【摘要】 为了解决烟草上部烟叶中烟碱含量偏高的行业问题以及应对烟碱污染的环境治理,从福建三明烟区的烟草植株中筛选得到1株具有高效降烟碱特性的内生菌Y5,对其生长、降烟碱特性以及代谢途径进行研究。结果表明:该菌株能够以烟碱为唯一碳源、氮源。经菌株形态和16S rDNA序列分析,菌株属于假单胞菌属（Pseudomonas sp.）。利用Slogistic模型对菌株生长情况拟合得到菌株Y5的生长延迟期为7.5h,最大比生长速率μ_max为0.0396 h^-1。烟碱浓度为0.5～2.0g·L^-1时菌株生长良好;pH为5.0～8.0时菌株具有较高的降解活性;接种量对菌株最终的降解率无显著影响。该菌株在烟碱浓度为0.5g·L^-1的无机盐培养基中,15 h内能够基本完全降解烟碱。菌株Y5降解烟碱的中间产物主要为尼古提林、脱甲基尼古丁、可铁宁、3-丙酰基吡啶和5-pyridin-3-yloxolan-2-one等物质,与已报道的假单胞菌属的吡咯烷途径不同。更多还原

【Abstract】 In order to solve the industrial problem of excessive nicotine content in the upper tobacco leaves and to deal with the environmental pollution caused by nicotine, a high efficiency nicotine-degrading endophyte Y5 was isolated from tobacco plants in Sanming Tobacco Area of Fujian, and its growth, nicotine degradation characteristics and metabolic pathway were studied. The results showed that the strain could utilize nicotine as the sole carbon source and nitrogen source. The strain was identified as Pseudomonas sp. by strain morphology and 16 S rDNA sequence analysis. The lag phase of strain Y5 was 7.5 h, and the maximum specific growth rate μ_max was 0.0396 h^-1 by using the logistic model to fit the growth of the strain. Strain Y5 could grow well at concetration of 0.5-2.0 g·L^-1, the degradation activity were high under pH 5.0-8.0. Inoculum amount has no signifidcant effect on final degradation. In an inorganic salt medium with a nicotine concentration of 0.5 g·L^-1, nicotine could be basically completely degraded by strain Y5 within15 hours. The intermediate products of nicotine degradation by strain Y5 were mainly nicotyrine, nornicotine, cotinine, 1-pyridin-3-ylpropan-1-one, 5-pyridin-3-yloxolan-2-one and so on, which were different from the reported pyrrolidine pathway of Pseudomonas.更多还原