纳豆芽孢杆菌菌种纯化及不同氮源对其产纳豆激酶的影响

Isolation of Bacillus subtilis Natto and Effects of Different Nitrogen Sources on Nattokinase Production

纳豆激酶(nattokinase,NK)是一种由纳豆芽孢杆菌发酵产生的丝氨酸蛋白酶,具有良好的纤溶活性。本研究从wako Nattokinase中分离纯化出高品质的纳豆芽孢杆菌,旨在探究最适宜该菌产纳豆激酶的发酵培养基氮源。研究人员选择了6种氮源对其进行发酵实验,通过连续测定发酵液的菌量、pH和纤溶活性以观察不同氮源对纳豆芽孢杆菌产纳豆激酶的影响。研究结果表明:最优氮源为乳清蛋白,在以此为氮源的培养基中发酵培养120 h后,纳豆激酶的纤溶活性高达1757.79 U/mL。以乳清蛋白发酵培养基对纳豆芽孢杆菌进行发酵,不仅可以得到高活性的纳豆激酶,还可为纳豆激酶应用于食品、保健品领域提供思路。

Nattokinase(NK)is a fibrinolytic serine protease produced by Bacillus subtilis natto.In this study,highproducing Bacillus subtilis natto was isolated from nattokinase,in order to provide this stain with a fermentation condition which is most suitable for the production of wako Nattokinase.Six kinds of nitrogen sources were selected for fermentation experiments.The effects of different nitrogen sources on the production of nattokinase by Bacillus natto were observed by continuous determination of bacterial biomass,p H and fibrinolytic activity.Our results suggested that the optimal nitrogen source was whey protein,in which enzyme activity reached the highest at 1757.79 U/mL after 120 h fermentation.Fermentation of Bacillus subtilis natto by whey protein fermentation medium not only can obtain higher activity nattokinase,but provide ideas for the application of nattokinase in food and health care products.