抄録
Gluconobacter suboxydans was cultivated in a fed-batch culture with a DO-stat under the condition that none of the components in the basal medium limited the growth of the microorganism and the production of sorbose. Final concentration of sorbose reached 460 g/l after 16 hrs with CSL medium and 628 g/l after 14 hrs with YE medium, respectively. Conversion ratio of sorbitol to sorbose was almost maintained at about 0.9 for CSL medium and about 1.0 for YE medium during the cultivation. The effect of sorbose concentration on growth was investigated in test tube culture. Decrease in specific growth rate and a lag phase were observed with increase in sorbose concentration in culture medium. The growth was inhibited considerably at 300 g/l of sorbose concentration and was not observed at sorbose concentrations over 510 g/l. The effect of osmotic pressure and water activity on growth was examined. Growth rate and sorbose production rate decreased as osmotic pressure increased or water activity decreased due to the accumulation of sorbose.
