Abstract

A bacterium strain ND12, was isolated from the tobacco plantation soil and identified asAcinetobacter sp. based on its morphology, physiology, and 16S rRNA gene sequence. The isolate could utilize nicotine as the sole source of carbon and nitrogen, and completely degrade 1.0 g/L nicotine 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. Strain ND12 grew at a broader pH range than other reported nicotine-degrading bacteria and showed higher nicotine-degrading activity than those bacteria at acidic environment (pH 4.0). The resting cells ofAcinetobacter sp. ND12 could decompose 90% of the nicotine in upper tobacco leaves after treating for 11 h. Moreover, the nicotine metabolites of strain ND12 were analyzed byhigh performance liquid chromatography (HPLC) and compared with Arthrobacter sp. HJ2-3 and Pseudomonas sp. Nic22. Our results suggested that strain ND12 could be useful for reducing nicotine concentration in nicotine-polluted environments and tobacco wastes.

Key words: Nicotine, biodegradation, Acinetobacter sp. ND12, resting cells, tobacco leaves.