Linking Genome-Centric Metagenomics to Kinetic Analysis Reveals the Regulation Mechanism of Hydroxylamine in Nitrite Accumulation of Biological Denitrification.
Linking Genome-Centric Metagenomics to Kinetic Analysis Reveals the Regulation Mechanism of Hydroxylamine in Nitrite Accumulation of Biological Denitrification.
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DOI：
10.1021/acs.est.2c01914
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发表时间：
2022-06
影响因子：
11.4
通讯作者：
Zhengzhe Zhang;Yu Zhang;Zhijian Shi;Yinguang Chen
中科院分区：
文献类型：
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作者：
Zhengzhe Zhang;Yu Zhang;Zhijian Shi;Yinguang Chen
鉴于羟胺在不同硝化系统中的积累及其对后续反硝化过程的潜在调控机制，本研究对其进行了研究。羟胺(>；0.5mgN/L)通过抑制亚硝酸还原酶及其电子传递模块(复合体III和细胞色素c)的活性，立即诱导活性污泥中亚硝酸盐的积累。在低C/N条件下，长期接触0.5~2.5mGN/L羟胺加速了反硝化向反硝化的功能转化。然而，以基因组为中心的元基因组学表明，一个完整的而不是截短的反硝化子Thauera aminoaromatica TJ127富含，主要负责反硝化群落的乙酸盐储存和硝酸盐还原。有趣的是，它的富集会导致亚硝酸盐的生成和还原，但在碳限制的条件下，它只会将硝酸盐还原为亚硝酸盐(C/N≤3.0)。因此，在活性污泥中，它对羟胺的耐受性高于同时存在的表型反硝化菌。此外，由于其在盛宴阶段具有较高的缺氧存储能力，这种浓缩通过降低盛宴/饥荒比而变得高度专业化，因此在没有羟胺的情况下仍然保持了令人满意的脱氮性能。这些结果表明，硝化过程中羟胺的短暂释放可能会干扰后续的反硝化代谢，但其持续积累有利于实现反硝化，从而为主流厌氧氨氧化提供稳定的亚硝酸盐。
Given hydroxylamine accumulation in various nitrification systems and its potential mechanism in regulating the subsequent denitrification process were unraveled in this study. Hydroxylamine (>0.5 mgN/L) immediately induced nitrite accumulation of activated sludge by inhibiting the activities of nitrite reductases and their electron transport modules (Complex III and cytochrome c). Moreover, long-term exposure to 0.5-2.5 mgN/L hydroxylamine accelerated the functional transformation from denitrification to denitratation under low C/N conditions. However, genome-centric metagenomics indicated that a genotypic complete rather than truncated denitrifier Thauera aminoaromatica TJ127 was enriched and mainly responsible for acetate storage and nitrate reduction of the denitratation community. Interestingly, its enrichment resulted in nitrite production and reduction sequentially but reduced nitrate only to nitrite under carbon-limited conditions (C/N ≤ 3.0). Thus, it showed higher tolerance to hydroxylamine than the concurrent phenotype denitrifiers in activated sludge. Moreover, due to its higher anoxic storage capability in the feast phase, this enrichment became highly specialized by decreasing the feast/famine ratio, and thus a satisfactory denitratation performance was still maintained without hydroxylamine. These results suggested that the transient release of hydroxylamine from nitrification may interfere with subsequent denitrification metabolism, but its continuous accumulation is beneficial for achieving denitratation, which could steadily provide nitrite for mainstream anammox.