(a) Variations in dextran masses produced with the cell-free enzyme solution (EIBF-batch 1) and by the bacterial cells (MIBF-batch 1 and MIBF-batch 2) with time. The error bar shows a small standard deviation among the triplicate measurements. (b) Variations in sucrose consumed, cell density and sucrose-to-dextran conversion ratio of test MIBF-batch 2. Note that the final sucrose concentration and the enzyme-to-sucrose ratio were 40 g/l and 0·5, respectively. All batches were cultured at room temperature