高产纳豆激酶的枯草芽孢杆菌优选及发酵工艺条件优化

Screening of nattokinase high-yielded in different Bacillus Subtilis and optimization of fermentation conditions

以黄豆为主料,添加不同辅料,采用不同处理方式,以产酶活力为指标研究三株枯草芽孢杆菌发酵性能,筛选优势菌株进行固态发酵,确定最优工艺条件。结果表明:在三株受试菌种中BS21076发酵性能最优,活菌数及纳豆激酶活力均较高;最优固态发酵条件为:大豆90℃下烘炒5min,破碎度为四瓣,魔芋精粉添加量3%,接种量为8%,37℃下发酵24h;在此条件下,酶活力可达(3582.48±83.13)U/g,较传统发酵NK活力极显著(p<0.01)提高。

This study was based on soybeans as main material,added different auxiliary material and handled with different treatments. Three Bacillus Subtilis fermentation characteristics were compared and the optimal strain was selected with the index of enzyme activity. The optimal process conditions were determined by solid-state fermentation experiments with the optimal strain. The result showed as follows：among three testing strains,BS21076 had the optimal fermentation characteristics,higher viable count and nattokinase activity. The optimal conditions of solid fermentation were baked at 90℃ for 5min,crushed degree four,3% konjac power,the inoculation of 8% and fermented at 37℃ for 24 h. Under these conditions,the enzyme activity reached（3582.48±83.13）U/g,which compared with traditional fermentation NK activity increased significantly（p〈0.01）.