纳豆芽孢杆菌菌剂的制备工艺

采用单因素及正交试验对纳豆芽孢杆菌发酵培养基、pH、温度、发酵时间等条件进行了考察,利用喷雾干燥法制备菌剂,考察了β-环糊精、蔗糖、可溶性淀粉及脱脂奶粉作为保护剂对菌剂制备的影响,并研究了储藏时间及条件对菌剂发酵活力的影响.研究结果表明:纳豆芽孢杆菌发酵培养基为黄豆浸汁培养基:黄豆以5倍水体积浸泡8~14h,121℃~126℃,0.1~0.15MPa处理1h,滤除黄豆,取豆水,加入5%的葡萄糖和0.02%的K2HPO4,调节pH至7.0;最优发酵工艺:初始pH7.0,37℃发酵10h;喷雾干燥最佳保护剂为5%脱脂奶粉;菌剂4℃冷藏180d以内不影响发酵活力.上述工艺下所制得的纳豆芽孢杆菌菌剂活菌数为6.5×108 CFU/g,发酵生产纳豆激酶性能良好.发酵生产纳豆激酶酶活为2 000~2 200IU/g.本研究为纳豆芽孢杆菌菌剂制备提供了一条较为合理的工艺路线.

Preparation process of Bacillus subtilis natto agents

The preparation process of Bacillus subtilis natto agents was studied, which concluded the optimization of fermenting medium, pH, temperature and fermenting time. The agent was prepared by the spray drying method, the influence of different protective agent was studied, and the influence of the storage time and conditions on the fermenting activity of Bacillus subtilis natto agent was also studied. The results showed that, the optimal fermenting medium is soybean extract medium, soybean soaked with 5 times water for 8 ～ 14 h, then hydrolyzed at 121 ℃～126 ℃ and 0.1～0.15 MPa for 1 hour, then filtered,and the filtrate was collected, then 5% glucose and 0.02% K2HPO4 was added to the filtrate, meanwhile,the pH was adjusted to 7.0. The optimal fermenting process are pH 7.0 37 ℃ for 10 hours. The optimal protective agent is 5 % skim milk powder. The optimal storage conditions is within 180 days at 4 ℃. Under this optimal process, the agent is produced with survival bacterium number of 6.5 × 10^8 CFU/g,which could ferment nattokinase with the activity of 2 000～2 200 IU/g. Through this study a reasonable preparation process of Bacillus subtilis natto agents is supplied.