芽孢杆菌混合发酵工艺条件的优化

为提高饲料用芽孢杆菌中性蛋白酶的活力,考察了多种芽孢杆菌混菌发酵产蛋白酶的协同作用效果,并在单因素试验的基础上,采用响应面分析的中心组合试验设计对多芽孢杆菌的混合发酵工艺条件进行了优化。通过优化确定了混合发酵体系的最佳发酵条件为培养基最初pH值7.17,装液量50mL/250mL,接种量3%,发酵温度35.4℃,摇床转速200r/min,发酵周期100h。在优化的工艺条件下,芽孢杆菌混合发酵产蛋白酶的活力单位可达到2 986U/mL。

Optimization of fermentation process by mixed Bacillus strains

To increase the neutral protease activity fermented by Bacillus strains, the synergistic effect of multiple kinds of Bacillus strains for preparing neutral protease by mixture-culture fermentation was investigated. On the basis of single factor experiment, the fermentation process by mixed Bacillus strains was optimized through central composite design. After optimization, a proper mixture-culture fermentation process was determined： initial medium pH 7.17, liquid volume 50 ml in 250 ml flask, agitation speed of rotary shaker 200 r/min, inoculum 3%, temperature 35.4℃, fermentation time 100 h. Under these optimized conditions, the active unit of neutral protease produced by Bacillus strains by mixture-culture fermentation reached 2 986 U/ml.