Vanillin to the rescue of filtration membranes for drinking water production

Biofouling is a phenomenon best known for affecting the hulls of boats, which the accumulation of bacterial biofilm damages if left untreated. It also threatens water filtration systems by colonizing their membranes, accelerating their ageing process. While many antibiofouling solutions are available to the marine industry, their composition often makes them incompatible with equipment designed to supply drinking water. Researchers at the Laboratoire de Génie Chimique (LGC, CNRS/Toulouse INP/Université Toulouse III - Paul Sabatier) and the Toulouse Biotechnology Institute (TBI, CNRS/INRAE/INSA Toulouse) have discovered that vanillin, the main molecule giving vanilla its aroma, is an excellent candidate for a bioinspired, biodegradable and non-toxic antibiofouling coating. They have also successfully integrated vanillin into membranes. Vanillin is already industrially produced, making it an ideal candidate for large-scale water filtration systems, as well as being inexpensive.

The formation of a bacterial biofilm requires quorum sensing, i.e. the ability of bacteria to communicate with each other, via molecular inducers, in order to know whether there are enough of them to start producing biofilm. It was already known that vanillin could block quorum sensing of certain microorganisms, but this study, published in Journal of Membrane Science, is the first to prove its efficacy at different stages of biofouling establishment, from bacterial adhesion to the surface to the production of microbial extracellular polymers. Vanillin is deposited directly on the surface of filtration membranes during filtration. Using atomic force microscopy and epifluorescence microscopy, the team demonstrated that surfaces treated in this way reduced bacterial coverage by up to 50%. Following this success with scattered bacteria, the co-authors are now working on the scale of entire biofilms.