Abstract
Bacteria accounted for the majority of microorganisms on both artificially fermented and non-fermented tobacco leaves. Fermentation decreased the number of species present as well as the total number of microorganisms present on leaves of flue-cured tobacco compared to control leaves. After eight days of fermentation, populations of bacteria, actinomycetes, and fungi were reduced by 52.8%, 9.4%, 79.8%, respectively, and total microorganism counts were reduced 55.7% relative to non-fermented controls. After 18 days, counts of bacteria, actinomycetes, fungi, were reduced 37.0%, 100%, 68.5%, and total microorganism counts were 42.1% below non-fermented leaves. In contrast, the activities of the enzymes peroxidase, polyphenol oxidase, proteinase, and α-amylase increased significantly during fermentation. On day eight, activities of these enzymes increased 197%, 31%, 232% and 164%, respectively, compared with non-fermented control leaves. At the end of the artificial fermentation, enzyme activities were 27 to116% higher than those observed in the control leaves. At the end of the fermentation process, reducing sugar, total nitrogen, and nicotine concentrations in fermented leaves were 9.04%, 5.21%, and 10.18% lower than concentrations in control leaves. Microorganisms, primarily bacteria, were responsible for most biological activities in tobacco leaves during fermentation. It is postulated that microbial enzymes were involved in some of the chemical changes observed during the imposed artificial fermentation of flue-cured tobacco.