The glucose concentration was controlled around 0.1g/L and the average specific growth rate was 0.06h~(-1). Under the above conditions the plasmid stability reached 86% and penicillin G acylase activity was 23 000U/L.

• h恒速流加葡萄糖至35h；控制流加过程葡萄糖浓度0.；1g/L左右；平均比生长速率为0