游离氨（FA）对硝化菌活性的抑制机理及其抑制模型构建

Shortcut nitrification-denitrification is a cost-effective technology to achieve nitrogen removal from wastewater. One of the typical properties of high ammonium wastewater is the presence of high level free ammonia (FA). Based on the selective inhibitory effect of FA on the growth or activity of nitrite oxidizing bacteria (NOB) over ammonia oxidizing bacteria (AOB), nitrogen removal via nitrite pathway from high ammonium wastewater could be achieved. However, lacking of further studies on inhibition and kinetics of FA on nitrifying bacterial resulted in little information revealing the real inhibitory mechanisms of FA in reported literatures. In this project, experimental research will be performed in a sequencing batch reactor (SBR) and statistical analysis of data combined with theory analysis of biochemical reaction will be employed, either. Based on the enrichment of AOB and NOB cultures, the growth and energy generation processes of an enriched AOB and NOB cultures will be decoupled by developing a method. Moreover, the inhibitory effects of FA on the anabolic and catabolic processes of the enriched AOB and NOB cultures will be determined through titration and off-gas analysis (TOGA) technology that could provide dynamic information on mechanisms of bacterial metabolism. The inhibitory mechanism of FA on the gene transcriptome and proteome will be further investigated. In addition, according to the maintenance energy theory of microbial community, the kinetic models is expected to be established to assess the inhibitory effect of FA on the anabolic and catabolic processes of the enriched AOB and NOB cultures, respectively. Therefore, the inhibitory mechanism of FA on the metabolism of nitrifying bacteria will be described from the metabolism process, gene molecular level and inhibitory kinetics, which will contribute to lay the microbiological and kinetic foundation for the popularization and application of shortcut nitrification-denitrification technology.

低能耗、高效的短程生物脱氮是可持续污水生物脱氮主流技术。高氨氮废水会产生较高游离氨（FA），基于FA选择性抑制氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）增殖或活性机理，可实现该类废水短程生物脱氮。现有研究缺乏FA对硝化菌抑制机理和动力学方面的深入研究，导致无法揭示抑制机理本质。本项目通过试验研究、数据统计和生化反应理论分析，在富集AOB和NOB菌属基础上，解耦两类菌属的能量产生和生长过程，利用滴定测量-尾气分析（TOGA）技术，研究FA对硝化菌合成代谢和分解代谢过程的抑制影响。在此基础上，基于微生物细胞基因分子水平，进一步考察FA对硝化菌细胞基因转录组和蛋白质组的影响机制，最后，基于细胞维持能理论，构建FA抑制硝化菌活性动力学模型。因此，本课题基于硝化菌新陈代谢过程、细胞基因分子水平和动力学模型三方面揭示FA抑制硝化菌活性机理本质，为短程生物脱氮技术推广应用奠定微生物学和动力学理论基础。

1、项目的背景.短程生物脱氮技术因其具有低能耗、高效的特点，成为未来可持续污水生物脱氮的主流，基于游离氨（FA）对氨氧化菌（AOB）和亚硝酸盐氧化菌（NOB）的选择性抑制机理，可优化硝化菌种群。目前FA对硝化菌新陈代谢过程和细胞基因分子水平层面的抑制机理和抑制动力学方面的研究有待深入，导致无法充分揭示FA抑制硝化菌活性的真正机理。.2、主要研究内容.（1）基于代谢机理和动力学机理的特性差异，实现AOB和NOB菌属富集快速扩增；.（2）基于硝化菌利用无机碳酸盐作为能源和碳源，解耦其能量产生过程和生长过程；.（3）基于解耦硝化菌的能量产生过程和生长过程，开展FA对硝化菌新陈代谢过程的抑制机理研究。.3、重要结果.（1）建立氨氧化菌和亚硝酸盐氧化菌种群快速富集与扩增培养技术；.（2）建立解耦硝化菌能量产生过程和生长过程的方法；.（3）获得基于硝化菌新陈代谢过程的FA抑制活性机理，规范FA抑制浓度阈值；.（4）获得准确、完善的FA抑制硝化菌活性动力学模型，优化生物脱氮工艺的设计和运行，实现污水处理厂低能耗运行。.4、关键数据.（1）FA抑制AOB活性动力学试验.FA作为基质时，采用Monod方程来描述FA对AOB活性的影响。FA对AOB活性影响关系符合Monod方程，FA作为AOB基质时，可采用Monod方程来描述FA对AOB活性的影响，且最大反应速率vmax为0.33gN/gVSS•d，半饱和常数KS为23.2mg/L。.（2）FA抑制NOB活性动力学试验.FA浓度梯度下亚硝酸盐氧化过程Nitrobacter比耗氧速率(SOUR)变化规律，采用非基质抑制动力学模型对试验数据进行拟合。当FA≥7.3 mg/L时，SOUR随着FA浓度升高而降低。尤其当FA浓度高于22.2 mg/L时，SOUR降为0 gN/gVSS/d，最大比耗氧速率(rmax)为0.62 gN/gVSS/d。.5、科学意义等.本项目基于微生物细胞基因分子水平，构建FA抑制硝化菌活性动力学模型，从硝化菌新陈代谢过程、细胞基因分子水平和动力学模型三方面揭示FA抑制硝化菌活性本质机理，为短程生物脱氮技术推广应用奠定微生物学和动力学理论基础。