New protective coatings against lampenflora growing in the Pommery Champagne cellar

Phototrophic microorganisms such as cyanobacteria and microalgae can proliferate readily in underground heritage sites where the introduction of artificial illumination equipment has significantly altered previously stable environmental conditions. The extended lampenflora biofilm growth on the bas-reliefs carved in the underground Pommery Champagne cellar in Reims (France) represents a recurring biocolonisation problem which requires periodic cleaning. The aim of this work was to limit the growth of lampenflora on chalk substrates using preventative biocidal treatments based on polyoxometalate ionic liquids (POM-ILs). Biocidal assays carried out in laboratory showed how two different colourless POM-IL coatings were more effective than commercial Preventol RI80 against two algal strains isolated from the Pommery bas reliefs, Pseudostichococcus monallantoides and Chromochloris zofingiensis. However, only one POM-IL variant was capable of sustained prevention of biofilm growth when applied to wet chalk, which replicates the more drastic natural environmental conditions of the cellar and can limit the performance of the biocidal coatings. Crucially, coating concentration studies demonstrate how POM-IL-coated slabs from previous experiments retain their biocidal activity and can prevent subsequent recolonisation following the re-inoculation of coated slabs with algae and cyanobacteria. Consequently, POM-ILs represent excellent candidates to eliminate lampenflora growth on the chalk bas-reliefs in the unique subterranean environment of the Pommery Champagne cellar.

Automated summary

Phototrophic microorganisms can easily grow in underground heritage sites, causing biofilm growth. This study aims to limit biofilm growth on chalk substrates using biocidal treatments based on POM-ILs. The experiments show that POM-IL coatings are more effective than commercial biocidal treatments and can sustain prevention of biofilm growth on wet chalk.