Inhibition by ammonium at concentrations above 1000 mgN/L is known to harm the methanogenesis phase of anaerobic digestion. We anaerobically digested swine waste and achieved steady state COD-removal efficiency of around 52% with no fatty-acid or H₂ accumulation. As the anaerobic microbial community adapted to the gradual increase of total ammonia-N (NH₃-N) from to  mg/L, the Bacterial and Archaeal communities became less diverse. Phylotypes most closely related to hydrogenotrophic Methanoculleus (36.4%) and Methanobrevibacter (11.6%), along with acetoclastic Methanosaeta (29.3%), became the most abundant Archaeal sequences during acclimation. This was accompanied by a sharp increase in the relative abundances of phylotypes most closely related to acetogens and fatty-acid producers (Clostridium, Coprococcus, and Sphaerochaeta) and syntrophic fatty-acid Bacteria (Syntrophomonas, Clostridium, Clostridiaceae species, and Cloacamonaceae species) that have metabolic capabilities for butyrate and propionate fermentation, as well as for reverse acetogenesis. Our results provide evidence countering a prevailing theory that acetoclastic methanogens are selectively inhibited when the total ammonia-N concentration is greater than ~1000 mgN/L. Instead, acetoclastic and hydrogenotrophic methanogens coexisted in the presence of total ammonia-N of ~2000 mgN/L by establishing syntrophic relationships with fatty-acid fermenters, as well as homoacetogens able to carry out forward and reverse acetogenesis.

中文翻译：

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在处理猪粪的产甲烷反应器中，古细菌和细菌的氨含量高。

已知浓度超过1000 mgN / L的铵盐抑制会损害厌氧消化的甲烷生成阶段。我们厌氧消化了猪粪，实现了稳态COD去除效率约52％，并且没有脂肪酸或H _2的积累。作为厌氧微生物群落适于总氨-N的逐渐增加（NH ₃ -N）从到 ，细菌和古细菌群落成为毫克/升以下多样化。与氢营养型甲烷菌（36.4％）和甲烷短杆菌（11.6％）以及乙酰破伤性甲烷菌（Methanosaeta）最密切相关的基因型（29.3％），成为驯化过程中最丰富的古细菌序列。这是伴随着在种系型最密切相关的产乙酸菌和脂肪酸生产者（的相对丰度急剧增加梭菌，Coprococcus，和Sphaerochaeta）和互养脂肪酸菌（Syntrophomonas，梭菌，梭菌科和梭菌科）具有代谢能力，可进行丁酸和丙酸发酵以及逆向产乙酸。我们的结果提供了与流行的理论相反的证据，该理论认为，当总氨氮浓度大于〜1000 mgN / L时，会抑制乙酰碎屑产甲烷菌。取而代之的是，在总氨氮约为2000 mgN / L的条件下，通过与脂肪酸发酵罐以及能够进行正向和逆向产乙酸的同质产乙酸菌之间的同养关系，在总氨氮含量为〜2000 mgN / L的情况下，同时存在乙酸碎屑和氢营养型产甲烷菌。