The Key Laboratory of Resources and Environmental Systems Optimization, Ministry of Education, College of Environmental Science and Engineering, North China Electric Power University, Beijing 102206, China.
CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing 100049, China.
J Environ Sci (China). 2021 Apr;102:273-282. doi: 10.1016/j.jes.2020.09.039. Epub 2020 Oct 11.
Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are two microbial groups mediating nitrification, yet little is presently known about their abundances and community structures at the transcriptional level in wastewater treatment systems (WWTSs). This is a significant issue, as the numerical abundance of AOA or AOB at the gene level may not necessarily represent their functional role in ammonia oxidation. Using amoA genes as molecular markers, this study investigated the transcriptional abundance and community structure of active AOA and AOB in 14 WWTSs. Quantitative PCR results indicated that the transcriptional abundances of AOB amoA (averaged: 1.6 × 10 copies g dry sludge) were higher than those of AOA (averaged: 3.4 × 10 copies g dry sludge) in all WWTSs despite several higher abundances of AOA amoA at the gene level. Moreover, phylogenetic analysis demonstrated that Nitrosomonas europaea and unknown clusters accounted for 37.66% and 49.96% of the total AOB amoA transcripts, respectively, suggesting their dominant role in driving ammonia oxidation. Meanwhile, AOA amoA transcripts were only successfully retrieved from 3 samples, and the Nitrosospaera sister cluster dominated, accounting for 83.46%. Finally, the substrate utilization kinetics of different AOA and AOB species might play a fundamental role in shaping their niche differentiation, community composition, and functional activity. This study provides a basis for evaluating the relative contributions of ammonia-oxidizing microorganisms (AOMs) to nitrogen conversions in WWTSs.
氨氧化细菌 (AOB) 和古菌 (AOA) 是介导硝化作用的两种微生物群，但目前对于它们在废水处理系统 (WWTS) 中转录水平上的丰度和群落结构知之甚少。这是一个重要的问题，因为 AOA 或 AOB 在基因水平上的数量丰度不一定代表它们在氨氧化中的功能作用。本研究使用 amoA 基因作为分子标记，调查了 14 个 WWTS 中活性 AOA 和 AOB 的转录丰度和群落结构。定量 PCR 结果表明，尽管在基因水平上 AOA amoA 的丰度较高，但所有 WWTS 中 AOB amoA 的转录丰度（平均：1.6×10 拷贝 g 干污泥）均高于 AOA（平均：3.4×10 拷贝 g 干污泥）。此外，系统发育分析表明，Nitrosomonas europaea 和未知聚类分别占总 AOB amoA 转录本的 37.66%和 49.96%，表明它们在驱动氨氧化中起主导作用。同时，仅从 3 个样品中成功检索到 AOA amoA 转录本，且 Nitrosospaera 姐妹聚类占主导地位，占 83.46%。最后，不同 AOA 和 AOB 物种的底物利用动力学可能在塑造它们的生态位分化、群落组成和功能活性方面发挥着根本作用。本研究为评估氨氧化微生物 (AOM) 在 WWTS 中对氮转化的相对贡献提供了依据。
