Degrading starch and cellulose in tobacco leaves by bacteria enzyme agents lsolated from Yuxi tobacco leaf surface | 玉溪醇化烟叶表面细菌酶制剂对烟叶中淀粉和纤维素的降解作用

Chinese. 合理降解烤后烟叶中的淀粉和纤维素含量已成为提高烟叶质量的关键工艺之一。本研究对分离自烤烟叶面的产淀粉酶细菌菌株解淀粉芽孢杆菌(Bacillus amyloliquefaciens A1)和产纤维素酶细菌菌株短小芽孢杆菌(B. pumilus C1)进行发酵培养，提取粗酶液，检测酶活性并应用于初烤烟叶上。通过设计不同酶量、作用时间、相对湿度和温度的方法考察这两种酶制剂对烟叶(Nicotiana tabacum K326)中淀粉和纤维素的降解效果。结果表明，菌株A1主要产α-淀粉酶，酶活力为7×105 U/mL，菌株C1以产内切酶为主，酶活力为6×103 U/mL；在温度40℃、湿度70%条件下作用96 h，用菌株A1所产淀粉酶制剂4×107 U/kg 处理后的烟叶总糖增加率为12.78%，还原糖增加率为12.03%，菌株C1所产纤维素酶制剂4×105 U/kg处理后的烟叶总糖增加率为13.87%，还原糖增加率为18.07%。研究结果提示，利用从烟叶表面分离的产酶菌株进行发酵生产的酶制剂可降解初烤烟叶中淀粉和纤维素，提高还原糖含量，可望在烟叶加工过程中得到应用。

English. Appropriate degradation of starch and cellulose in flue-cured tobacco leaves has become one of the key technologies to improve the quality of tobacco leaves. Bacterial strains Bacillus amyloliquefaciens A1 and B. pumilus C1 isolated from the surface of the tobacco leaves could effectively produce amylase and cellulase respectively. Two strains were cultivated at 37℃ for 60 h and the enzymes were isolated and concentrated from the fermentation metabolites and applied to tobacco(Nicotiana tabacum K326) leaves. Four variables were controlled to detect effects of two enzymes (quantity of enzyme, reaction time, relative humidity and temperature of the investigation). Results illustrated that the strain A1 mainly produced α-amylase which activity was 7×105 U/mL, while strain C1 produced exoglucanase which activity was 6×103 U/mL. In addition, at the temperature of 40℃ and relative humidity of 70% for 96 h, the total sugar and reducing sugar of tobacco leaves treated by 4×107 U/kg amylase from strain A1 increased 12.78% and 12.03%, respectively; as well as treated by 4×105 U/kg cellulase from strain C1 increased 13.87% and 18.07%, respectively. The results suggest that enzyme agents produced by strains isolated from the surface of the tobacco leaves can degrade cellulose and starch in flue-cured tobacco leaves, increase the content of reducing sugar in tobacco processing, and also can apply in the tobacco processing process.