Semibatch production of fructo-oligosaccharides from sucrose by immobilized cells ofAureobasidium pullulans

Aureobasidium pullulans cells with fructosyltransferase activity were immobilized in 2% calcium alginate beads, and the production of fructo-oligosaccharides from sucrose was studied in a stirred tank bioreactor. It was found that cells ofA. pullulans were entrapped evenly on the alginate matrix of 2.2 mm in diameter, and an effectiveness factor of the beads was determined to be 0.3. By comparison with the system of free cells in batch operation, the total amount of fructo-oligosaccharides produced by immobilized cells was similar although the composition of fructo-oligosaccharides was found to be different. In semibatch operation with immobilized cells, reproducible results up to 60 cycles were obtained at 50 °C and this operation resulted in no loss of activity of immobilized cells.