基于白洋淀水体特征的异养硝化-好氧反硝化菌脱氮机理及环境互作机制研究

Baiyangdian Lake, as an important eco-security in Xiongan New Area, has profound significance for the development of Xiongan New Area in maintaining healthy and sustainable ecological functions. In the past few years, the nitrogen pollution is very serious, thus deteriorating the water quality. Therefore, how to remove nitrogen from water bodies in an aerobic environment has become a scientific problem to be solved urgently. For the problem of excessive nitrogen in Baiyangdian Lake, in this study, we combines the unique advantages of heterotrophic nitrification-aerobic denitrification (HN-AD) and performs the following investigations: (1) to design technical methods to enrich and domesticate efficient HN-AD bacteria and identify efficient HN-AD bacteria based on the water quality characteristics of Baiyangdian Lake; (2) to investigate the nitrogen removal metabolic processes and mechanism of the different efficient bacteria based on nitrogen balance and high-throughput sequencing analyses, and establish the optimization model of nitrogen removal efficiency for different type efficient bacteria based on response surface method; (3) to investigate the regulation mechanism of different environmental factors (different temperature-dissolved oxygen-organic matter) on metabolic activities, community structure, and population function of the functional bacteria in the nitrogen removal process, and determine the feedback mechanism of microbial community structure and population function to deal with the environmental disturbance, then establish the mechanisms underlying interactions between efficient HN-AD bacteria and environmental factors. Through systematic investigation of the nitrogen removal and environmental interaction mechanisms of efficient HN-AD bacteria, we could provide essential technical support for the “directional-accurate- efficient” nitrogen removal in Baiyangdian Lake.

白洋淀作为雄安新区重要的生态保障，保持健康可持续的生态功能对新区的发展具有深远意义。近年来，白洋淀氮素污染严重，如何在好氧环境下高效去除水体氮素是亟待解决的科学问题。本项目针对白洋淀氮素超标的问题，结合异养硝化-好氧反硝化菌的独特优势主要开展如下研究：(1)基于白洋淀水质特征构建高效异养硝化-好氧反硝化菌株定向富集驯化技术，完成高效脱氮菌株物种信息的表征；(2)通过氮素平衡和高通量分析，探明不同高效菌株的脱氮代谢途径及机理，并基于响应曲面法构建高效菌的脱氮效能优化模型；(3)考察白洋淀不同水体特征时期，环境因素对源水脱氮过程中功能菌群的代谢活性、群落结构及种群功能的调控机制，以及微生物群落结构和种群功能应对环境扰动的反馈机制，进而建立高效菌株与环境因子的互作机制。最终通过对高效菌株脱氮机理以及与环境互作机制的系统研究，为白洋淀水体实现“定向-精准-高效”的氮素削减提供必要的技术支撑。

白洋淀作为雄安新区重要的生态保障，保持健康可持续的生态功能对新区的发展具有深远意义。近年来，白洋淀氮素污染严重，如何在好氧环境下高效去除水体氮素是亟待解决的科学问题。本项目针对白洋淀氮素超标的问题，结合异养硝化-好氧反硝化菌的独特优势主要开展如下研究：(1)白洋淀异养硝化-好氧反硝化菌群演变及驱动机制分析以及高效菌群的筛选。通过napA功能基因对白洋淀异养硝化-好氧反硝化菌群特征进行分析，并通过环境驱动机制的研究明确关键环境因子；结合白洋淀特定水体水质制定定向富集驯化技术，完成了高效异养硝化-好氧反硝化脱氮菌群的筛选；(2)高效菌群的脱氮特性及影响因素研究。通过火山石和聚酯纤维海绵完成高效菌群的固定化，分析不同碳源、碳氮比、温度等因素对高效菌株脱氮效能的影响。固定化系统在C/N为3.5，硝氮浓度分别为8.5mg/L、5.67mg/L和2.83mg/L的条件下24h去除率分别达到了90.86%~99.11%、88.22%~96.91%和85.42%~88.89%，展现出了良好的好氧反硝化能力。(3)白洋淀异养硝化-好氧反硝化菌群与环境互作机制研究。通过网络分析和结构方程模型考察白洋淀天然环境下和反应器中高效菌群的关键物种特征以及环境响应关系。结果发现不仅固定化混合好氧反硝化菌的物种α多样性和生态位均高于游离菌，而且固定化载体中与硝氮和总氮去除相关的物种的种类和丰度最大。