Abstract: In order to develop new natural tobacco spices,a bacterial strain CB2 which produces an unique acidic flavor note was isolated from aged burley tobacco leaves.The physiological and biochemical properties of CB-2 were tested.Coffee was fermented with CB-2 liquid,the obtained spice was added into cigarettes and analyzed by gas chromatography-mass spectrometry.The results showed that CB-2 belonged in a Clostridium.In the fermented coffee,acetic,butyric,n-dodecanoic acids,benzyl alcohol,etc.,generated,and the concentrations of valeric,hexanoic,heptanoic,decylic acids,phenylethyl alcohol,etc.,increased,while furan,5-methyl furan aldehyde,palmitic acid,di-n-butyl phthalate,etc.,disappeared,and the contents of styrene,phenyl acetaldehyde,di-isobutyl phthalate and several higher fatty acids reduced obviously.The cigarette smoke's taste become milder,less irritant and less dry and it's aroma is enhanced qualitatively and quantitatively by the spice.