Effect of N-acy-l-homoserine lactones-like molecules from aerobic granules on biofilm formation by Escherichia coli K12

► Demonstration of the quorum sensing effect of aerobic granules on Escherichia coli biofilm formation. ► Granular sludge promoted E. coli biofilm formation more than activated sludge. ► Detection of N-acy-l-homoserine lactonesin (AHL) by thin-layer chromatography (TLC). ► AHL-like signal molecules produced by granules for attached growth of E. coli K12.