Pseudonocardia in white colonizations in two caves with Paleolithic paintings

Deterioration caused by microbial colonization is one of the factors affecting the conservation of Paleolithic paintings in caves. Assessing the composition of the microbial communities represents the first stage in understanding and controlling these colonizations. The microbial communities of the Cave of Doña Trinidad (Ardales, Malaga, Southern Spain) and Santimamiñe (Kortézubi, Biscay, Northern Spain) were analyzed by molecular techniques based on RNA and DNA. Microbial community fingerprints obtained by denaturing gradient gel electrophoresis and 16S rRNA gene libraries and sequencing detected that the major constituents were Actinobacteria belonging to the genus Pseudonocardia. Unlike previous reports on different caves, this study confirms the highly significant role of Actinobacteria as metabolically active microorganisms in the biodeterioration of subterranean environments.