Li Junlin, Ma Jiahao, Li Zhifei, Xie Jun, Zhang Yuting, Yu Mengyuan, Xia Yun, Gong Wangbao, Zhang Kai, Wang Guangjun, Zhong Quanfa, Tian Jingjing, Li Hongyan, Xie Wenping
Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, China; School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong, 510006, China; Guangdong Ecological Remediation of Aquaculture Pollution Research Center, Guangzhou, 510380, China.
Key Laboratory of Tropical and Subtropical Fishery Resource Application and Cultivation, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou, 510380, China; Guangdong Ecological Remediation of Aquaculture Pollution Research Center, Guangzhou, 510380, China.
Environ Res. 2025 Jul 21;285(Pt 2):122408. doi: 10.1016/j.envres.2025.122408.
During the centralized discharge of winter aquaculture wastewater, low temperature (≤15 °C) and low C/N ratio (≤5) result in delayed initiation of the biofilm process and decreased nitrogen removal efficiency.The quorum sensing (QS) communication system serves as the core mechanism regulating biofilm formation. This study examined how adding N-butyyl-L-homo-serine lactone (C4-HSL) affects the start-up and nitrogen removal in sequential batch biofilm reactors (SBBR) operated at 14 °C with a C/N ≤ 5. Biofilm adhesion tests showed that C4-HSL levels between 400 and 1200 ng/L notably boosted initial adhesion, peaking at 700 ng/L with a 57.5 % increase over the control. The SBBR results indicated that a high concentration of C4-HSL (700-1000 ng/L) effectively removed TN and COD, achieving a TN removal rate of 91.62 %, which was three times that of the control. C4-HSL enhances low-temperature biofilm nitrogen removal by remodeling the structure of functional microbial communities and enriching bacteria along with functional genes involved in biofilm formation and nitrification-denitrification. Additionally, C4-HSL specifically upregulated the abundance of flagella assembly and biofilm matrix synthesis genes (such as virD4, yegE) and quorum sensing-related genes (such as rpfB, bapA), promoting the secretion of extracellular polymeric substances. This drove the transition of biofilm structure from a loose state to a highly organized one, accelerating the maturation of biofilm adhesion and prolonging the stabilization period of the biofilm by 15-20 days. This study revealed the influence of C4-HSL on the initiation mechanism of low-temperature biofilm process from the perspective of quorum sensing regulation, providing a theoretical basis and technical pathway for developing aquaculture effluent treatment technologies based on quorum sensing regulation.
在冬季养殖废水集中排放期间，低温（≤15°C）和低碳氮比（≤5）导致生物膜过程启动延迟且脱氮效率降低。群体感应（QS）通讯系统是调节生物膜形成的核心机制。本研究考察了添加N-丁酰基-L-高丝氨酸内酯（C4-HSL）对在14°C、C/N≤5条件下运行的序批式生物膜反应器（SBBR）启动和脱氮的影响。生物膜附着试验表明，400至1200 ng/L的C4-HSL水平显著促进初始附着，在700 ng/L时达到峰值，比对照增加57.5%。SBBR结果表明，高浓度的C4-HSL（700 - 1000 ng/L）有效去除总氮（TN）和化学需氧量（COD），总氮去除率达到91.62%，是对照的三倍。C4-HSL通过重塑功能微生物群落结构、富集参与生物膜形成和硝化-反硝化的细菌及功能基因来增强低温生物膜脱氮。此外，C4-HSL特异性上调鞭毛组装和生物膜基质合成基因（如virD4、yegE）以及群体感应相关基因（如rpfB、bapA）的丰度，促进胞外聚合物的分泌。这促使生物膜结构从松散状态转变为高度有序状态，加速生物膜附着的成熟，并使生物膜稳定期延长15 - 20天。本研究从群体感应调控角度揭示了C4-HSL对低温生物膜过程启动机制的影响，为开发基于群体感应调控的养殖废水处理技术提供了理论依据和技术途径。
