耐冷脱氮微生物可有效治理低温季节氮污染废水，同时也会释放温室气体N2O，污染大气。项目申请人前期研究发现耐冷菌Pseudomonas taiwanensis J488能在15℃条件下进行高效生物脱氮作用。然而，该菌转化无机氮与释放N2O的机理仍不清楚。因此，本项目拟通过测定脱氮酶活力、添加硝化与反硝化抑制剂，明确该耐冷菌转化无机氮的关键酶和限速酶；采用N15示踪技术，明确该耐冷菌转化无机氮过程中形成的含氮中间产物种类和释放N2O的关键通路；结合全基因组测序、转录组测序与实时荧光定量PCR技术，揭示该耐冷菌转化无机氮与释放N2O的分子机制；通过综合分析，阐明耐冷菌P. taiwanensis J488高效转化无机氮与释放N2O的机理。本项目的研究结果可理清该耐冷菌的氮转化途径，有助于深入研究提高脱氮效率的同时减缓N2O的释放速率，此外，也为研发新的氮污染废水处理工艺提供设计方案和理论指导。

The hypothermia denitrification bacteria could effectively remove nitrogen from the nitrogen-contaminated wastewater in the low temperature seasons. A preliminary study by the project applicant found that the hypothermia Pseudomonas taiwanensis J488 could effectively perform biological nitrogen conversion. However, the the mechanisms of nitrogen conversion and N2O emission by strain J488 remained unclear. Therefore, this project initially intends to determine that the key enzymes and the rate-limiting enzymes for inorganic nitrogen transformation by measuring the enzyme activities, and adding nitrification and denitrification inhibitors. The N15 tracer technology would be employed to clarify the nitrogen intermediates in inorganic nitrogen transformation process and the key pathways for N2O emission. The technologies of whole-genome sequencing, transcriptome sequencing, and real-time fluorescence quantitative PCR would be used to elucidate the molecular mechanisms of inorganic nitrogen transformation and N2O emission. The mechanisms of high nitrogen conversion and N2O emission by P. taiwanensis J488 could be unraveled through comprehensive analysis. The results of this project could clarify the pathways of nitrogen conversion of the strain J488, help in-depth research to improve nitrogen removal efficiency and lower N2O emission rate. In addition, it also provides some design solutions and theoretical guidance for the development of new nitrogen pollution wastewater treatment processes.