Biodegradation of Nicotine and TSNAs by Bacterium sp. Strain J54

Background: Microorganisms play an important role in reducing harmful substances in flue-cured tobacco. Numerous studies have been conducted to degrade nicotine by microorganisms. Objectives: The present research deals with the isolation of a potent bacterial strain able to efficiently degrade nicotine and tobacco-specific nitrosamines (TSNAs) in flue-cured tobacco. Material and Methods: Bacterial strain J54, capable of efficiently degrading nicotine and tobacco-specific nitrosamines (TSNAs), was isolated from tobacco leaves and identified. The strain J54 can use nicotine as the sole carbon and nitrogen source and could effectively degrade nicotine while growing in a nicotine isolation medium (NIM) medium. Results: Compared with the control (CK), the total TSNAs content in the tobacco flue-cured eaves after being sprayed with a solution of the J54 strain was found to decrease by 26.22%. Therein, the degradation rates of 4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N’-nitrosonornicotine (NNN), N’-nitrosoanatabine (NAT), and N′-nitrosoanabasine (NAB) were 24.01%, 26.27%, 28.6%, and 1.83%, respectively. Conclusions: Bacterial strain J54, was isolated from tobacco leaves and identified as a bacterium, which is similar to Bacillus altitudinis based on its morphological and biochemical characteristics and by phylogenetic analysis based on 16S rRNA gene sequences. To our knowledge, this is the first report of the isolation and characterization of a Bacillus sp. strain that can efficiently degrade nicotine and TSNAs. The findings pave the way for the application of new biotechnologies for the degradation of nicotine and TSNAs by microorganisms.