Abstract：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.
