A new biosensor for specific determination of glucose or fructose using an oxidoreductase of Zymomonas mobilis

Cells of Zymomonas mobilis were permeabilized with toluene in order to utilize the enzymes, glucose-fructose oxidoreductase and gluconolactonase, inside the intact cells. Permeabilized cells were immobilized in a gelatin membrane, and a whole cell enzyme electrode was constructed by fixing the membrane on pH electrode. The biosensor developed was used for specific determination of glucose or fructose by detecting the production rate of hydrogen ion. Optimum conditions for biosensor response were pH 6.2 and temperature of 39 degrees C. The biosensor was highly specific and reproducible, and calibration curves for glucose and fructose were excellent, being linear up to 5 and 50 g/L, respectively.