title: Decreased tobacco-specific nitrosamines by microbial treatment with Bacillus amyloliquefaciens DA9 during the air-curing process of burley tobacco.
abstract: Tobacco specific nitrosamines (TSNA) mainly consisting of N-nitrosonornicotine (NNN), N-nitrosoanatabine (NAT), N-nitrosoanabasine (NAB), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) are a group of toxic components threatening human health. To inhibit TSNA formation in tobacco leaves, a high nitrite reductive strain with low nitrate reduction ability was isolated and applied to tobacco leaves in an attempt to lower the nitrite precursor of TSNA. By morphology, physiology, biochemistry, and 16S rDNA sequence analysis, the strain DA9 was identified as Bacillus amyloliquefaciens. Under the optimized fermentation parameters (glucose 40 g/L, NH4Cl 4 g/L, corn steep liquor 8 g/L, MnSO4 0.01 g/L, KH2PO4 1.0 g/L, MgSO4 0.3 g/L, initial pH 7.0, inoculum age 6 h, inoculum size 3%, temperature 37 °C), the maximum cell dentisity of 1.2 × 10(9) CFU/mL was obtained at 36 h. The DA9 cell suspensions were applied in the air-curing process of the Burley tobacco (Eyan 6) leaves. The treatment by DA9 cells lowered 32% of the nitrite content and 47% of total TSNA content in the tobacco leaves, and the concentrations of the NNN, NNK, and NAT were decreased by 48%, 12%, and 35%, respectively. Collectively, this study provides a promising strain and a novel strategy for decreasing TSNA during the air-curing process.
authors.affiliation: Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, College of Life Sciences, Hubei University , Wuhan 430062, People's Republic of China.
authors.forename: Xuetuan
authors.initials: X
authors.lastname: Wei
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Deng
authors.forename: Dongbo
authors.initials: D
authors.lastname: Cai
authors.forename: Zhixia
authors.initials: Z
authors.lastname: Ji
authors.forename: Changjun
authors.initials: C
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.forename: Jinping
authors.initials: J
authors.lastname: Li
authors.forename: Shouwen
authors.initials: S
authors.lastname: Chen
mesh_terms: D001407:Bacillus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003890:Desiccation; D005511:Food Handling; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000032:analysis / Q000378:metabolism; D009602:Nitrosamines / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity; D018515:Plant Leaves / Q000737:chemistry / Q000382:microbiology; D012988:Soil Microbiology; D014026:Nicotiana / Q000737:chemistry / Q000382:microbiology*
chemical_list: D009566:Nitrates; D009573:Nitrites; D009602:Nitrosamines
keywords: Bacillus amyloliquefaciens; TSNA; air-curing process; microbial treatment; nitrite