Screening Of Beneficial Microorganisms In Tobacco Leaf And Study On The Improvement Of Tobacco Leaf Quality

The quality of tobacco leaves is closely related to the many macromolecular substances it contains.These macromolecular substances mainly include starch,pectin,cellulose,etc.If the content of these macromolecular compounds is too high,they will produce irritating gases and impurities and produce harmful components in tobacco smoke.In the process of growth and development,microorganisms secrete a variety of degrading enzymes through their own metabolic activities.Therefore,microorganisms are inoculated into tobacco leaves.Through the fermentation of microorganisms,macromolecular compounds that are not conducive to tobacco quality can be degraded in tobacco leaves and the quality of tobacco leaves can be improved.In this study,three microbial strains capable of simultaneously degrading large molecular compounds in tobacco leaves were selected and named as yc10,yc8 and fc3,respectively.Among them,yc10 was used as a single strain to ferment tobacco leaves,and yc8 and fc3 were used as a compound strain to ferment tobacco leaves.Microbial growth by inoculation quantity,fermentation time,inoculation quantity,pH and other factors,and then optimize the strains enzyme production conditions,selecting the best enzyme production conditions to develop strain,the strain of fermented liquid evenly spraying on the leaf surface,at 37?,65%RH fermentation under the condition of tobacco,the variation in content of macromolecular compounds in tobacco leaf before and after fermentation.The specific results are as follows:1.A total of 176 strains of bacteria were isolated from tobacco leaves and other samples.9 strains of bacteria were screened based on the species of bacterial degrading substances,and 3 strains were screened based on the enzyme activity for molecular identification.The results showed that yc10,yc8 and fc3 were all Pseudomonas.2.Enzyme production conditions were optimized for the strain,and the optimal enzyme production conditions of single strain.yc10 were as follows:The fermentation time was 36h,the fermentation pH was 7,the fermentation temperature was 37?,the inoculation amount was 6%,the medium loading amount was 80mL/250mL,the shaking machine speed was 200rpm,the pectinase activity,amylase activity,cellulase activity,protease activity,Lignin peroxidase enzyme activity and Manganese peroxidase enzyme activity of strain yc10 after fermentation were 581.04U/mL,7.38U/mL,7.65U/mL,15.82U/mL,34.55U/L and 38.77U/L.Optimal conditions for enzyme production of yc8:fc3 of the composite strain:The fermentation time was 36h,the fermentation pH was 7,the fermentation temperature was 33? the inoculation amount was 6%,inoculation ratio for yc8:fc3=2:1,medium fluid volume is 80mL/250mL,the shaking machine speed was 160rpm,composite after fermentation strains of pectic enzyme activity,amylase activity,cellulose enzyme,proteinase activity,Lignin peroxidase enzyme activity and Manganese peroxidase enzyme activity 488.32 U/mL,12.22 U/mL,3.73 U/mL,28.53 U/mL,47.65 U/L and 38.45 U/L.3.The strains were inoculated into tobacco leaves for solid fermentation.After fermentation with single strain yc10,the starch reduction in A,B,C and D tobacco leaves reached 13.47%,11.72%,12.13%and 13.38%.The decrease of cellulose was 23.49%,19.5%,19.2%and 20.22%.The decrease of lignin was 7.31%,22.7%,8.26%and 30.43%.The decrease of protein was 28.61%,22.34%,32.99%and 32.37%.The reduction of pectin can reach 33.52%,41.11%,16.86%and 42.86%.The increment of total sugar can reach 20.29%,9.84%,19.89%and 11.38%.Compound strain yc8:after fc3 fermentation,the reduced amount of starch in A,B,C and D tobacco leaves could reach 14.42%,12.48%,13.89%and 14.13%.The reduction of cellulose can reach 13.52%,17.25%,18.4%and 15.16%.The decrease of lignin can reach 12.86%,37.94%,15.87%and 37.15%.The decrease of protein was 32.93%,21.2%,10.79%and 31.39%.The reduction of pectin can reach 20.86%,17.09%,7.84%and 22.94%.The increase of total sugar can reach 13.77%,8.22%,26.55%and 12.66%.By analyzing the aroma components of tobacco leaves before and after fermentation,it was found that the content of alcohol,ester,ketone and other aroma components in tobacco leaves increased after microbial action.This study selected from tobacco leaf surface can degrade many kinds of material strain,after applying microorganism to tobacco,tobacco leaf of starch,cellulose,lignin,pectin and protein content of harmful ingredient that influences the quality of tobacco were decreased,and aroma substance content in tobacco leaves,prove the feasibility of microorganisms on the tobacco industry,for microbial provides theory basis for the application in tobacco leaves.