烟草中淀粉降解菌的筛选、鉴定及发酵工艺优化

Screening,identification and fermentation process optimization of starch degrading bacteria in tobacco

从河南初烤烟叶表面分离筛选得到一株淀粉降解菌HX-6,并对菌株产酶培养基和烟叶发酵工艺进行优化。结果表明:淀粉降解菌HX-6为枯草芽孢杆菌(Bacillus subtilis),其最佳产酶培养基配方为:可溶性淀粉与红薯淀粉(m可溶性淀粉∶m红薯淀粉=1∶1)17.0 g/L,蛋白胨与酵母粉(m蛋白胨∶m酵母粉=1∶1)21.89 g/L,KNO 32.58 g/L,菌株经最佳产酶培养基培养后,其菌株酶活力提高了71.51%;烟叶发酵最优工艺为:HX-6菌株粗酶液添加量4%、发酵温度35℃、发酵时间27 h,发酵后淀粉降解率达31.75%,总糖和还原糖含量分别增加了18.8%,20.2%,感官品质显著提升(P<0.05),香气质变好,香气量增加。

A starch degrading bacterium HX-6 was isolated and screened from the surface of Henan flue-cured tobacco leaves,and the enzyme-producing medium and tobacco fermentation process of the strain were optimized.The results showed that starch degrading bacterium HX-6 was identified as Bacillus subtilis,and the optimum enzyme-producing medium formula was as follows:17.0 g/L soluble starch and sweet potato starch(m soluble starch∶m sweet potato starch=1∶1),21.89 g/L peptone and yeast powder(m peptone∶m yeast powder=1∶1),2.58 g/L KNO 3.The enzyme activity of HX-6 was increased by 71.51%.The optimum tobacco fermentation process was found to be using 4%crude enzyme solution of HX-6 strain and fermenting at 35℃for 27 h.After fermentation,the starch degradation rate reached 31.75%,and the total sugar and reducing sugar content increased by 18.8%and 20.2%respectively.The sensory quality was significantly improved(P<0.05),and the aroma quality became better,with the increase of aroma volume.