贝莱斯芽孢杆菌在改善雪茄烟叶品质中的应用

Application of Bacillus velezensis in Improving Quality of Cigar Tobacco Leaves

以CX-014雪茄茄衣晾制结束后的烟叶为材料,对其进行微生物分离纯化,从中筛选出了一株产酶丰富且酶活均处于中高水平的菌株H1,通过形态学和分子生物学方法对该菌株进行了鉴定,并探究了在雪茄烟叶发酵过程中添加外源苯丙氨酸和葡萄糖对该菌株降解烟叶中大分子物质、增加雪茄烟叶香气成分的促进作用。结果表明:H1菌株被鉴定为贝莱斯芽孢杆菌(Bacillus velezensis);在添加外源营养物的条件下经菌株H1发酵后的雪茄烟叶中果胶降解率达到34.93%,淀粉、木质素、蛋白质和纤维素等大分子物质的含量也明显降低;当接菌量为2.4×10^(7) CFU/g,并添加0.25%苯丙氨酸和0.5%葡萄糖的外源物质的情况下,雪茄烟叶在37℃下发酵6 d后,烟叶中新增了异佛尔酮和2,5-十八碳二炔酸甲酯等香气物质,且β-大马酮、2-仲-丁基环戊酮等的含量明显增多,香气得到明显改善。同时,菌株H1的产香发酵成本低,操作工艺简单,可以在工业生产中推广,以提高烟叶品质。

With the cured wrapper of a cigar tobacco CX-014 as material,a strain H1 producing abundant hydrolases of good activities was selectively obtained through microbial isolation and purification.Then the morphologic observation and molecular biology method were used for its identification.Whether it could facilitate the hydrolysis of macromolecules and the formation of aroma substances in cigar tobacco during the fermentation process in the presence of exogenous phenylalanine and glucose was further explored.The identification results showed that strain H1 was Bacillus velezensis.Relying on fermentation by strain H1 along with adding exogenous nutrients,the degradation rate of pectin in cigar leaves reached 34.93%,and the contents of macromolecules such as amylum,lignins,proteins and cellulose also decreased significantly.After 6-day fermentation at 37℃under the conditions of an inoculation amount being 2.4×10^(7) CFU/g and adding 0.25%phenylalanine and 0.5%glucose,some new aromatic substances like isophorone and 2,5-octadecadiynoic acid methyl ester appeared,meanwhile the contents ofβ-damascenone and 2-secbutylcyclopentanone significantly increased,so that the aroma note of the cigar tobaccos was improved markedly.In conclusion,the flavoring fermentation cost of strain H1 is low and the operation process is simple,so it can be popularized in industrial production to improve the quality of tobacco leaves.