BACKGROUND The metabolic capacities of anammox bacteria and associated microbial community interactions in partial-nitritation anammox (PNA) reactors have received considerable attention for their crucial roles in energy-efficient nitrogen removal from wastewater. However, a comprehensive understanding of how abiotic and biotic factors shape bacterial community assembly in PNA reactors is not well reported. RESULTS Here, we used integrated multi-omics (i.e., high-throughput 16S rRNA gene, metagenomic, metatranscriptomic, and metaproteomic sequencing) to reveal how abiotic and biotic factors shape the bacterial community assembly in a lab-scale one-stage PNA reactor treating synthetic wastewater. Analysis results of amplicon sequences (16S rRNA gene) from a time-series revealed distinct relative abundance patterns of the key autotrophic bacteria, i.e., anammox bacteria and ammonia-oxidizing bacteria (AOB), and the associated heterotrophic populations in the seed sludge and the sludge at the new stable state after deterioration. Using shotgun metagenomic sequences of anammox sludge, we recovered 58 metagenome-assembled genomes (MAGs), including 3 MAGs of anammox bacteria and 3 MAGs of AOB. The integrated metagenomic, metatranscriptomic, and metaproteomic data revealed that nitrogen metabolism is the most active process in the studied PNA reactor. The abundant heterotrophs contribute to the reduction of nitrate to nitrite/ammonium for autotrophic bacteria (anammox bacteria and AOB). Genomic and transcriptomic data revealed that the preference for electron donors of the dominant heterotrophs in different bacterial assemblages (seed and new stable state) varied along with the shift in anammox bacteria that have different metabolic features in terms of EPS composition. Notably, the most abundant heterotrophic bacteria in the reactor were more auxotrophic than the less abundant heterotrophs, regarding the syntheses of amino acids and vitamins. In addition, one of the abundant bacteria observed in the bacterial community exhibited highly transcribed secretion systems (type VI). CONCLUSIONS These findings provide the first insight that the bacterial communities in the PNA reactor are defined by not only abiotic factors (operating mode) but also metabolic interactions, such as nitrogen metabolism, exchange of electron donors, and auxotrophies.

中文翻译：

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使用集成的多组学方法研究一阶段部分硝化厌氧氨氧化反应器中操作模式和微生物相互作用对细菌群落组装的影响。

背景技术在部分硝化厌氧氨（PNA）反应器中厌氧氨氧化细菌的代谢能力和相关的微生物群落相互作用因其在从废水中高效去除氮中的关键作用而受到了广泛的关注。然而，关于非生物和生物因素如何影响PNA反应器中细菌群落组装的全面了解尚无充分报道。结果在这里，我们使用了集成的多组学（即高通量16S rRNA基因，宏基因组学，元转录组学和元蛋白质组学测序）来揭示非生物和生物因素如何影响实验室规模的一级PNA反应器处理中的细菌群落组装。合成废水。时间序列的扩增子序列（16S rRNA基因）的分析结果显示，关键自养细菌的相对相对丰度模式不同，即污泥中的厌氧细菌和氨氧化细菌（AOB），以及相关的异养种群，其污泥和变质后处于新的稳定状态的污泥。使用厌氧菌污泥的shot弹枪宏基因组序列，我们回收了58个由基因组组装的基因组（MAG），其中包括3株厌氧菌细菌MAG和3株AOB MAG。整合的宏基因组学，转录组学和蛋白质组学数据表明，氮代谢是所研究的PNA反应器中最活跃的过程。丰富的异养菌有助于将自养细菌（厌氧菌和AOB）的硝酸盐还原为亚硝酸盐/铵。基因组和转录组数据显示，在不同细菌组合（种子和新的稳定状态）中，优势异养生物对电子供体的偏好随着EPS组成具有不同代谢特征的厌氧细菌的变化而变化。值得注意的是，就氨基酸和维生素的合成而言，反应器中最丰富的异养细菌比不那么丰富的异养细菌更具营养缺陷性。此外，在细菌群落中观察到的丰富细菌之一表现出高度转录的分泌系统（VI型）。结论这些发现提供了第一个见解，即PNA反应器中的细菌群落不仅由非生物因素（工作模式）定义，还由代谢相互作用（例如氮代谢，电子供体交换，