In order to develop new natural tobacco spices, a bacterial strain CB-2 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 its aroma is enhanced qualitatively and quantitatively by the spice.