枯草芽孢杆菌工程菌产中温α-淀粉酶发酵条件优化

Optimization of fermentation conditions for middle-temperature α-amylase production by engineered strain Bacillus subtilis

利用基因工程的手段获得高产中温α-淀粉酶基因工程菌株pWB—amy／WB600，对其在7L发酵罐中的发酵条件进行了研究和优化。结果表明，发酵过程中通过调节通气量和搅拌转速来控制发酵液中的溶氧含量，使溶氧浓度控制为15％-25％；采用流加氨水的方式控制发酵液的pH值为6．0～7．5；并且利用间歇补料的方式，有利于酶量的积累，优化过后的发酵液酶活比未优化时提高了41％。

The fermentation conditions of the engineered strain Bacillus subtilis pWB-amy/WB600, which expresses high-level middle-temperature α- amylase, were investigated and optimized in 7L fermenter. The results showed that the dissolved oxygen concentration was controlled within 15%-25% by regulating aeration and stirring speed. The broth pH was controlled between 6.0 and 7.5 by ammonia feeding. And the fed-hatch fermentation method was adopted to increase enzyme yield. After optimization of fermentation conditions, the enzyme activity was increased about 1.41 times than before.