摘要
选用玉米粉、豆饼粉、KH_2PO_4及Na_2HPO_4为基础配方,通过单因素实验对枯草芽孢杆菌发酵产中性蛋白酶的发酵培养基、培养条件、发酵条件进行优化。确定了优化的发酵培养基为:20g·L~(-1)甘油,30g·L~(-1)豆饼粉,2mmol·L~(-1)氯化钙,0.3g·L~(-1 )KH_2PO_4,4g·L~(-1 )Na_2HPO_4;优化的培养条件为:培养温度30℃,接种量5%。调控发酵培养基pH值7.0控制发酵,发酵24h酶活达到7 344U·mL~(-1)。进行流加甘油实验,培养温度30℃,发酵过程控制pH值7.0,调整转速和通风量控制溶氧30%~35%,接种量5%,经过30h发酵,酶活达到10 654U·mL~(-1),较未补料提高了45%。
Using corn flour,soybean cake powder,KH_2PO_4,and Na_2HPO_4as the basic ingredients,we optimized the fermentation medium,culture conditions,and fermentation conditions of Bacillussubtilisfor producing neutral protease by single-factor experiments.The optimum fermentation medium can be determined as follows:the glycerin of 20g·L~(-1),the soybean cake powder of 30g·L~(-1),the CaCl_2of 2mmol·L~(-1),the KH_2PO_4of 0.3g·L~(-1),and the Na_2HPO_4 of 4g·L~(-1).Furthermore,the optimum culture conditions can be determined as follows:the culture temperature of 30℃,the inoculum of 5%.Under above conditions,the neutral protease activity reaches 7 344U·mL~(-1 )when the pH value of fermentation medium is 7.0,and the fermentation time is24h.While the glycerol fed-batch experiment indicates that the neutral protease activity can reach 10 654U·mL~(-1),which has increased by 45%compared to that of the control group without fed-batch,when the pH value of fermentation medium is 7.0,the inoculum is 5%,the fermentation time is 30h,and the dissolved oxygen concentration is 30%~35%through adjusting the speed and air flow.
引文
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