Microbiological survey for analysis of the brown spots on the walls of the tomb of King Tutankhamun

This paper presents the preliminary findings from our investigation into the possible microbial origin of brown spots on the walls of Tutankhamun's tomb. GC/MS analysis of the brown spots indicated that they contained 16% (by weight) of malic acid, suggesting microbial involvement in their formation. However, no microbial structures associated with the brown spots were detected using scanning electron microscopy. Our observations indicate that the organism that created the spots is not active. We undertook an investigation of the current microbial communities on the walls in Tutankhamun's tomb and two other nearby tombs. There were no significant differences in the numbers or types of culturable microorganisms among the three tombs sampled. Using pyrosequencing, no statistically significant differences in community composition and structure were observed. Fungal communities were composed primarily of Penicillium whereas the abundant bacterial taxa were members of the Firmicutes, Actinobacteria and Bacteroidetes phyla. Penicillium chrysogenum isolated in this study produced malic acid in vitro, suggesting that they or other microorganisms may be responsible for the malic acid detected in the brown spots. Findings from this study were compared to those from previous studies, and a possible scenario for the formation of the brown spots was developed.

► The microbial origin of brown spots in Tutankhamun's tomb was investigated.
► GC/MS analysis revealed malic acid, a microbial metabolite, in the brown spots.
► No microbial structures were detected in the brown spots using electron microscopy.
► Penicillium was abundant in the tomb and one species produced malic acid in vitro.