Modification of polyacrylonitrile ultrafiltration membrane with acylase for enhanced biofouling control based on quorum quenching

Quorum sensing (QS) of bacteria can regulate biofilm development on membrane. Quorum quenching (QQ) via interfering cell-cell communication has been proven to be a novel biofouling control approach. In this study, modified polyacrylonitrile (PAN) ultrafiltration (UF) membranes were prepared by surface coating with quorumquenching acylase. The surface properties of modified membranes were characterized. The activity of acylase in modified membranes to inhibit biofilm formation was evaluated by bacterial adhesion experiments and UF tests with wastewater. Results showed that biofilm formation on modified membranes was inhibited during the culture with sewage. In UF experiments with secondary effluent as feed, the water flux decline of acylasemodified membranes was 29.4-56.9 % lower than that of unmodified membrane. In the tests with sewage as feed, the modified membranes exhibited water flux 15.2-33.5 % higher than unmodified membrane, and the flux recovery rates (FRR) were 5.6-34.6 % higher than unmodified membrane after multiple cycles of foulingcleaning tests. Analysis of the extracellular polymeric substance (EPS) in biofilm showed that the mass of protein and polysaccharide on modified membranes was reduced by 13.6-34.4 % and 3.9-12.3 %, respectively, compared to unmodified membrane. This work demonstrated the promising performance of acylase-modified UF membranes in biofouling control and the potential for water treatment applications.