title: Quorum quenching is responsible for the underestimated quorum sensing effects in biological wastewater treatment reactors.
abstract: Quorum sensing (QS) and quorum quenching (QQ) are two antagonistic processes coexisting in various bacterial communities in bioreactors, e.g., activated sludge for biological wastewater treatment. Although QS signal molecules are detected in activated sludge reactors and known to affect sludge properties and reactor performance, there has been no direct evidence to prove the endogenous existence of QQ effects in activated sludge. In this study, for the first time, acyl homoserine lactones-degrading enzymatic activity, a typical QQ effect, was discovered in activated sludge and found to considerably affect the QS detection results. The coexistence of QS and QQ bacteria in activated sludge was further confirmed by bacterial screening and denaturing gradient gel electrophoresis analysis. The method developed in this study could also be used to evaluate QQ activities in bioreactors, and a possible way is provided to tune bioreactor performance through balancing the QS and QQ processes.
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Xiang-Ning
authors.initials: XN
authors.lastname: Song
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China. Electronic address: chengyy@mail.ustc.edu.cn.
authors.forename: Yuan-Yuan
authors.initials: YY
authors.lastname: Cheng
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Wen-Wei
authors.initials: WW
authors.lastname: Li
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Bing-Bing
authors.initials: BB
authors.lastname: Li
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Sheng
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Cai-Yun
authors.initials: CY
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China.
authors.forename: Yun-Kun
authors.initials: YK
authors.lastname: Wang
authors.affiliation: Environmental Engineering Research Centre, Department of Civil Engineering, The University of Hong Kong, Hong Kong.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Li
authors.affiliation: CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei 230026, China. Electronic address: hqyu@ustc.edu.cn.
authors.forename: Han-Qing
authors.initials: HQ
authors.lastname: Yu
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism; D019149:Bioreactors; D058645:Denaturing Gradient Gel Electrophoresis; D018613:Microscopy, Confocal; D015394:Molecular Structure; D053038:Quorum Sensing / Q000502:physiology*; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D054742:Acyl-Butyrolactones; D012722:Sewage
keywords: AHL-degrading enzymes; Activated sludge; Acyl homoserine lactones (AHL); Quorum quenching; Quorum sensing