldehyde at 1.1162 mM was smaller than without cross-link, which was 1.9007 mM. Stability of activity GDH E. coli cells cross-linked with glutaraldehyde was 68% higher than that without cross-link.