Abstract
Quorum sensing is recently considered to play important roles in biological wastewater treatment processes. This study aimed to investigate diversity of N-acyl homoserine lactones (AHL) among biological wastewater treatment processes and their locations. We analyzed and quantified 10 AHL in activated sludge at wastewater treatment plants (WWTPs) by Fourier transform mass spectrometry (FTMS) and by bioassay on thin-layer chromatography (TLC). Sludge samples were taken at seven WWTPs in Japan and in Thailand, which were chosen to compare different process types including a pilot-scale membrane bioreactor process. Various AHL were detected in activated sludge, suggesting the presence of quorum sensing activity in many practical WWTPs. Detection of AHL by LC-FTMS was much more sensitive than by TLC bioassay, because TLC bioassay was implied to be affected by the presence of quorum quenching molecules in activated sludge. With LC-FTMS analysis, AHL, which has short straight chain in the acyl group, were more abundant. Especially, C4-HSL, C7-HSL, and C8-HSL were detected widely independent of locations and process types. AO processes had higher AHL productivity than other processes.
Highlights
Some microbes are known to secrete signal molecules to detect their population density, activate their group behavior when the signal molecule reaches a threshold concentration
Fourier transform mass spectrometry (FTMS), A variety of acyl homoserine lactones (AHL) were detected by LC-FTMS in all sludge samples which enables to obtain mass spectrum with very accurate (Fig. 1)
It was evidenced that various quorum sensing signal mass–charge ratios (m/z), is recently developed and applied to molecules are produced in activated sludge at practical-scale (a) C4-homoserine lactone (HSL)
Summary
Some microbes are known to secrete signal molecules to detect their population density, activate their group behavior when the signal molecule reaches a threshold concentration. This phenomenon of microbial cell-to-cell communication, known as “quorum sensing”, is recently considered to play a certain role in biological wastewater treatment processes.[1,2,3,4] Among various signal molecules reported so far, N-acyl homoserine lactones (AHL) are known to be the main signal molecules of Gram-negative bacteria. The length of acyl chain varies from 4 to 18 carbon atoms of straight chain structure or with side chain of 3-hydroxyacyl or 3-oxoacyl groups.[6,7,8,9,10,11] The various AHL are reported to trigger group behaviors, such as biofilm formation, production of extracellular polymeric substances (EPS), virulence factors, pigments, etc.[2,10,12]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
