Selective Organic Carbon Enrichment Influences Nitrous Oxide Reduction by Denitrifiers: Electron Competition Insights
Selective Organic Carbon Enrichment Influences Nitrous Oxide Reduction by Denitrifiers: Electron Competition Insights
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DOI：
10.1021/acsestwater.2c00161
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
Yingrui Liu;Yanying He;Shuqi Ren;Tingting Zhu;Yiwen Liu
中科院分区：
文献类型：
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作者：
Yingrui Liu;Yanying He;Shuqi Ren;Tingting Zhu;Yiwen Liu
减少废水处理厂 (WWTP) 一氧化二氮 (N2O) 排放的一种有前途的方法是富集能够调节 N2O 减少的高效异养反硝化菌。具体的反硝化群落结构可能受到有机碳类型的影响，但其相应的N2O还原能力和电子竞争机制仍不清楚。在本研究中，系统地探讨了富含甲醇、乙醇和乙酸钠的反硝化剂在不同碳负载率下的 N2O 还原能力。通过微生物群落和生化实验相结合，研究了电子竞争对N2O还原的影响。结果表明，富含乙酸钠的反硝化菌含有丰富的N2O还原酶（Nos）基因，始终保持最高的N2O还原率（rN2O）。然而，多个电子受体（即NO3和/或NO2）的同时存在导致rN2O对富含乙酸钠的反硝化剂具有更高的敏感性，这可以解释在充足的碳供应下N2O还原率的下降。然而，在有机碳供应不足的情况下，Nos面临来自上游电子库的更激烈的电子竞争，导致更多的N2O积累。此外，电子分布的定量研究证实了上述 N2O 还原数据。需要进一步研究来优化有机碳供给策略，以利用反硝化器作为污水处理厂的有效 N2O 汇。
A promising approach to reduce nitrous oxide (N2O) emission from wastewater treatment plants (WWTPs) would be to enrich highly efficient heterotrophic denitrifiers that are capable of regulating N2O reduction. The specific denitrifying community structure could be influenced by the types of organic carbon fed, while their corresponding N2O reduction capacity and electron competition mechanism remain unclear. In this study, the N2O reduction capacity by methanol-, ethanol-, and sodium acetate-enriched denitrifiers was systematically explored at varying carbon-loading rates. The effect of electron competition on N2O reduction was investigated by the combination of the microbial community and biochemical experiments. The results indicated that sodium acetate-enriched denitrifiers harboring abundant N2O reductase (Nos) genes invariably maintained the highest N2O reduction rate (rN2O). However, the concurrent presence of multiple electron acceptors (i.e., NO3–and/or NO2–) resulted in the higher susceptibility ofrN2Ofor sodium acetate-enriched denitrifiers, which could explain the decrease in the N2O reduction rate under sufficient carbon supply. However, under insufficient organic carbon supply, Nos was confronted with fiercer electron competition from the upstream electron pool, causing more N2O accumulation. Moreover, a quantitative investigation of the electron distribution corroborated the aforementioned N2O reduction data. Further studies are warranted to optimize organic carbon-feeding strategies to utilize denitrifiers as an effective N2O sink at WWTPs.