Built Cultural Heritage Microbiome: exploring the composition and metabolic activity of the bacterial and fungal communities of white marble of Florence Cathedral

Stone-built cultural heritage exposed to urban environment is a habitat where heterogeneous microbial communities grow, inducing significant biodeterioration. The investigation of microbial communities' composition and their metabolic activity is essential to take the most appropriate measures to control their harmful growth. The conservation of the Cathedral of Santa Maria del Fiore in Florence is a main issue of worldwide concern. Here we investigate the microbiota inhabiting the external white marbles of Florence Cathedral in two differently exposed areas where dark discoloration is a widespread deterioration phenomenon. .DNA metabarcoding of the 16S rRNA gene and ITS region was used to investigate the bacterial and fungal, respectively.. Furthermore, the entire microbial community was analyzed for its metabolic activity through Biolog Ecoplates technology.The evidenced a different structure of the communities of the two study sites. The higher concentration of some bacterial and fungal taxa in the South-East area could be correlated to the higher metabolic potential of the community found.