Performance of a bioreactor is affected by complex microbial consortia that regulate system functional processes. Studies so far, however, have mainly emphasized the selective pressures imposed by operational conditions (i.e., deterministic external physicochemical variables) on the microbial community as well as system performance, but have overlooked direct effects of the microbial community on system functioning. Here, using a bioreactor with ammonium as the sole substrate under controlled operational settings as a model system, we investigated succession of the bacterial community after a disturbance and its impact on nitrification and anammox (anaerobic ammonium oxidation) processes with fine-resolution time series data. System performance was quantified as the ratio of the fed ammonium converted to anammox-derived nitrogen gas (N₂) versus nitrification-derived nitrate (npNO₃⁻). After the disturbance, the N₂/npNO₃⁻ ratio first decreased, then recovered, and finally stabilized until the end. Importantly, the dynamics of N₂/npNO₃⁻ could not be fully explained by physicochemical variables of the system. In comparison, the proportion of variation that could be explained substantially increased (tripled) when the changes in bacterial composition were taken into account. Specifically, distinct bacterial taxa tended to dominate at different successional stages, and their relative abundances could explain up to 46% of the variation in nitrogen removal efficiency. These findings add baseline knowledge of microbial succession and emphasize the importance of monitoring the dynamics of microbial consortia for understanding the variability of system performance.

中文翻译：

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自养性脱氮生物反应器发生扰动后与细菌群落演替相对应的系统性能。

生物反应器的性能受到调节系统功能过程的复杂微生物联盟的影响。然而，迄今为止的研究主要强调了操作条件（即确定的外部物理化学变量）对微生物群落以及系统性能所施加的选择性压力，但是却忽略了微生物群落对系统功能的直接影响。在这里，我们使用以氨为唯一底物的生物反应器，在受控的操作设置下作为模型系统，以精细的时间序列数据调查了扰动后细菌群落的演替及其对硝化和厌氧氨氧化（厌氧铵氧化）过程的影响。 。系统性能以进料铵转化为厌氧氨氮（N₂）与硝化衍生的硝酸盐（npNO ₃ ^- ）。扰动之后，将N ₂ / npNO ₃ ^-比先下降，再恢复，并最终稳定，直到结束。重要的是，N的动力学₂ / npNO ₃ ^-无法通过系统的理化变量充分解释。相比之下，当考虑到细菌组成的变化时，可以解释的变化比例显着增加（三倍）。具体而言，不同的细菌类群倾向于在不同的演替阶段占主导地位，它们的相对丰度可以解释多达46％的脱氮效率变化。这些发现增加了微生物演替的基础知识，并强调了监测微生物群落动态以了解系统性能变异的重要性。