Influence and mechanism of N-(3-oxooxtanoyl)-L-homoserine lactone (C8-oxo-HSL) on biofilm behaviors at early stage

N-acyl-homoserines quenching, enzymatic quenching of bacterial quorum sensing, has recently applied to mitigate biofilm in membrane bioreactor. However, the effect of AHLs on the behavior of biofilm formation is still sparse. In this study, Pseudomonas aeruginosa biofilm was formed on ultra-filtration membrane under a series of N-(3-oxooxtanoyl)-L-homoserine lactone (C-8-oxo-HSL) concentrations. Diffusing C-8-oxo-HSL increased the growth rate of cells on biofilm where the concentration of C-8-oxo-HSL was over 10(-7) g/L. The C-8-oxo-HSL gradient had no observable influence on cell density and extracellular polymeric substances of biofilm with over 10(-7) g/L C-8-oxo-HSL. Surprisingly, 10(-11)-10(-8) g/L of C-8-oxo-HSL had no effect on cell growth in liquid culture. The cell analysis demonstrated that the quorum sensing system might enhance the growth of neighboring cells in contact with surfaces into biofilm and may influence the structure and organization of biofilm.