Research progress of acyl homoserine lactones (AHLs) based quorum sensing in aerobic granular sludge

Abstract:

Although the aerobic granular sludge (AGS) has the advantages of good settling property, high efficiencies of nitrogen and phosphorus removal, and better resistance to shock loads, which still faces great challenges in practical sewage treatment application due to the bottleneck of slow granulation process and easy particle disintegration. In recent years, acyl homoserine lactone (AHL)-based microbial quorum sensing (QS) has become a hotspot in this field, and it may be of great significance to the rapid formation of activated sludge and particle stabilization, including the use of AHLs can increase the secretion of extracellular polymeric substances (EPS) and to optimize the change of microbial community structure. This paper reviews the mechanism of AHLs on microorganisms, further discusses the effects of different environmental factors (including substrates, electron acceptors, sludge concentration, pH, and temperature) on AHLs, and outlines the method of adding exogenous AHLs or AHLs-secreting strains which can ultimately achieve the rapid formation and long-term stability of aerobic granular sludge. Finally, the review discusses the prospect of future research for the application of AHLs-based quorum sensing in aerobic granular sludge technology.