Although the anaerobic ammonium oxidation (anammox) process has attracted attention regarding its application in ammonia wastewater treatment based on its efficiency, the physiological characteristics of anammox bacteria remain unclear because of the lack of pure-culture representatives. The coexistence of heterotrophic bacteria has often been observed in anammox reactors, even in those fed with synthetic inorganic nutrient medium. In this study, we recovered 37 draft genome bins from a long-term-operated anammox column reactor and predicted the metabolic pathway of coexisting bacteria, especially Patescibacteria (also known as Candidate phyla radiation). Genes related to the nitrogen cycle were not detected in Patescibacterial bins, whereas nitrite, nitrate, and nitrous oxide-related genes were identified in most of the other bacteria. The pathway predicted for Patescibacteria suggests the lack of nitrogen marker genes and its ability to utilize poly-N-acetylglucosamine produced by dominant anammox bacteria. Coexisting Patescibacteria may play an ecological role in providing lactate and formate to other coexisting bacteria, supporting growth in the anammox reactor. Patescibacteria-centric coexisting bacteria, which produce anammox substrates and scavenge organic compounds produced within the anammox reactor, might be essential for the anammox ecosystem.

中文翻译：

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长期淡水厌氧氨氧化色谱柱反应器中厌氧细菌与超级杆菌的共代谢

尽管基于其效率，厌氧铵氧化（anammox）工艺在氨水废水处理中的应用引起了人们的关注，但由于缺乏纯培养菌代表，厌氧菌的生理特性仍然不清楚。经常在厌氧氨氧化反应器中观察到异养细菌的共存，即使是在饲喂合成无机营养培养基的反应器中也是如此。在这项研究中，我们从长期运行的厌氧氨氧化色谱柱反应器中回收了37个草图基因组箱，并预测了共存细菌（尤其是杆菌）的代谢途径（也称为候选门辐射）。在杆菌属细菌的箱中未检测到与氮循环相关的基因，而在大多数其他细菌中均鉴定出了亚硝酸盐，硝酸盐和一氧化二氮相关的基因。拟杆菌属的预测途径表明缺乏氮标记基因及其利用占主导地位的厌氧菌产生的聚N-乙酰氨基葡萄糖的能力。共存的杆状杆菌可能在向其他共存细菌提供乳酸和甲酸盐方面发挥生态作用，从而支持厌氧氨氧化反应器中的生长。杆菌属以中心为中心的共存细菌，可能产生厌氧氨氧化底物并清除厌氧氨氧化反应器内产生的有机化合物，这可能对厌氧氨氧化生态系统至关重要。