TSNAs降解菌05-5402的筛选及其降解特性研究

为分离筛选能够降解TSNAs的微生物，探讨其降解特性，本研究采用替代底物平板稀释法分离和靶标底物点接法筛选相结合的分离筛选策略，筛选到能够利用NNK为唯一碳源和氮源而生长的细菌05-5402菌株，鉴定为短小芽孢杆菌（Bacillus pumilus）。白肋烟浸提液经05-5402菌株处理后，TSNAs含量降低了22.2%，其中NNK和NAT的含量分别降低了47.4%和55.7%。晾制的烟叶经05-5402菌株处理后，TSNAs降低17.3%，其中，NAB的含量降低了52.2%。发酵过程中的烟丝经05-5402菌株处理，TSNAs含量下降12.2%。05-5402菌株能实现烟草特有亚硝胺的高效定向降解，具有较大的应用潜力。 

Isolation and screen of TSNAs-degrading bacillus 05-5402 and its degradation characteristics

The aim of current study was to isolate and screen TSNAs-degrading microorganism, and study its degradation characteristics. TSNAs-degrading Bacillus isolate 05-5402 was obtained by isolating bacillus using dilution-plate method with nicotine as alternative substrate, and was screened by selective medium containing NNK as sole carbon and nitrogen sources. Isolate 05-5402 was identified as Bacillus pumilus by physio-biochemical characteristics and 16S rRNA gene sequence analysis. Isolate 05-5402 could degrade 22.2% of total TSNAs in the extracts of burley tobacco, and 47.4% of NNK and 55.7% of NAT. Isolate 05-5402 could reduce 17.3% of total TSNAs in tobacco during air-curing period, and 52.2% of NAB. Total TSNAs content of cut tobacco was reduced by 12.2% after fermentation with isolate 05-5402. Isolate 05-5402 can degrade TSNAs efficiently, which has application potential.