中文摘要：

为解决我国一些烟区烤烟烟碱含量偏高问题，筛选了具有降解烟叶烟碱含量应用潜力的细菌。以烟碱为唯一的碳氯源，从云南省弥勒县的烟草栽培土壤中分离得到1株烟碱降解细菌5—28。经形态学观察和生理生化性质分析，结合16SrRNA测序和系统进化分析将该细菌鉴定为根瘤菌（SinorhiZObiumsp．）5．28。该菌能耐受2．5g／L的烟碱，对烟碱的最适降解条件为：烟碱浓度1．5g／L，pH4．0，温度25℃。经过24h培养，菌株5．28对初始浓度为1g／L的烟碱降解率接近80％，同时，该菌的休止细胞也能有效降解烟叶中的烟碱．

英文摘要：

In order to solve the problem of higher nicotine content in flue-cured tobacco leaves produced in some areas, bacterium strain 5-28, which had the potential of degrading nicotine was isolated from tobacco growing soil in Mile, Yunnan using nicotine as the sole source of carbon and nitrogen. The strain 5-28 was identified as Sinorhizobium sp. 5-28 via morphological observation, physio-biochemical property analysis, 16S rRNA sequencing and phylogenetic analysis. The strain 5-28 is tolerant to nicotine at a concentration of 0-2.5 g/L. The optimum condition for nicotine degradation is： nicotine concentration 1.5 g/L, pH 4.0 and 25 ℃. Almost 80% nicotine would be degraded after cultivation for 24 hours where the initial concentration was I g/L, moreover, the resting cells of strain 5-28 would effectively degrade the nicotine in tobacco leaf as well.