Accumulibacter is a well-known group of organisms, typically considered to be polyphosphate accumulating organisms (PAOs), but potentially capable of glycogen accumulating organism (GAO) metabolism under limiting influent phosphate levels. Metabolic features of Accumulibacter are typically linked to its phylogenetic identity at the Type or clade level, though it is unclear the extent to which Accumulibacter diversity can correlate with its capacity to perform P removal. This paper investigates the fine-scale diversity of Accumulibacter and its link with enhanced biological phosphorus removal (EBPR) performance under various operating conditions, to understand the conditions and community structure leading to successful and unsuccessful EBPR operation. For this purpose, the organic carbon feeding rate and total organic carbon concentration were varied during three distinct operational periods, where influent phosphate was never limiting. Accumulibacter was always the dominant microbial group (>80% of all bacteria according to quantitative fluorescence in situ hybridisation - FISH) and low levels of Competibacter and other GAOs were consistently observed (<15% of all bacteria). Steady state was achieved in each of the three periods, with average phosphorus removal levels of 36%, 99% and >99%, respectively. Experimentally determined stoichiometric activity supported the expression of a mixed PAO/GAO metabolism in the first steady state period and the typical PAO metabolism in the other two steady state periods. FISH quantification and amplicon sequencing of the polyphosphate kinase (ppk1) functional gene indicated that Accumulibacter clade IIC was selected in the first steady state period, which shifted to clade IA after decreasing the carbon feeding rate in steady state period 2, and finally shifted back to clade IIC in the third steady state period. Fine-resolution Ppk-based phylogenetic analysis revealed three different clusters within Accumulibacter clade IIC, where clusters IICii and IICiii were linked to poor EBPR performance in period 1, and cluster IICi was linked to good EBPR performance in period 3. This study shows that the deterioration of EBPR processes through GAO activity at non-limiting P concentrations can be linked to organisms that are typically classified as PAOs, not only to known GAOs such as Competibacter. Intra-clade phylogenetic diversity within Accumulibacter showed that some clusters actually behave similarly to GAOs even without influent phosphate limitation. This study highlights the need to closely re-examine traditional interpretations regarding the link between the microbial community composition and identity with the performance and metabolism of EBPR systems.

Accumulibacter是公知的组的生物体，通常被认为是聚磷生物体烯烃（PAO），但是潜在地能够根据限制流入磷酸盐水平糖原累积生物体（GAO）代谢的。尽管尚不清楚Accumulibacter多样性与P去除能力的相关程度，但Accumulibacter的代谢特征通常与其在类型或进化枝水平上的系统发育同一性相关。本文研究了积累细菌的细微多样性并将其与在各种操作条件下增强的生物除磷（EBPR）性能相关联，以了解导致EBPR操作成功和失败的条件和社区结构。为此目的，在三个不同的操作期间内，改变有机碳的进料速度和总有机碳浓度，其中进水磷酸盐从未受到限制。积累细菌一直是主要的微生物组（根据定量荧光原位杂交-FISH，> 80％的细菌为细菌）和低水平的竞争杆菌并始终观察到其他GAO（占所有细菌的<15％）。在这三个阶段的每个阶段均达到了稳态，平均除磷水平分别为36％，99％和> 99％。实验确定的化学计量活性支持在第一个稳态时期中PAO / GAO混合代谢的表达以及在其他两个稳态时期中典型的PAO代谢的表达。FISH量化和多磷酸激酶（的扩增子测序ppk1）功能基因表明Accumulibacter进化枝IIC在所述第一稳定状态期间，该移动减小在稳定状态期间2中的碳供给速度后，进化枝IA选择，最后移回进化枝IIC处于第三稳态时期。高分辨率Ppk基于系统发生分析显示三种不同的簇内Accumulibacter进化枝IIC，其中簇IICii和IICiii被链接到EBPR性能差在时期1和集群IICi被挂好EBPR性能在周期3本研究表明，EBPR过程的恶化通过非限制性P浓度下的GAO活性可以将其与通常被归类为PAO的生物相关联，而不仅与已知的GAO（如Competibacter）有关。积累细菌内的进化枝内系统发生多样性结果表明，即使没有进水磷酸盐的限制，某些团簇的行为实际上也与GAO相似。这项研究强调需要仔细检查有关微生物群落组成和特性与EBPR系统的性能和代谢之间的联系的传统解释。