Live membrane filters with immobilized quorum quenching bacterial strains for anti-biofouling

Membrane filters are core materials for water treatment, reuse, and desalination. However, their fouling caused by biofilm growth is a major challenge, needing resolution. Here, we report the new strategies and efficacy of anti-biofouling membranes fabricated through the immobilization of quorum quenching (QQ) bacterial strains (Rhodococcus sp. BH4). The QQ cells are not attached to the membrane by direct phase inversion. However, they anchor to the membrane with its incubation in the presence of hydrophilic polymers (polyvinyl alcohol and alginate) as evidenced in the spectroscopic and morphological observations. Membrane filters with live QQ bacteria can degrade a signal molecule (N-octanoyl-L-homoserine lactone) with the first-order rate constant of 0.58–0.82 h⁻¹ and inhibit the growth of a biofilm-forming bacterium (PAO1) and its secretion of biopolymers. The QQ membrane demonstrates its significant anti-biofouling effect in bioreactors for treating synthetic wastewater (i.e., membrane fouling was delayed by 57–67% compared to the naked membrane), although the initial water permeabilities are reduced with surface modification by 34–47% compared to pristine condition. The findings of this work bring the broad potential for material fabrication requiring biofouling control, encountered in our daily lives and mechanical, marine, and medical industries in addition to membrane filters.