The ability of anammox bacteria to utilize organic matter has drawn extensive attention. However, the metabolic discrepancies between autotrophic and mixotrophic anammox consortia need to be further explored. Here, microbial transcript and metabolomic analysis were conducted for the samples harvested in the reactors and batch assays to investigate the phenotype discrepancies and intrinsic causes in autotrophic and mixotrophic anammox consortia. Results showed that metabolically active community structures did not show significant difference between autotrophic and mixotrophic anammox consortia (C/N = 0.3). Changes in the metabolic state were the main cause for those discrepancies in virtue of the added acetate oxidized via the acetyl-CoA pathway by mixotrophic anammox bacteria. At C/N ratio of 0.3, anammox activity was obviously promoted compared to that in the autotrophic condition, due to higher levels of NADH and NAD⁺, as well as ATP consumption. Mixotrophic anammox consortia were found to yield more biomass, resulting from enhanced purine, pyrimidine, and putrescine synthetic pathways for regulating bacterial growth. Up-regulated amino sugar and nucleotide sugar metabolism pathways participating in regulating more extracellular polysaccharides secreted by mixotrophic anammox consortia. In adverse environment with higher COD concentration, more extracellular proteins were produced by anammox consortia to protect themselves and amino acids also accumulated in the cell. This study provides useful information to catch the optimal metabolism way of anammox consortia and accelerate anammox bacterial cultivation or reactor startup for wastewater treatment.

中文翻译：

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微生物转录和代谢组学分析揭示了自养和混养厌氧菌团中不同的代谢途径

厌氧氨氧化细菌利用有机物的能力已引起广泛关注。然而，自养和混养厌氧菌团之间的代谢差异有待进一步探讨。在这里，对在反应器中收集的样品进行了微生物转录和代谢组学分析，并进行了批次分析，以研究自养和杂养厌氧菌团的表型差异和内在原因。结果显示，在自养和混养厌氧菌团之间，代谢活跃的群落结构没有显示出显着差异（C / N = 0.3）。代谢状态的变化是这些差异的主要原因，这是由于混合营养型厌氧细菌通过乙酰辅酶A途径氧化了添加的乙酸盐。在C / N比为0.3的情况下，⁺以及ATP消耗量。混合营养型厌氧菌团被发现产生更多的生物量，这是由于嘌呤，嘧啶和腐胺的合成途径增强了细菌的生长。上调的氨基糖和核苷酸糖代谢途径参与调节由混合营养厌氧菌团分泌的更多的细胞外多糖。在具有较高COD浓度的不利环境中，厌氧氨纶联盟会产生更多的细胞外蛋白来保护自身，并且氨基酸也积聚在细胞中。这项研究提供了有用的信息，以捕捉厌氧菌团的最佳代谢方式，并加速厌氧菌的培养或废水处理反应器的启动。