Bacteriophage infectivity against Pseudomonas aeruginosa in simulated saline conditions

Seawater reverse osmosis desalination for drinking water production is renowned worldwide. As all the membrane-based technology it is heavily impacted by biofouling. Pseudomonas aeruginosa plays a key role in applications involving seawater. It forms a complex membrane biofilm matrix and, together with other sulfate reducers, it is able to produce hydrogen sulfate, a strong corrosive agent for plant structure. Common antimicrobial approaches are based on biocides, particularly chlorine, that can intact membrane integrity. Moreover, chlorine is neutralized from the RO system by the addition of sodium metabisulfite. In this study we evaluated specific bacteriophage activity against Pseudomonas aeruginosa in both planktonic state and biofilm at different temperature, pH and salinity. Bacteriophage showed good performance at a wide range of salinity and pH, while high temperature was detrimental for their replication efficacy. Finally, the best performance in membrane biofouling delaying and biofilm removal was acheived when phage therapy was combined with acid treatment. This study highlights the wide versatility of phage therapy at different environmental condition against Pseudomonas aeruginosa in both planktonic state and biofilm. In addition, this work gives important insights about the practicality of phage application integrated with the common cleaning procedure to reduce UF membrane biofouling.