Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China.
Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), College of Environment and Ecology, Chongqing University, Chongqing 400045, China; School of Architecture and Civil engineering, Xihua University, Chengdu 610039, China.
Sci Total Environ. 2023 Aug 20;887:164130. doi: 10.1016/j.scitotenv.2023.164130. Epub 2023 May 12.
Simultaneous nitrogen and phosphorus removal (SNPR) biofilm system is an effective wastewater treatment process. However, the understanding on the mechanism of functional microorganisms driving SNPR is still limited, especially the role of complete ammonia oxidation (comammox) Nitrospira and glycogen-accumulating organisms (GAO). In this study, a sequencing batch biofilm reactor (SBBR) performing SNPR was operated for 249 d. Based on the 16S rRNA gene, comammox amoA amplicon sequencing, metagenomics and batch experiment, we found that comammox Nitrospira was the main ammonia-oxidizing microorganisms (AOM) and provided nitrite for anaerobic ammonia oxidation (anammox) bacteria (AnAOB). Besides, GAO was dominated by the bacteria of genus Defluviicoccus and played a primary role in reducing nitrate rather than nitrite. Fluorescent in situ hybridization (FISH) analysis confirmed that Nitrospira was enriched in the inner layer of the biofilm. Thus, we put forward a novel insight into the mechanism of SNPR biofilm system. Comammox Nitrospira was responsible for nitrite and nitrate production in the inner biofilm, and AnAOB consumed the produced nitrite during the anammox process. While GAO reduced nitrate to nitrite and polyphosphate-accumulating organisms (PAO) converted nitrite to dinitrogen via denitrifying phosphorus removal in the outer biofilm. These findings provide a new understanding in SNPR biofilm system.
同步脱氮除磷（SNPR）生物膜系统是一种有效的废水处理工艺。然而，对于功能微生物驱动 SNPR 的机制的理解仍然有限，特别是完全氨氧化（comammox）Nitrospira 和糖原积累菌（GAO）的作用。在这项研究中，运行了一个进行 SNPR 的序批式生物膜反应器（SBBR）249 天。基于 16S rRNA 基因、comammox amoA 扩增子测序、宏基因组学和批量实验，我们发现 comammox Nitrospira 是主要的氨氧化微生物（AOM），并为厌氧氨氧化菌（AnAOB）提供亚硝酸盐。此外，GAO 主要由 Defluviicoccus 属的细菌主导，在还原硝酸盐方面起着主要作用，而不是亚硝酸盐。荧光原位杂交（FISH）分析证实，Nitrospira 在生物膜的内层中得到了富集。因此，我们提出了一个关于 SNPR 生物膜系统机制的新见解。Comammox Nitrospira 负责生物膜内层的亚硝酸盐和硝酸盐的产生，而 AnAOB 在氨氧化过程中消耗产生的亚硝酸盐。而 GAO 将硝酸盐还原为亚硝酸盐，聚磷菌（PAO）在外层生物膜中通过反硝化除磷将亚硝酸盐转化为氮气。这些发现为 SNPR 生物膜系统提供了新的认识。
