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Inhibition of Biofilm Formation via Quorum Sensing on Seawater Reverse Osmosis Membranes
Edgar Napoles Gomez
Mentors: Sunny Jiang, Leda Katebian
Seawater desalination offers the potential to supplement the diminishing traditional drinking water sources
for human consumption. However, biofouling significantly reduces the flux of water through the seawater
reverse osmosis (SWRO) membranes, causing an increase in energy input for water production. SWRO
biofouling is mainly caused by marine bacterial biofilm that is regulated through bacterial communication via
quorum sensing. Quorum quenchers (QQ), molecules that block quorum sensing, may be used to disrupt
biofouling. Therefore, this study investigated the effects of two QQ identified as cinnamaldehyde, and vanillin
on four biofilm producing bacteria (B1, B2, B3, B4) formerly isolated from the Carlsbad Desalination Pilot
Plant. Vanillin or cinnamaldehyde at a concentration of 1200ppm was introduced to mixed bacterial strains in
natural seawater medium containing nutrients and incubated for 48 hours within a bio-monitoring system
containing an industrial RO membrane at a constant cross flow rate. A control was set up without the
addition of QQ. After 48 hours incubation, the RO membrane was analyzed for biofilm density formation
using a confocal laser microscope. Vanillin showed the best quorum quenching ability, reducing biofilm
density by 38.1%. Cinnamaldehyde did not show potential for quorum quenching ability and reduced biofilm
density by 4.3%. This study shows that vanillin has the potential to combat biofouling and contribute to the
development of the next generation of SWRO membranes with antifouling properties.