Bessarab Irina, Maszenan Abdul Majid, Haryono Mindia A S, Arumugam Krithika, Saw Nay Min Min Thaw, Seviour Robert J, Williams Rohan B H
Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, Singapore.
Nanyang Environment & Water Research Institute (NEWRI), Nanyang Technological University, Singapore, Singapore.
Front Microbiol. 2022 Apr 12;13:834906. doi: 10.3389/fmicb.2022.834906. eCollection 2022.
Members of the genus occur often at high abundances in activated sludge wastewater treatment plants designed to remove phosphorus, where biomass is subjected to alternating anaerobic feed/aerobic famine conditions, believed to favor the proliferation of organisms like . Accumulibacter and other phosphate-accumulating organisms (PAO), and All have a capacity to assimilate readily metabolizable substrates and store them intracellularly during the anaerobic feed stage so that under the subsequent famine aerobic stage, these can be used to synthesize polyphosphate reserves by the PAO and glycogen by Consequently, is described as a glycogen-accumulating organism or GAO. Because they share a similar anaerobic phenotype, it has been proposed that at high abundance, the PAO are out-competed for assimilable metabolites anaerobically, and hence aerobic P removal capacity is reduced. Several whole genome sequences have been published ( Defluviicoccus tetraformis, GAO-HK, and . Defluviicoccus seviourii). The available genomic data of these suggest marked metabolic differences between them, some of which have ecophysiological implications. Here, we describe the whole genome sequence of the type strain , the only cultured member of this genus, and a detailed comparative re-examination of all extant genomes. Each, with one exception, which appears not to be a member of this genus, contains the genes expected of GAO members, in possessing multiple copies of those for glycogen biosynthesis and catabolism, and anaerobic polyhydroxyalkanoate (PHA) synthesis. Both 16S rRNA and genome sequence data suggest that the current recognition of four clades is insufficient to embrace their phylogenetic biodiversity, but do not support the view that they should be re-classified into families other than their existing location in the As expected, considerable variations were seen in the presence and numbers of genes encoding properties associated with key substrate assimilation and metabolic pathways. Two genomes also carried the gene for synthesis of the low-affinity phosphate transport protein, pit, considered by many to distinguish all PAO from GAO. The data re-emphasize the risks associated with extrapolating the data generated from a single population to embrace all members of that genus.
在旨在除磷的活性污泥废水处理厂中，该属的成员常常大量存在，在这些处理厂中，生物质会经历交替的厌氧进料/好氧饥饿条件，据信这种条件有利于诸如Accumulibacter和其他聚磷菌（PAO）等生物的增殖。而且，所有这些生物都有能力吸收易于代谢的底物，并在厌氧进料阶段将其储存在细胞内，这样在随后的饥饿好氧阶段，这些底物可被PAO用于合成聚磷储备，被用于合成糖原。因此，被描述为糖原积累菌或GAO。由于它们具有相似的厌氧表型，有人提出，在高丰度时，PAO在厌氧条件下会在可同化代谢物的竞争中落败，因此好氧除磷能力会降低。已经公布了几个全基因组序列（四形脱卤球菌、GAO-HK和塞维乌里脱卤球菌）。这些可用的基因组数据表明它们之间存在明显的代谢差异，其中一些具有生态生理学意义。在这里，我们描述了该属唯一的培养成员模式菌株的全基因组序列，并对所有现存的全基因组进行了详细的比较重新审视。除了一个似乎不属于该属的例外，每个基因组都包含GAO成员预期的基因，拥有多个糖原生物合成和分解代谢以及厌氧聚羟基脂肪酸酯（PHA）合成的基因。16S rRNA和基因组序列数据都表明，目前对四个进化枝的认识不足以涵盖它们的系统发育生物多样性，但不支持将它们重新分类到除现有在脱卤球菌科之外的其他科的观点。正如预期的那样，在编码与关键底物同化和代谢途径相关特性的基因的存在和数量上，观察到了相当大的差异。两个基因组还携带了用于合成低亲和力磷酸盐转运蛋白pit的基因，许多人认为该基因可区分所有PAO和GAO。这些数据再次强调了将从单个脱卤球菌群体产生的数据外推以涵盖该属所有成员所带来的风险。
