Abstract: β-glucanase produced by immobilized Escherichia coli JM 109-pLF3 in a packed bed bioreactor was studied. In batch fermentation，the highest enzyme activity of 100.3 U/mL was achieved at a recycling rate of 44.49 mL/min and an aeration rate of 0.6 mL/min after 48 h cultivation. In repeated batch operation，the enzyme activity up to 100 U/mL was obtained in 5 cycles，showing high stability of the immobilized cells. In continuous fermentation，the production of β-glucanase by immobilized cells was kept more or less constant. When the dilution rate was 0.05 h-1，the enzyme activity in the fermentation broth was 39.1 U/mL.