Albertsen Mads, McIlroy Simon J, Stokholm-Bjerregaard Mikkel, Karst Søren M, Nielsen Per H
Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University Aalborg, Denmark.
Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg UniversityAalborg, Denmark; Krüger A/SAalborg, Denmark.
Front Microbiol. 2016 Jul 4;7:1033. doi: 10.3389/fmicb.2016.01033. eCollection 2016.
Enhanced biological phosphorus removal (EBPR) is widely used to remove phosphorus from wastewater. The process relies on polyphosphate accumulating organisms (PAOs) that are able to take up phosphorus in excess of what is needed for growth, whereby phosphorus can be removed from the wastewater by wasting the biomass. However, glycogen accumulating organisms (GAOs) may reduce the EBPR efficiency as they compete for substrates with PAOs, but do not store excessive amounts of polyphosphate. PAOs and GAOs are thought to be phylogenetically unrelated, with the model PAO being the betaproteobacterial "Candidatus Accumulibacter phosphatis" (Accumulibacter) and the model GAO being the gammaproteobacterial "Candidatus Competibacter phosphatis". Here, we report the discovery of a GAO from the genus Propionivibrio, which is closely related to Accumulibacter. Propionivibrio sp. are targeted by the canonical fluorescence in situ hybridization probes used to target Accumulibacter (PAOmix), but do not store excessive amounts of polyphosphate in situ. A laboratory scale reactor, operated to enrich for PAOs, surprisingly contained co-dominant populations of Propionivibrio and Accumulibacter. Metagenomic sequencing of multiple time-points enabled recovery of near complete population genomes from both genera. Annotation of the Propionivibrio genome confirmed their potential for the GAO phenotype and a basic metabolic model is proposed for their metabolism in the EBPR environment. Using newly designed fluorescence in situ hybridization (FISH) probes, analyses of full-scale EBPR plants revealed that Propionivibrio is a common member of the community, constituting up to 3% of the biovolume. To avoid overestimation of Accumulibacter abundance in situ, we recommend the use of the FISH probe PAO651 instead of the commonly applied PAOmix probe set.
强化生物除磷（EBPR）被广泛用于去除废水中的磷。该过程依赖于聚磷积累微生物（PAO），它们能够摄取超过生长所需量的磷，从而通过排出生物质从废水中去除磷。然而，糖原积累微生物（GAO）可能会降低EBPR效率，因为它们与PAO竞争底物，但不会储存过量的聚磷。PAO和GAO在系统发育上被认为没有亲缘关系，典型的PAO是β-变形菌纲的“聚磷菌属（Candidatus Accumulibacter phosphatis）”（聚磷菌属），典型的GAO是γ-变形菌纲的“竞争聚磷菌属（Candidatus Competibacter phosphatis）”。在此，我们报告了从丙酸弧菌属中发现的一种GAO，它与聚磷菌属密切相关。丙酸弧菌属物种被用于靶向聚磷菌属的标准荧光原位杂交探针（PAOmix）靶向，但在原位不会储存过量的聚磷。一个用于富集PAO的实验室规模反应器中，令人惊讶地同时含有丙酸弧菌属和聚磷菌属的共优势菌群。对多个时间点进行宏基因组测序，使得能够从这两个属中获得近乎完整的种群基因组。对丙酸弧菌属基因组的注释证实了它们具有GAO表型的潜力，并提出了它们在EBPR环境中的基本代谢模型。使用新设计的荧光原位杂交（FISH）探针，对全规模EBPR工厂的分析表明，丙酸弧菌属是群落中的常见成员，占生物体积的比例高达3%。为避免原位高估聚磷菌属的丰度，我们建议使用FISH探针PAO651，而不是常用的PAOmix探针组。
