Prevention of bacterial adhesion in water conduction systems using vanillin-functionalized grates

Pathogenic microorganisms can adhere to the surfaces of water conducting systems, finally resulting in biofilm structures. Considering the importance of the adhesion capability of cells and the biofilm formation in these surfaces, their inhibition by using naturally occurring antimicrobial compounds can be a potential alternative or complement to water chlorination. This work aimed to study the antiadhesive capability of vanillin-functionalized stainless-steel surfaces against bacteria present in low-pressure water distribution network. Stainless-steel surfaces were pretreated (by sanding or polishing) and activated, allowing the covalent anchoring of vanillin to the stainless-steel. Characterization of functionalized surfaces, by macroscopic, microscopic, and elemental analysis confirmed the efficiency of the vanillin anchoring protocol. Subsequently, in vitro antiadhesive capability assays were performed with Staphylococcus epidermidis as a model microorganism to assess the antiadhesiveness capacity of the functionalized surfaces. This assay allowed the confirmation of the capacity of vanillin-functionalized surfaces to prevent the adhesion of S. epidermidis to the stainless-steel surfaces. Finally, grates were functionalized and placed in low-pressure water conduction pipes in the city of Valencia, Spain. After placement, samples of the biofilm adhered to the grates were taken at certain times and analyzed through metagenomic analysis. The results showed statistically significant differences in both the amount and type of bacterial strains adhered to vanillin-functionalized and non-functionalized grates. These findings demonstrated for the first time the potential application of vanillin-functionalized stainless-steel surfaces in water conduction systems to avoid the adhesive ability of bacteria, preventing their contamination and/or biofilm formation. [Display omitted] •Vanillin-functionalization inhibits adhesion of S. epidermidis to stainless steel surfaces.•Functionalized grates reduced biofilm variability and bacterial concentration.•The effect of functionalization is highly dependent on the bacterial genus.•Vanillin enhances stainless-steel grates' anti-biofilm properties in water networks.