Isolation, Identification And Degradation Characteristics Of Two Nicotine-Degrading Bacteria

The nicotine-degrading bacterium HZN1 and TW5 were isolated from activated sludge of Hangzhou pesticide factory and identified as Shinella sp. and Pseudomonas sp. based on their physiological characteristics and analysis of 16S rDNA gene, respectively.Strain HZN1 and TW5 are capable of using nicotine as the sole source of carbon, nitrogen and energy, and can growth on the mineral salts medium with nicotine concentration 4.0 g/L. The optimum temperature and pH for strain HZN1 and TW5 growth and nicotine degradation were 30℃and 7.0, respectively. Strain HZN1 could degrade approximately 100% of 0.2, 0.5 1.0 g/L of nicotine within 4, 9, 12 h, respectively; the degradation of nicotine was slightly slower with the presence of glucose; strain HZN1 could degrade nicotine efficiently in a relatively broad range of temperature (23, 30, 37℃) and pH values (5.5 ~ 9.0). Strain TW5 could degrade approximately 100% of 0.2, 0.5 g/L of nicotine within 6, 9 h, respectively; it could only degrade 70% of 1.5 g/L of nicotine at 12 h; temperature and pH have high effects on nicotine degradation by strain TW5.Three intermediate metabolites were produced by the stain HZN1 and identified as cotinine, myosmine and nicotyrine using gas chromatography-mass spectrometry (GC-MS). And possible nicotine-degrading pathway of strain HZN1 was presumed.These results indicate that the strain HZN1 and TW5 could potentially be useful for the remediation of nicotine pollution in mal-condition. This is the first report of nicotine-degrading strain from the genus of Shinella. Our findings would provide a new insight into the biodegradation of nicotine.