Gluconate and sorbitol could be produced from glucose and fructose by using glucose-fructose oxidoreductase (GFOR) of the permeabilized cells of Zymomonas mobilis. These substrates, however, appeared to be not suitable for the production of relatively cheap products. Thus, our research was focused on the use of sucrose which was major component of natural sugar sources. Hydrolyzation of sucrose by invertase or other sucrose hydrolyzing enzyme was required for this purpose. Our system has three step reaction; inversion step, oxidoreduction step and gluconate formation step. The use of immobilized multienzyme complex(IMC) has many advantages over single enzyme process. One of these is ability of multi-step reaction. But, estabilishment of operational conditions are very difficult in this process. So, we estabilished several operational conditions; activity ratio, pH, temperature etc. Reactions by IMC were accomplished with different reaction mode. In continuous stirred tank reactor operation, the maximum productivity was reached 4.6g/L·h at dilution rate $0.055h^{-1}$. But, stirred type teactor was disadvantageous for low operational stability. In order to increase the operational stability, recycled packed bed reactor(RPBR) system was adopted that did'nt require stirring. In RPBR, the productivity at recirculation rate=1200ml/h and dilution rate =0.053$h^{-1}$ was 5.2g/L·h. The activity of IMC was maintained totally to 200h of operation time.
