Evaluation of 3D-printed nanoflower scaffolds for quorum-quenching-mediated membrane antifouling

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.

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.

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.