A novel bacterium, strain ND12, was newly isolated from the tobacco plantation soil and identified as Acinetobacter sp. ND12 based on morphology, physiological tests, 16S rRNA sequence and phylogenetic analysis. The isolate could utilize nicotine as the sole source of carbon and nitrogen. 1.0 g/L nicotine was degraded by Acinetobacter sp. ND12 within 14 h at 28 °C and pH 6.0. The optimum nicotine concentration for the growth of strain ND12 was 2.5 g/L. The resting cells of Acinetobacter sp. ND12 could decompose 90% nicotine in upper tobacco leaves after treating for 11 h. These results suggested that the strain ND12 may be useful for reducing the nicotine concentration in tobacco leaves and nicotine-polluted environments.ITAL