Evaluation of 3D-Printed Nanoflower Scaffolds for Quorum-Quenching–Mediated Membrane Antifouling

AIMS: Recirculating aquaculture systems require high-throughput removal of pollutants during wastewater treatment, but their performance is often constrained by membrane fouling, which primarily results from the accumulation of bacterial biofilms. This study developed and evaluated a quorum quenching (QQ) strategy as an efficient and eco-friendly antifouling approach to prevent fouling of membrane modules in bioreactors. METHODS AND RESULTS: This study employed three-dimensional (3D) printing technology to immobilize a marine-derived QQ enzyme, YtnP, within an alginate matrix to fabricate QQ scaffolds designed to replace conventional feed-channel spacers in membrane modules. The physicochemical properties, durability, and antifouling performance of the resulting 3D-printed composite scaffolds were systematically evaluated. The optimal printing ink formulation comprised 0.025% purified YtnP and 11.11% sodium alginate at pH 7.2, followed by cross-linking in 2% CaCl₂ for 2 min. YtnP enzymes self-assembled and crystallized into nanoflower structures at the scaffold interface through calcium ion binding, demonstrating the role of calcium in facilitating both enzyme immobilization and alginate cross-linking. The QQ scaffolds maintained N-acyl homoserine lactone (AHL) removal efficiencies above 99.98% over nine consecutive runs and significantly suppressed biofouling on polyvinylidene fluoride (PVDF) membranes. CONCLUSIONS: The findings of this study enhance the feasibility of applying bioreactor technologies for aquaculture wastewater treatment and support the further development of recirculating aquaculture systems.