Department of Environmental Science and Engineering, School of Energy and Environment, Wuxi Engineering Research Center of Taihu Lake Water Environment, Southeast University, Nanjing, Jiangsu 210096, China; Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China.
Nanjing Research Institute of Environmental Protection, Nanjing Environmental Protection Bureau, Nanjing, Jiangsu 210013, China.
Sci Total Environ. 2022 Oct 10;842:156911. doi: 10.1016/j.scitotenv.2022.156911. Epub 2022 Jun 23.
The impacts of quorum sensing (QS) on nanoparticle (NP)-stressed biological nitrogen removal (BNR) system have seldom been addressed yet. In this study, the contributions of endogenous N-acyl-homoserine lactone (AHL)-based QS regulation to the BNR system's adaptation to the zinc oxide (ZnO) NP stress and its recovery potential were systematically investigated. Although 1 mg/L ZnO NPs exerted little impact on the BNR system, chronic exposure to 10 mg/L ones depressed the system's BNR performance which irreversibly impaired the nitrification process even when the system entered the recovery period with no NP added anymore. Meanwhile, ZnO NPs exhibited hormesis effects on the production of AHLs and extracellular polymeric substance (EPS), and activities of superoxide dismutase and catalase. During the ZnO NP exposure period, C-HSL, C-HSL, and C-HSL were discovered to be positively associated with nitrogen removal efficiency, tightly-bound EPS production, and antioxidase activities. Besides, the shifts of Nitrospira, Dechloromonas, Aeromonas, Acinetobacter, Delftia, and Bosea were expected to determine the AHL's dynamic distribution. During the system's recovery stage, Dechloromonas replaced Candidatus_Competibacter as the dominant denitrification-related genus. Dechloromonas abundance elevated with the increased contents of C-HSL in the aqueous and EPS phases and C-HSL in EPS and sludge phases, and were expected to promote the activities of BNR-related and antioxidant enzymes, and the EPS production to assist in the recovery of the impaired system's BNR performance. The QS-related BNR genera exhibited higher resilience to ZnO NPs than quorum quenching-related ones, indicating their critical role in nitrogen removal in the restored system. This work provided an insight into the potential pluripotency of AHL-based QS regulation on the ZnO NP-stressed BNR system's adaptation and recovery.
群体感应 (QS) 对纳米颗粒 (NP) 胁迫生物脱氮 (BNR) 系统的影响尚未得到充分关注。本研究系统地考察了内源性 N-酰基高丝氨酸内酯 (AHL) 为基础的 QS 调控对 BNR 系统适应氧化锌 (ZnO) NP 胁迫及其恢复潜力的贡献。虽然 1mg/L ZnO NPs 对 BNR 系统几乎没有影响，但慢性暴露于 10mg/L ZnO NPs 会抑制系统的 BNR 性能，即使在没有 NP 添加的情况下进入恢复阶段，硝化过程也会受到不可逆的损害。同时，ZnO NPs 对 AHL 和胞外聚合物 (EPS) 的产生以及超氧化物歧化酶和过氧化氢酶的活性表现出激素效应。在 ZnO NP 暴露期间，发现 C-HSL、C-HSL 和 C-HSL 与氮去除效率、紧密结合的 EPS 产生和抗氧化酶活性呈正相关。此外，Nitrospira、Dechloromonas、Aeromonas、Acinetobacter、Delftia 和 Bosea 的变化有望决定 AHL 的动态分布。在系统的恢复阶段，Dechloromonas 取代 Candidatus_Competibacter 成为主要的反硝化相关属。Dechloromonas 丰度随着水相和 EPS 相中的 C-HSL 含量以及 EPS 和污泥相中的 C-HSL 含量的增加而升高，有望促进 BNR 相关和抗氧化酶的活性以及 EPS 的产生，从而有助于恢复受损系统的 BNR 性能。与群体淬灭相关的 QS 相关 BNR 属相比，QS 相关的 BNR 属对 ZnO NPs 具有更高的弹性，表明它们在恢复系统中的氮去除中具有关键作用。这项工作深入了解了基于 AHL 的 QS 调控对 ZnO NP 胁迫 BNR 系统适应和恢复的潜在多功能性。
