Control of sludge microbial biofilm by novel quorum quenching bacteria Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 encapsulated sodium alginate - Magnetic iron nanocomposites

Biofouling control via quorum quenching (QQ) approach is becoming popular among other fouling mitigation strategies. In the present study, the mitigation of membrane biofouling problem via disruption of cell-to-cell communication was studied by immobilizing QQ bacteria in sodium alginate magnetic nanocomposite beads. Two QQ bacteria viz. Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 isolated from dairy waste activated sludge was immobilized individually into the beads. Scanning electron microscopy (SEM) analysis revealed the successful immobilization of QQ bacteria into the alginate nanoparticle beads. The Confocal laser scanning microscopy (CLSM) results provided evidence of biofouling controlled activities of Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 immobilized nanocomposite (IMN) beads. Further, the membranes incubated with Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 IMN beads showed better flux (19% and 22% higher, respectively) than the control. Hence, the results revealed that the QQ bacteria IMN beads would be an efficient approach for controlling the biofilm developed on the cellulose acetate membrane surface.