Diversity and activities of pioneer bacteria, algae, and fungi colonizing ceramic roof tiles during the first year of outdoor exposure

Like other building materials, ceramic roof tiles are biodeteriorated over time. Natural conditions affect deterioration processes, but the development of a biofilm composed many types microorganisms also plays critical role in biodeterioration. However, pioneering stages formation remain poorly studied, whereas they determine well-characterized mature biofilms. To further characterize this microbial diversity, bacterial, algal, and fungal colonization new exposed to outdoor one full year was monitored, combining fluorimetry, imaging (SEM, confocal macroscopy), culture-based, high-throughput sequencing approaches. For all samples, biofilms were found be extremely diverse dominated by Actinobacteria (Pantoea sp. - up 90% bacterial diversity -, Pseudomonas -up 75%-), Chlorophyta (Trebouxiophyceae -100% algal diversity-), Pleosporales (Alternaria 75% diversity-). Interestingly, if highly heterogeneous between exposition sites, patterns succession remained comparable regardless tile type exposure site. Additionally, we investigated whether isolates collected study harbor some physiological traits related their pioneer character. This work revealed that organisms colonizing harbored interesting features like ability produce matrix anti-quorum sensing antimicrobial compounds, highlighting intense competition players during priming colonization. Altogether, our results emphasize necessity taxonomically functionally key involved design innovative antifouling solutions for tiles.