Metagenomics-based interpretation of AHL-mediated quorum sensing in anammox biofilm reactors for low-strength wastewater treatment

AbstractAnammox-based nitrogen removal can advance sustainable wastewater treatment, including main-stream wastewater treatment. Two lab-scale anammox biofilm reactors fed with influent ammonia concentrations of 110 mg/L (Anammox-H) and 50 mg/L (Anammox-L) were operated, and nitrogen removal and mechanisms of quorum sensing (QS)/quorum quenching (QQ) were examined. The achieved nitrogen removal rates were 0.65 g N/L·d in Anammox-H and 0.25 g N/L·d in Anammox-L. Candidatus Kuenenia was dominant in both reactors. Higher contents of tight extracellular polymeric substance and hydrophobic amino acid confirmed that dense anammox biofilm developed in Anammox-H. C6-HSL and C8-HSL were detected in Anammox-H and Anammox-L, and high concentration of acyl-homoserine lactones (AHLs) in water and biomass phases of Anammox-H was consist with that more active QS processes existed in Anammox-H. Functional genes including hao, pmoA-amoC, nirK and narGZHY were detected and harbored by Candidatus Kuenenia stuttgartiensis, Nitrosomonas europaea and Lautropia sp. SCN 69-89. These organisms not only involved in nitrogen metabolism, but also in pyruvate, fatty acid and S-Adenosy-L-methionine synthesis (important for AHLs). Influent ammonia concentration influenced the balance between QQ and QS activities, resulting in different anammox activity and biomass morphology.

摘要：基于厌氧氨氧化（Anammox）的脱氮工艺可推动包括主流污水处理在内的可持续污水处理发展。本研究构建两座实验室规模厌氧氨氧化生物膜反应器，分别采用110 mg/L（Anammox-H）与50 mg/L（Anammox-L）的进水氨氮浓度进行运行，并考察了脱氮效果以及群体感应（QS）/群体淬灭（QQ）的作用机制。两座反应器的脱氮负荷分别为0.65 g N/L·d与0.25 g N/L·d。两座反应器中均以‘Candidatus Kuenenia’菌属为优势菌群。紧密胞外聚合物（tight extracellular polymeric substance）与疏水性氨基酸的含量更高，证实Anammox-H反应器中形成了更为致密的厌氧氨氧化生物膜。在Anammox-H与Anammox-L反应器中均检测到C6-高丝氨酸内酯（C6-HSL）与C8-高丝氨酸内酯（C8-HSL），且Anammox-H反应器水相与生物相中的酰基高丝氨酸内酯（AHLs）浓度更高，这与该反应器中存在更为活跃的群体感应过程相符。研究检测到hao、pmoA-amoC、nirK以及narGZHY等功能基因，这些功能基因分别携带于‘Candidatus Kuenenia stuttgartiensis’、欧洲亚硝化单胞菌（Nitrosomonas europaea）以及Lautropia属菌株SCN 69-89中。上述微生物不仅参与氮代谢过程，还参与丙酮酸、脂肪酸以及S-腺苷-L-甲硫氨酸（S-Adenosy-L-methionine）的合成，该合成途径对酰基高丝氨酸内酯的合成至关重要。进水氨氮浓度会影响群体淬灭与群体感应活性之间的平衡，进而导致厌氧氨氧化活性与生物膜形态产生差异。