After immobilizing the cells, the production medium was fed continuously to the immobilized cell reactor at different dilution rates. The dilution rate was altered whenever a steady state was reached in terms of production of eth- anol and use of substrate. After changing the dilution rate, four vol- ume changes were allowed to reach a new steady state before samples were taken from the top of the column. Samples were cen- trifuged at 12,000g for 6 min and supernatants were used for the residual glucose, residual reducing sugar and ethanol analysis.