纳豆激酶液体发酵条件的优化

Optimization of Liquid Fermentation Conditions of Nattokinase

利用单因素及正交试验,对纳豆枯草芽孢杆菌(Bacillus subtilis natto)液体发酵生产纳豆激酶(Nattokinase,NK)的培养基组成(碳氮比和离子组成)和培养条件(温度、pH值、发酵时间、接种量和装液量等)对产酶量的影响进行了研究。结果表明,最佳发酵培养基组成及发酵条件分别为:可溶性淀粉2.0%,大豆蛋白胨1.5%,Na2HPO4·12H2O0.4%,KH2PO40.2%,MgSO4·7H2O0.075%,CaCl20.01%,培养温度37℃,pH值7.0,发酵时间24h,转速180r/min,种龄16h,接种量3%,装液量25mL/250mL。在优化发酵条件基础上,进行了5,20L发酵工艺放大的初步研究,在此条件下,摇瓶,5L罐和20L罐发酵酶活最高分别达到915,1086,946IU/mL。

Compositions of cuhure medium and fermentation conditions for improving quantity of nattokinase produeted by Bacillus subitilis natto was investigated by the single factor research and orthogonal test in liquid fermentation. The optimized medium and conditions were as follows： starch soluble 2%, soy peptone 1.5%, Na2HPO4·12H2O 0.4%, KH2PO4 0.2%, MgSO4·7H2O 0.075%, CaCl2 0.01%, 34 ℃, initial pH 7.0, 180 r/min, liquid volume 25 mL/250 mL baffled flask, 3% of 16 h-old inoculum, for 24 h. Under these conditions, the Nattokinase activities of the strain reached 915 IU/mL in shake-flask, 1 086 IU/mL for 5 L fermentation, and 946 IU/mL for 20 L fermentation.