Potential Application of D-Amino Acids in Biofouling Control of Nanofiltration (NF) Membranes

Biofouling is a major impediment for the application of reverse osmosis filtration and nanofiltration in water and wastewater treatment as well as seawater desalination. In this study, a novel biofouling control strategy of using D-amino acids to interfere with biofilm formation was evaluated. Impact of D-amino acids on the surface attachment and biofilm formation of Pseudomonas aeruginosa was investigated in batch and continuous flow filtration systems. All 19 D-amino acids demonstrated inhibitive effects on P. aeruginosa biofilm formation. In particular, D-tyrosine was found to strongly inhibit P. aeruginosa attachment and biofilm formation on an NF membrane. When continuously supplemented to the membrane feed water in a bench scale nanofiltration system, it prohibited irreversible biofouling of the NF membrane at concentrations as low as 3 μM. The effectiveness of biofilm control by these D-amino acids seems to strongly depend on the ratio of D-amino acid concentration to bacterial cell number