title: Biofilm activity and sludge characteristics affected by exogenous N-acyl homoserine lactones in biofilm reactors.
abstract: This study verified the effect of N-acyl homoserine lactone (AHL) concentrations on mature biofilm systems. Three concentrations of an AHL mixture were used in the batch test. Introducing of 5nM AHLs significantly increased biofilm activity and increased sludge characteristics, which resulted in better pollutant removal performance, whereas exogenous 50nM and 500nM AHLs limited pollutant removal, especially COD and nitrogen removal. To further identify how exogenous signal molecular affects biofilm system nitrogen removal, analyzing of nitrifying bacteria through real-time polymerase chain reaction (RT-PCR) revealed that these additional signal molecules affect nitrifying to total bacteria ratio. In addition, the running state of the system was stable during 15days of operation without an AHL dose, which suggests that the changes in the system due to AHL are irreversible.
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, China.
authors.forename: Huizhi
authors.initials: H
authors.lastname: Hu
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, China. Electronic address: junguohe@263.net.
authors.forename: Junguo
authors.initials: J
authors.lastname: He
authors.affiliation: Central and Southern China Municipal Engineering Design and Research Institute Co., Ltd., 41 Jiefang Park Road, Wuhan, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, China.
authors.forename: Huarong
authors.initials: H
authors.lastname: Yu
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
mesh_terms: D054742:Acyl-Butyrolactones / Q000494:pharmacology*; D001419:Bacteria; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D019149:Bioreactors; D002851:Chromatography, High Pressure Liquid; D058465:Nitrification; D009584:Nitrogen / Q000378:metabolism*; D053038:Quorum Sensing; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D053719:Tandem Mass Spectrometry; D018505:Waste Management / Q000379:methods
chemical_list: D054742:Acyl-Butyrolactones; D012722:Sewage; D009584:Nitrogen
keywords: Biofilm activity; Exogenous AHLs; Extracellular polymeric substances; Nitrifying bacteria; Sludge characteristics