Distinct comammox Nitrospira catalyze ammonia oxidation in a full-scale groundwater treatment bioreactor under copper limited conditions
Distinct comammox Nitrospira catalyze ammonia oxidation in a full-scale groundwater treatment bioreactor under copper limited conditions
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DOI：
10.1016/j.watres.2021.117986
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发表时间：
2022-02-15
期刊：
影响因子：
12.8
通讯作者：
Matsuura, Norihisa
中科院分区：
文献类型：
--
作者：
Koike, Kazuyoshi;Smith, Garrett J.;Matsuura, Norihisa
微生物氨氧化是水处理过程中生物脱氮的初始硝化步骤，完全氨氧化（comammox）细菌的发现为该功能组增添了一个新成员。在生物技术工艺设计和优化中，识别和了解负责去除铵的主要微生物非常重要。在这项研究中，我们使用全尺寸生物反应器处理地下水中的铵（9.3 +/- 0.5 mg NH4+-N/L），并研究了存在的关键氨氧化原核生物。在类似于生物反应器运行 700 天的过程中，地下水氨被稳定且有效地氧化。生物反应器群落的 16S rRNA 基因扩增子测序显示 Nitrospira 丰度较高（12.5-45.9%），其中占主导地位的序列变异（3.5-37.8%）与 Candidatus Nitrospira ninsa 关系最密切。此外，对氨氧化标记基因amoA的分析表明存在两个不同的comammox Nitrospira种群，然而，其中只有一个种群的相对丰度与氨氧化速率密切相关，并且表达强烈。运行380天后，将铜线浸入0.04-0.06 m(2)/m(3)槽的反应器中，导致一种离散的comammox Nitrospira种群的丰度逐渐增加。然而，铜剂量的进一步增加（0.08 m(2)/m(3) 池）将最丰富的氨氧化菌群逆转为亚硝化单胞菌。这些结果表明，comammox Nitrospira 能够在没有外源营养物的情况下有效去除地下水中的铵，但添加铜可以刺激comammox Nitrospira 或导致亚硝化单胞菌占主导地位，具体取决于剂量。
Microbial ammonia oxidation is the initial nitrification step used in biological nitrogen-removal during water treatment processes, and the discovery of complete ammonia-oxidizing (comammox) bacteria added a novel member to this functional group. It is important to identify and understand the predominant microorganisms responsible for ammonium removal in biotechnological process design and optimization. In this study, we used a full-scale bioreactor to treat ammonium in groundwater (9.3 +/- 0.5 mg NH4+-N/L) and investigated the key ammonia-oxidizing prokaryotes present. The groundwater ammonium was stably and efficiently oxidized throughout similar to 700 days of bioreactor operation. 16S rRNA gene amplicon sequencing of the bioreactor community showed a high abundance of Nitrospira (12.5-45.9%), with the dominant sequence variant (3.5-37.8%) most closely related to Candidatus Nitrospira nitrosa. Furthermore, analyses of amoA, the marker gene for ammonia oxidation, indicated the presence of two distinct comammox Nitrospira populations, however, the relative abundance of only one of these populations was strongly correlated to ammonia oxidation rates and was robustly expressed. After 380 days of operation copper wires were immersed into the reactor at 0.04-0.06 m(2)/m(3) tank, which caused a gradual abundance increase of one discrete comammox Nitrospira population. However, further increase of the copper dosing (0.08 m(2)/m(3) tank) inverted the most abundant ammonia-oxidizing population to Nitrosomonas sp. These results indicate that comammox Nitrospira were capable of efficient ammonium removal in groundwater without exogenous nutrients, but copper addition can stimulate comammox Nitrospira or lead to dominance of Nitrosomonas depending on dosage.