活性污泥对硒化镉量子点暴露的胁迫响应机制  

The stress response mechanisms of activated sludge exposed to CdSe quantum dots

作　　者：杨垒[1,2] 郭淋凯 任勇翔 崔珅[1,2] 李晓彤 路颢琪 王宇超 YANG Lei;GUO Linkai;REN Yongxiang;CUI Shen;LI Xiaotong;LU Haoqi;WANG Yuchao(Shaanxi Key Laboratory of Environmental Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,China;Key Laboratory of Northwest Water Resource,Environment and Ecology,Ministry of Education,Xi′an University of Architecture and Technology,Xi′an 710055,China)

机构地区：[1]西安建筑科技大学陕西省环境工程重点实验室,西安710055 [2]西安建筑科技大学,西北水资源与环境生态教育部重点实验室,西安710055

出　　处：《环境工程学报》2023年第5期1641-1650,共10页Chinese Journal of Environmental Engineering

基　　金：陕西省自然科学基础研究计划项目(2022JM-217);陕西省教育厅专项科研项目(21JK0716)。

摘　　要：为揭示硒化镉(CdSe)量子点(quantum dots,QDs)在复杂环境体系中的生物毒性效应,本研究以活性污泥为研究对象,探讨了CdSe QDs(0.1~10 mg·L^(-1))长期暴露对序批式活性污泥反应器运行效能、污泥性能以及微生物代谢作用的影响。结果表明,在实验质量浓度范围内,出水COD值和硝酸盐波动较大,而硝化作用影响较小,且低剂量CdSe QDs的存在加速了NH_(4)^(+)-N的降解,1 mg·L^(-1)CdSe QDs将平均氨氧化速率由2.2 mg·(L·h)^(-1)提高到3.3 mg·(L·h)^(-1)。尽管CdSe QDs会引起出水浊度略微增加,但污泥沉降性能始终维持稳定。CdSe QDs主要与污泥表面的C—O—C、C—O、C—C和磷酸基团结合,诱导胞外聚合物的酪氨酸类蛋白荧光淬灭。同时,微生物会通过分泌色氨酸类蛋白以缓解胁迫影响。此外,活性污泥的物种丰富度和多样性均受CdSe QDs的抑制,但低质量浓度CdSe QDs有利于Nitrospirae相对丰度的增加。PICRUSt2预测显示,微生物的新陈代谢和遗传信息处理相关的代谢通路均受到CdSe QDs的显著抑制,膜传输和信号传导的代谢通路丰度最终分别下降至32552和7876,导致反应器出水COD值随暴露剂量的增加而逐渐增大。因此,CdSe QDs通过改变微生物群落结构和功能影响活性污泥有机物的去除效果,但对硝化反应及污泥絮凝和沉淀性能并未表现出明显负面效果。In order to reveal the biotoxicity of CdSe quantum dots(QDs)in complex environmental systems,activated sludge was taken as the research object to study the effects of long-term exposure to CdSe QDs(0.1~10 mg·L^(−1))on the operation efficiency,sludge performance and microbial metabolism in sequencing batch reactor(SBR).The results showed that COD and nitrate concentrations in effluent fluctuated greatly under the stress of CdSe QDs(0.1~10 mg·L^(−1)),but nitrification performance was stable.Low dosed CdSe QDs accelerated degradation of NH_(4)^(+)-N,and 1 mg·L^(−1)CdSe QDs could increase average oxidation rate of NH_(4)^(+)-N from 2.2 to 3.3 mg·(L∙h)^(−1).Although CdSe QDs caused a slight increase in effluent turbidity,the sludge sedimentation maintained stable.CdSe QDs mainly bound to C—O—C,C—O,C—C and phosphate group on sludge surface,and caused the fluorescence quenching of tyrosine-like protein in extracellular polymeric substance.Meanwhile,microorganisms also secreted tryptophan-like proteins to alleviate stress.Besides,both abundance and diversity of microbes in activated sludge were inhibited by CdSe QDs,but low level CdSe QDs were conducive to abundance of Nitrospirae.The results predicted by PICRUSt found that the metabolic pathway for metabolism and genetic information processing was significantly inhibited by CdSe QDs,and the abundances of the metabolic pathway for membrane transport and signal transduction finally decreased to 32552 and to 7876,respectively.That might be the reason for the increase in effluent COD with the rise of exposure dosage.Therefore,CdSe QDs affected the organic matter removal by changing the structure and function of microbial community in activated sludge,but showed no obvious negative effects on nitrification,sludge settling and flocculation.

关 键 词：硒化镉量子点 活性污泥 生物硝化 胞外聚合物 微生物群落 

分 类 号：X703[环境科学与工程—环境工程]