螯合铁对厌氧铁氨氧化脱氮效能及微生物群落的影响

为深入了解厌氧铁氨氧化反应微生物群落组成特征，本实验选取螯合铁对厌氧铁氨氧化脱氮效果进行了研究，并分析了微生物群落结构、功能及共现网络关系.厌氧反应器经过77 d运行，腐殖酸铁组、柠檬酸铁组、乙二胺四乙酸铁钠组和氨三乙酸铁组总氮去除率分别为83.32%、43.67%、55.07%和12.65%，腐殖酸铁是厌氧铁氨氧化更有效的电子受体.反应结束后，腐殖酸铁组中的脱氮菌群Comamonadaceae丰度约为17.57%，柠檬酸铁组中铁还原菌群Clostridium丰度为47.70%，乙二胺四乙酸铁钠组中脱氮菌群Thermomonas丰度为20.11%.微生物功能预测结果表明，铁循环、硫循环和氮循环关系密切，铁代谢和硫代谢对于脱氮有重要作用；在腐殖酸铁组中，铁呼吸和氮循环相关功能强度较其它组高.通过共现网络推测出Tessaracoccus是螯合铁厌氧铁氨氧化体系的关键物种.

Effect of Chelated Iron on Nitrogen Removal Efficiency and Microbial Community Structure in the Anaerobic Ferric Ammonium Oxidation

In order to understand the characteristics and interactions of the microbial community during the anaerobic ferric ammonium oxidation (FEAMMOX) process, this study investigated the effects of various forms of chelated iron on nitrogen removal efficiency and microbial community structure. After 77 days of reactor operation, the removal efficiency of total nitrogen was 83.32% for the ferric humate group, 43.67% for the ferric citrate group, 55.07% for the ferric sodium ethylene diamine tetraacetate group, and 12.65% for the ferric ammonium triacetate group. After the experiment, the abundance of denitrifying bacteria Comamonadaceae in ferric humate group was 17.57%, the abundance of Clostridium in ferric citrate group was 47.70%; and the abundance of denitrifying bacteria Thermomonas in the ferric sodium ethylene diamine tetraacetate group was 20.11%. This indicates that ferric humate is a more effective electron acceptor for the FEAMMOX process. The result of function prediction shows that the iron, sulfur, and nitrogen cycles are all closely related, with iron and sulfur metabolism playing an important role in nitrogen removal. In the humate group, iron respiration and the nitrogen cycle are more strongly correlated than other groups. Co-occurrence network analysis showed that the keystone species in the FEAMMOX process is Tessaracoccus.