Unraveling the multifaceted role of extracellular DNA (eDNA) of biofilm in bacterial physiology, biofilm formation, and matrixome architecture.

Bacterial biofilms consist of bacterial communities embedded in a self-produced extracellular matrix (EM) known as the matrixome. The matrixome primarily comprises extracellular polymeric substances (EPS) and other elements. EPS encompassing exopolysaccharides, proteins, lipids, and nucleic acids plays a key role in maintaining structural integrity and is involved in various functions. Extracellular DNA (eDNA) released into the EM through various mechanisms, including cell lysis or autolysis, membrane vesicle-mediated release, phage-mediated release, active secretion, and Type VI secretion system (T6SS)-mediated eDNA release. Quorum sensing (QS), a vital signaling system during biofilm formation, also regulates the release of eDNA in a controlled manner by coordinating gene expression in response to cell density. Once released into the EM, eDNA interacts with EPS components, enhancing matrix stability, structural cohesion, and integrity. The present review comprehends the multifaceted roles of eDNA within the biofilm matrixome, highlighting its contribution to biofilm formation, stability, and functionality through various interactions and regulatory mechanisms. It also delves into the mechanisms of eDNA release and its interactions within the biofilm matrix. Understanding these complex roles of eDNA in regulating biofilm will provide insights into developing strategies to enhance the remediation of environmental pollutants and manage biofilm-associated problems in medical settings.