New species description, biomineralization processes and biocleaning applications of Roman catacombs-living bacteria

The present paper describes the great microbial diversity found on the Catacombs of St. Callistus and in particular inside the Ocean Cubiculum, CSC13. The study was part of the multidisciplinary project CATS (2000-2003) and of further monitoring campaigns carried out to understand the consequences of blue light application (2009, 2011). New species were isolated and described during the different campaigns. Further our researches point out that the stress induced by the monochromatic light while effective against phototrophic microflora, increased the number of genera with lytic activities. Some selected bacteria isolated were used to set an experimental protocol for biocleaning procedures. White patinas with biomineralization processes were associated to specific groups of bacteria such as Actinobacteria, Firmicutes and Proteobacteria.