[Identification and primary application of TSNA degrading bacterial strain AS97 isolated from aging tobacco leaves].
OBJECTIVE
The purpose of this work was to screen strains having tobacco-specific nitrosamines (TSNA) deteriorating activity, isolated from the inner and superficial of tobacco plants. Then strain AS97 was isolated and identified for further application.


METHODS
Strain AS97, with the highest conversion ability against both nitrate and nitrite, was screened by enrichment and selective medium. The strain was identified by morphological, physio-biochemical characteristics and 16S rRNA gene sequence analysis. The concentration of 4-(methylnitrosamino)-1-(3-pyridy)-1-butanone (NNK), N-nitrosonicotine (NNN), N-nitrosoanatabine (NAT) and N-nitrosoanabasine (NAB) were determined by LC-MS/MS. The fermentation broth of strain AS97 was spraied on the leaves of tobacco to define inoculum concentration and fermentation condition.


RESULTS
AS97 was identified as Pseudomonas fluorescens (Genbank accession number: JF 449445). Under the optimal growth conditions with inoculum concentration of 5%, at 30 degrees C for 10 d, AS97 had high biological activity against NNK and NNN with a degradation rate of 59.08% and 38.79%, respectively. The correlation analysis displayed a pronounced correlation (p > 0.01) among the concentration of nitrate, nitrite and TSNA. Furthermore, the results also exhibited that nitrate and nitrite were antecedent substance of TSNA.


CONCLUSIONS
These results indicated that Pseudomonas fluorescens AS97 could be a promising microorganism in the practice of non-harmful cigarette production.
College of Plant Protection, Shaanxi Key Laboratory of Molecular Biology for Agriculture, Northwest A&F University, Yangling 712100, China. 21-hy@163.com
Hongying
H
Shan
Dexin
D
Chen
Jing
J
Li
Taichun
T
Chen
Huaixi
H
Hu
Zhigang
Z
Guo
Derong
D
An
D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009602:Nitrosamines / Q000378:metabolism*; D018515:Plant Leaves / Q000382:microbiology; D011551:Pseudomonas fluorescens / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D014026:Nicotiana / Q000254:growth & development / Q000382:microbiology*
D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines