The microbial ecosystems of the sludge were characterized in terms of the core community structure, functional pathways, and functional redundancy through Illumina MiSeq sequencing and PICRUSt analysis on the activated sludge (AS) samples from an extended activated aeration process. Based on the identified OTU distribution, we identified 125 core community genera, including 3 abundant core genera and 21 intermittent abundant core genera. Putative genera Nitrosomonas, Nitrotoga, Zoogloea, Novosphingobium, Thermomonas, Amaricoccus, Tetrasphaera, Candidatus Microthrix, and Haliscomenobacter, which are associated with functions of nitrifying, denitrifying, phosphorus accumulating, and bulking and foaming, were found to present as the core community organisms in the AS sampled from the conventional extended aeration AS processes. The high-abundant nitrogen metabolic pathways were associated with nitrate reduction to ammonium (DNRA and ANRA), denitrification, and nitrogen fixation, while the ammonia oxidation-related genes (amo) were rarely annotated in the AS samples. Strict functional redundancy was not found with the AS ecosystem as it showed a high correlation between the community composition similarity and function similarity. In addition, the classified dominant core genera community was found to be sufficient to characterize the functionality of AS, which could invigorate applications of 16S rDNA MiSeq sequencing and PICRUSt for the prediction of functions of AS ecosystems.

中文翻译：

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解开活性污泥中生态系统的社区结构：核心社区，功能和功能冗余。

通过Illumina MiSeq测序和对来自扩展活化曝气过程的活性污泥（AS）样品的PICRUSt分析，对污泥的微生物生态系统进行了核心群落结构，功能途径和功能冗余的表征。根据确定的OTU分布，我们确定了125个核心社区属，包括3个丰富的核心属和21个间歇性的丰富核心属。推定的亚硝化单胞菌，亚硝基多毛菌，动球菌，新孢子虫，嗜热性单胞菌，链球菌，四球菌，微丝念珠菌和螺旋杆菌属细菌，它们具有硝化，反硝化，磷积累，膨化和起泡沫的功能，是它们的核心群落生物。 AS是从常规扩展曝气AS过程中取样的。高丰度的氮代谢途径与硝酸盐还原成铵（DNRA和ANRA），反硝化和固氮有关，而在AS样品中很少注释与氨氧化有关的基因（amo）。AS生态系统未发现严格的功能冗余，因为它在社区组成相似性和功能相似性之间显示出高度相关性。此外，已发现分类的优势核心属群落足以描述AS的功能，这可以激发16S rDNA MiSeq测序和PICRUSt在AS生态系统功能预测中的应用。而在AS样品中很少注释与氨氧化有关的基因（amo）。AS生态系统未发现严格的功能冗余，因为它在社区组成相似性和功能相似性之间显示出高度相关性。此外，已发现分类的优势核心属群落足以描述AS的功能，这可以激发16S rDNA MiSeq测序和PICRUSt在AS生态系统功能预测中的应用。而在AS样品中很少注释与氨氧化有关的基因（amo）。AS生态系统未发现严格的功能冗余，因为它在社区组成相似性和功能相似性之间显示出高度相关性。此外，已发现分类的优势核心属群落足以描述AS的功能，这可以激发16S rDNA MiSeq测序和PICRUSt在AS生态系统功能预测中的应用。