Isolation and Degradation Characteristics of an Entophytic Nicotine-degrading Bacterial Strain in Tobacco

In order to understand the nicotine-degrading mechanisms of tobacco endophytes, an endophytic bacterial strain G16 with a high efficiency nicotine-degrading capability was chosen, and its nicotinedegrading characteristics were studied through the methods of nicotine degradation culture and metabolite analysis. The results showed that the strain G16 was identified as Rhizobium sp.G16 and its growth in nicotine medium could be fitted well by the Slogistic model. The growth inhibition concentration of nicotine for strain G16 was 4000 mg/L. The nicotine degradation capability of strain G16 was affected by pH value, inoculation amount of bacterium, and nicotine concentration of broth. Moreover, the results of metabolite analysis by GC-MS showed that the intermediate products of G16 nicotine degradation included nicotyrine, 3-(3,4-dihydro-2H-pyrrol-5-yl) pyridine, nornicotine, cotinine, and so on.