Quorum sensing enhances interspecies electron transport in biological wastewater treatment: Insights from molecular mechanisms and enhancement strategies

Microbial communication between cells occurs mainly through the release and reception of quorum sensing (QS) molecules, which play an important role in microbial communities and have been extensively studied. Evidence indicates that QS signals do not serve as redox shuttles themselves, but rather regulate the synthesis of electron shuttling molecules. However, the biological mechanisms by which QS enhances interspecies electron transport remain an area of emerging research. This review focuses on how QS regulates the molecular mechanisms underlying interspecies electron transport in biological wastewater treatment. The first step is to examine the structural characteristics of QS signaling molecules, which shows that the synthesis of Autoinducer-2 is not exclusive to a single bacteria species. Rather, it is believed to occur within interspecific communities. These findings highlight potential mechanisms through which QS facilitates the generation of extracellular polymeric substances (EPS). Indirect extracellular electron transfer is facilitated by electron shuttles; in this realm, EPS encompass a variety of redox-active compounds, including free riboflavin and c-type cytochromes. These can enhance extracellular electron transfer performance. Additionally, the paper emphasizes the strategies by which QS enhances electron transport during wastewater treatment. It discusses factors influencing QS, the role of exogenous signaling molecules, the establishment of artificial microbial communities, and the integration of conductive materials. The paper identifies existing knowledge gaps and potential opportunities for further research. This review provides a perspective on developing effective and pragmatic strategies to enhance interspecies electron transport. This may improve the performance of biological wastewater treatment and expand the application of QS in environmental remediation.