枯草芽孢杆菌ZH-Zj016产亮氨酸氨肽酶的发酵控制研究

Study on fermentation control study for leucine aminopeptidase production by Bacillus subtilis ZH-Zj016

一种通过原生质体转化技术所获得的可产壳氨酸氨肽酶的枯草芽孢杆菌工程菌ZH—Zj016，在对其发酵条件单因素初步优化的基础上，通过控制最低溶氧、两阶段变温培养、细胞通透性调节等，获得15L自控式发酵罐最适发酵条件：初始pH8．0，装液量8．0L，发酵温度（15h前39％，15h后37％），培养时间28h，接种量7‰（V／V），搅拌转速为250-500r／min，罐压控制在0．06～0．08MPa，通气量1．2vvm，溶氧和搅拌转速相偶联，最低溶氧维持在40％，在此条件下，酶活可达138U／mL，与该菌摇瓶优化条件下相当，是原野生菌15L发酵罐平均水平（6．5u／mL）的21倍。

A leucine aminopeptidase producing strain Bacillus subtilis ZH-Zj016 was obtained by protoplast transformation technology. Fermentation conditions of the strain were firstly optimized through single factor experiments. Then a series of fermentation control strategies,such as the minimum dissolved oxygen control, temperature-shift culture and cell permeability regulation,were performed and the optimal fermentation conditions for 15L fermenter was confirmed as follows：medium volume of 8L,initial pH8.0,7%o of inoculum volume, agitation rate of 250-500r/min pressure at 0.06-0.08MPa, 40% dissolved oxygen （DO） upholding （The DO and agitation rate were coupled）,ventilation volume of 1.2vvm,culture temperature at 39℃; within 15h and shift to 37℃ thereafter. After fermentation for 28h,leucine aminopeptidase activity produced by the strain reached 138U/mL,which was 21 times of the original strain.