Stokholm-Bjerregaard Mikkel, McIlroy Simon J, Nierychlo Marta, Karst Søren M, Albertsen Mads, Nielsen Per H
Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg UniversityAalborg, Denmark.
Front Microbiol. 2017 Apr 27;8:718. doi: 10.3389/fmicb.2017.00718. eCollection 2017.
Understanding the microbiology of phosphorus (P) removal is considered essential to knowledge-based optimization of enhanced biological P removal (EBPR) systems. Biological P removal is achieved in these systems by promoting the growth of organisms collectively known as the polyphosphate accumulating organisms (PAOs). Also considered important to EBPR are the glycogen accumulating organisms (GAOs), which are theorized to compete with the PAOs for resources at the expense of P removal efficiency. Numerous studies have sought to identify the PAOs and their GAOs competitors, with several candidates proposed for each over the last few decades. The current study collectively assessed the abundance and diversity of all proposed PAOs and GAOs in 18 Danish full-scale wastewater treatment plants with well-working biological nutrient removal over a period of 9 years using 16S rRNA gene amplicon sequencing. The microbial community structure in all plants was relatively stable over time. Evidence for the role of the proposed PAOs and GAOs in EBPR varies and is critically assessed, in light of their calculated amplicon abundances, to indicate which of these are important in full-scale systems. Bacteria from the genus were the most abundant of the PAOs. The " Accumulibacter" PAOs were in much lower abundance and appear to be biased by the amplicon-based method applied. The genera , and were identified as abundant putative PAO that require further research attention. Interestingly, the actinobacterial and sbr-gs28 phylotypes were among the most abundant of the putative GAOs. Members of the genera , the family Competibacteraceae, and the spb280 group were also relatively abundant in some plants. Despite observed high abundances of GAOs (periodically exceeding 20% of the amplicon reads), P removal performance was maintained, indicating that these organisms were not outcompeting the PAOs in these EBPR systems. Phylogenetic diversity within each of the PAOs and GAOs genera was observed, which is consistent with reported metabolic diversity for these. Whether or not key traits can be assigned to sub-genus level clades requires further investigation.
了解生物除磷的微生物学对于基于知识的强化生物除磷（EBPR）系统优化至关重要。在这些系统中，通过促进统称为聚磷菌（PAO）的微生物生长来实现生物除磷。糖原积累菌（GAO）对EBPR也很重要，理论上它们会与PAO争夺资源，从而降低除磷效率。众多研究试图识别PAO及其GAO竞争者，在过去几十年里，每种类型都有多个候选者被提出。本研究通过16S rRNA基因扩增子测序，对18个丹麦全尺寸污水处理厂中所有已提出的PAO和GAO的丰度和多样性进行了综合评估，这些污水处理厂在9年时间里具有良好的生物营养物去除效果。所有工厂的微生物群落结构随时间相对稳定。根据计算出的扩增子丰度，对已提出的PAO和GAO在EBPR中的作用证据进行了批判性评估，以表明哪些在全尺寸系统中很重要。某属细菌是PAO中最丰富的。“聚磷菌属”PAO的丰度要低得多，似乎受到所应用的基于扩增子方法的影响。某属、某属和某属被确定为丰富的假定PAO，需要进一步研究关注。有趣的是，放线菌某型和sbr-gs28系统型是假定GAO中最丰富的。某属成员、竞争杆菌科和spb280组在一些工厂中也相对丰富。尽管观察到GAO丰度很高（偶尔超过扩增子读数的20%），但除磷性能仍得以维持，这表明在这些EBPR系统中，这些微生物并没有胜过PAO。在每个PAO和GAO属内都观察到了系统发育多样性，这与报道的这些属的代谢多样性一致。是否可以将关键特征分配到亚属水平的进化枝还需要进一步研究。
