Perspectives on adhesion and irreversible fouling to delineate mitigation effects of autoinducer-2 mediated quorum quenching on biofouling

This study systematically investigated the effect of interfering with autoinducer-2 (AI-2) signaling system on controlling initial fouling attachment and irreversible components. Exposure of bacteria to the inhibitor significantly reduced the expression of the luxS gene, which resulted in a 37.3% reduction of AI-2 signaling molecule synthesis. Expression of flagellin and kinesin, which determine bacteria adhesion properties, and virulence genes was significantly down-regulated. AI-2 quorum quenching (QQ) significantly suppressed the initial biofilm growth and inhibition efficiency was positively correlated with bacteria concentration. Extracellular polymeric substances accumulation decreased by 40.8% in QQ experiment relative to the control, thus mitigating the flux decline. Polysaccharides, which constitute irreversible components, were significantly reduced by 69.3% with presence of inhibitor. AI-2 QQ altered protein and peptide structure of fouling layer, which converted irreversible fouling into reversible fouling. These findings contributed to the understanding of QQ susceptibility to initial fouling, providing a theoretical basis for engineering applications.