枯草芽孢杆菌DF-54的产酶优化及其对烤制晒烟的提质效果研究OA

To reduce the starch content in flue-cured sun-dried tobacco and enhance the indus-trial processability and safety of novel tobacco materials,this study employed response sur-face methodology and orthogonal experimental design to optimize the enzyme-producing cul-ture medium and fermentation conditions for Bacillus subtilis DF-54,a strain that improves the quality of flue-cured sun-dried tobacco.Comparative analyses were conducted on the crude enzyme solutions produced by the strain under both optimized and non-optimized condi-tions,as well as on the routine chemical components and volatile compounds of semi-finished tobacco products fermented with these enzyme solutions versus sterile water.The results demonstrated that the optimal enzyme-producing medium composition for strain DF-54 was:wheat bran 3.50 g/L,soybean meal 20.41 g/L,KCl 4.64 g/L.The optimal fermentation conditions were:inoculum size 2％,agitation speed 200 rpm,and fermentation time 36 h.Compared to the basal medium and initial fermentation conditions,amylase activity increased by 103.9％.After fermentation,tobacco leaves exhibited a 16.45％increase in total sugar content,a 20.76％increase in reducing sugar content,and a starch degradation rate of 17.21％.The contents of key neutral aroma components,including megastigmatrienone,geranylacetone,β-ionone,and solanesone,were significantly elevated.Geranylacetone and dehydrodihydro-β-ionone showed significant positive correlations with amylase,pectinase,xylanase,and cellulase activities,while exhibiting significant negative correlations with neu-tral and alkaline protease activities.These findings provide a theoretical foundation for the industrial application of tobacco-derived microorganisms in enhancing tobacco leaf quality.