对纳豆杆菌进行了10L发酵罐分批发酵试验,研究发酵罐装液量、接种量、搅拌桨转速对纳豆激酶发酵的影响,并采用Logistic方程、Luedking-Piret方程、Luedking-Piret-like方程描述了发酵中菌体生长、纳豆激酶生成、基质消耗特性。在装液量5L、接种量3%、搅拌桨转速400r/min条件下,发酵得到纳豆激酶活力4 476.25IU/mL,分批发酵过程的动力学模型与实验值拟合度较好。

The fermentation process of Bacillus natto was studied in a 10-L batch system.The fermentation conditions including volume of the medium,inoculation quantity and rotation speed.Models were proposed with the Logistic equation for growth,the Luedking-Piret equation for nattokinase production and Luedking-Piret-like equation for substrate consumption.The optimized conditions were as follows: liquid volume 5L/10L,rotation speed 400r/min,3% inoculum.Under these conditions the activity of nattokinase was 4 476.25 urokinase units of each milliliter broth and the model has provided a good description of Bacillus subtilis.