本文研究了纳豆菌株ZN-4 (Bacillus natto)的液体深层发酵条件及其对纳豆激酶活力的影响，结果表明：纳豆菌株ZN-4液体深层发酵的最佳培养基配方为：葡萄糖2%，大豆蛋白胨1%，Na2HPO4 0.6%，NaH2PO4 0.1%，MgSO4 0.05%，CaCl2 0.02%；最佳培养基起始pH 7.0，接种量为3%，最适发酵温度为35 ℃。在此条件下，摇瓶、50 L罐和500 L罐发酵酶活最高分别达到1903 U/mL、2210 U/mL和1934 U/mL。

The effect of liquid fermentation on Nattokinase activity produced by Bacillus natto No.ZN-4 strain was studied. Results showed that the optimal culture conditions were 2% glucose, 1% peptone, 0.6% Na2HPO4, 0.1% NaH2PO4, 0.05% MgSO4, 0.02% CaCl2, pH 7.0, the inoculums size 3% and temperature 35 ℃. Under these conditions, the Nattokinase activities of the strain reached 1903 U/mL in shake-flask, 2210 U/mL for 50 L fermentation, and 1934 U/mL for 500 L fermentation, respectively.

广州市科技科技攻关重点项目（2004Z2-E4041）