Dissolved oxygen (DO) is an imperative parameter of the activated sludge process (ASP) for wastewater bioremediation. The effect of DO on microbial communities and corresponding metabolic functions in wastewater bioremediation was investigated using next-generation analysis techniques in this study. Illumina-based whole genome sequencing was applied to analyze the composition of the microbial community along with their functional diversity in activated sludge systems operating at three different DO levels. Activated biomass was collected from lab-scale reactors maintained at 1, 2, and 4 mg/L DO levels. Metagenomes were sequenced on an Illumina platform and analyzed using various tools. Results revealed that Proteobacteria phylum and Pseudomonas, Nitrobacter, Thauera, and Alicyclipilus genera were abundant in all reactor samples. Despite distinct DO levels, the microbial communities were conserved and consisted of a common population forming the core group governing the metabolic functions. However, higher diversity was observed at functional level indicating that microbes evolve and adapt to serve their role in a typical ASP. Metabolic pathway related to benzoate dominated at 1 mg/L DO level, while pathways for degradation of aromatic compounds like phenol, toluene, and biphenyl via central metabolic pathway were found dominating at 4 mg/L DO level. Pathways corresponding to homogentisate, naphthalene, cresol, and salicylate degradation enriched at 2 mg/L DO level.

中文翻译：

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活化生物质在不同溶解氧水平下处理工业废水的超基因组学见解。

溶解氧（DO）是用于废水生物修复的活性污泥法（ASP）的必要参数。在这项研究中使用下一代分析技术调查了溶解氧对废水生物修复中微生物群落和相应代谢功能的影响。基于Illumina的全基因组测序被用于分析在三种不同DO水平下运行的活性污泥系统中微生物群落的组成及其功能多样性。从实验室规模的反应器中收集的活化生物质保持在1、2和4 mg / L DO水平。在Illumina平台上对元基因组进行测序，并使用各种工具进行分析。结果表明，在所有反应器样品中，Proteobacteria phylum和Pseudomonas，Nitrobacter，Thauera和Alicyclipilus属均丰富。尽管溶解氧水平不同，但是微生物群落是保守的，并且由形成控制代谢功能核心组的普通人群组成。然而，在功能水平上观察到更高的多样性，表明微生物在典型的ASP中进化并适应其作用。与苯甲酸酯有关的代谢途径在1 mg / L DO水平上占主导地位，而通过中央代谢途径降解芳香族化合物（如苯酚，甲苯和联苯）的途径在4 mg / L DO水平上占主导地位。对应于尿黑酸盐，萘，甲酚和水杨酸盐降解的途径以2 mg / L DO水平富集。在功能水平上观察到更高的多样性，表明微生物在典型的ASP中进化并适应其作用。与苯甲酸酯有关的代谢途径在1 mg / L DO水平上占主导地位，而通过中央代谢途径降解芳香族化合物（如苯酚，甲苯和联苯）的途径在4 mg / L DO水平上占主导地位。对应于纯尿酸盐，萘，甲酚和水杨酸盐降解的途径以2 mg / L DO水平富集。在功能水平上观察到更高的多样性，表明微生物在典型的ASP中进化并适应其作用。与苯甲酸酯有关的代谢途径在1 mg / L DO水平上占主导地位，而通过中央代谢途径降解芳香族化合物（如苯酚，甲苯和联苯）的途径在4 mg / L DO水平上占主导地位。对应于尿黑酸盐，萘，甲酚和水杨酸盐降解的途径以2 mg / L DO水平富集。