一株弯曲假单胞菌N1的尼古丁降解机制研究

Nicotine, a main alkaloid in tobacco, is an environmental toxicant. Because of its harmful effects, nicotine has been included in Toxic Release Inventory (TRI) database by the United States Environmental Protection Agency (EPA) since 1994. Therefore, it is of great significance for human health to effectively control the content of nicotine in cigarettes and remove nicotine from tobacco wastes in the environment. Various microorganisms can efficiently degrade nicotine as carbon and nitrogen source. The applicant has isolated a nicotine degrading bacterium, idenfiried and called Pseudomonas geniculata N1. It can use nicotine as the sole carbon and nitrogen source and efficiently degrade nicotine. Based on whole genome sequencing and preliminary analysis of metabolic pathway, we found that the strain is quite different from the research results of reported Pseudomonas strains in degradation pathway and metabolic genes. In this project, using strain N1 as the research object, we plan to identify degradation metabolites of nicotine and propose the novel complete metabolic pathway. With the combination of comparative genomics and genetic techniques, we will identify the key genes in nicotine degradation, express the genes, and biochemically study the recombinant proteins. Through the analysis of genomic island, we will reveal the diversity of nicotine degradation in Pseudomonas and elucidate the molecular mechanism. Research on the mechanism of nicotine degradation can provide further insights for utilization of tobacco wastes, bioremediation, and biotransformation of nicotine.

尼古丁是烟草的主要生物碱，是一种环境毒物，1994年，美国环保总局将尼古丁定义为"毒物排放目录"。因此，有效地控制卷烟中的尼古丁含量和从烟草废弃物中去除尼古丁，对于人类健康有着重要意义。有些微生物可以尼古丁作为唯一碳氮源和能源，可有效代谢降解尼古丁。申请人已筛选获得一株以尼古丁为唯一碳氮源生长的高效降解菌-弯曲假单胞菌N1，通过对该菌株进行全基因组测序和代谢途径初步分析，发现该菌株降解途径和代谢基因与恶臭假单胞菌S16不同。本申请项目拟以该菌株为研究对象，鉴定尼古丁的代谢产物，绘制代谢途径；并结合比较基因组学和分子克隆技术克隆尼古丁代谢关键基因，异源表达基因，研究重组蛋白生化性质，通过基因组岛分析，揭示假单胞菌代谢尼古丁多样性和基因来源，最终阐明其尼古丁分解代谢的分子机理。该研究可为烟草废物资源化利用、生物修复被烟草废弃物污染的环境及尼古丁生物转化高值化合物提供重要理论依据。

尼古丁是烟草的主要生物碱，是一种环境毒物，1994 年，美国环保总局将尼古丁定义为"毒物排放目录"。因此，有效地控制卷烟中的尼古丁含量和从烟草废弃物中去除尼古丁，对于人类健康有着重要意义。有些微生物可以尼古丁作为唯一碳氮源和能源，可有效代谢降解尼古丁。申请人已筛选获得一株以尼古丁为唯一碳氮源生长的高效降解菌-弯曲假单胞菌 N1，通过对该菌株进行全基因组测序和代谢途径初步分析，发现该菌株降解途径和代谢基因与恶臭假单胞菌 S16 不同。本申请项目拟以该菌株为研究对象，鉴定尼古丁的代谢产物，绘制代谢途径；并结合比较基因组学和分子克隆技术克隆尼古丁代谢关键基因，异源表达基因，研究重组蛋白生化性质，通过基因组岛分析，揭示假单胞菌代谢尼古丁多样性和基因来源，最终阐明其尼古丁分解代谢的分子机理。该研究可为烟草废物资源化利用、生物修复被烟草废弃物污染的环境及尼古丁生物转化高值化合物提供重要理论依据。