Origin and evolution of quorum quenching technology for biofouling control in MBRs for wastewater treatment

Biofouling in membrane bioreactors (MBRs), which is defined as the unwanted accumulation of microorganisms on the membrane surface, has been intensively studied for more than two decades. However, it remains a critical limiting factor to the more widespread use of MBR for wastewater treatment. The concept of quorum sensing (QS) / quorum quenching (QQ) was proposed as an anti-fouling strategy for MBRs in 2002 and the first paper on that issue was published in 2009. Since then, many studies have demonstrated and proved the potential of QQ for biofouling control in MBR through various means. The evolution of QQ-MBR has had a run of eight years in terms of QQ-microorganisms, QQ-media, and the size of the QQ-MBRs tested. This review provides an overview on the QS/QQ studies related to the elucidation and control of biofouling in MBRs, including the identification of QS signals, the isolation of QS signal producing or degrading microorganisms, and various engineering approaches to apply enzymatic or bacterial QQ in the form of QQ-media to mitigate membrane biofouling. The challenges confronting these applications and future directions of QQ-based biofouling control strategies for MBR are discussed.