Assessment of acid mist on mortar biodeterioration simulating the wall of Jardim da Princesa, the National Museum of Rio de Janeiro, Brazil

This work aimed to evaluate the effect of acid mist on microbial communities developed on mortar with same composition from the wall of the National Museum in Rio de Janeiro. Five autochthonous microbial groups were inoculated on coated with acrylic paint and uncoated mortar surfaces and submitted to acid mist or water mist for 100 days. A heterogeneous biofilm was well developed in uncoated coupons under acid mist. Molecular analysis revealed that the bacterial communities were structured according to the incubation condition. The impact of coating on bacterial community structure was more important than the acid mist effect. The eukaryotic community structure was not affected by the acid mist, whereas the impact of coating by paint has been observed. The alpha diversity indexes also varied according to the treatment. H’ and D were higher for uncoated conditions, particularly when submitted to acid mist. Actinobacteria, Chloroflexi, Cyanobacteria, Firmicutes and Proteobacteria were dominant. Additionally, eukaryotic community was not affected by the acid mist and paint and Tremellomycetes dominated. [Display omitted] •Evaluation of coating and acid mist in the mortar biodeterioration.•Experimental ecology, culture and molecular biology, and imagery provided good tools.•Acid mist promotes the development of microorganisms.•Bacterial and fungal communities were impacted by coating.