Bacterial Communities in Pigmented Biofilms Formed on the Sandstone Bas-Relief Walls of the Bayon Temple, Angkor Thom, Cambodia

• Published in: Microbes and Environments Vol. 28; no. 4; pp. 422 - 431
• Main Authors: Kusumi, Asako, Li, Xianshu, Osuga, Yu, Kawashima, Arata, Gu, Ji-Dong, Nasu, Masao, Katayama, Yoko
• Format: Journal Article
• Language: English
• Published: Japan Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles 2013; Japan Science and Technology Agency; Japanese Society of Microbial Ecology/The Japanese Society of Soil Microbiology
• Subjects: Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; bacterial community; Bacterial Physiological Phenomena; biodeterioration; Biofilms; Cambodia; cultural heritage; Culture; denaturing gradient gel electrophoresis; Geologic Sediments - microbiology; History, Ancient; Molecular Sequence Data; non-destructive sampling; Phylogeny; Religion - history; Salmon; Sandstone; Tropical environments; Cambodia
• ISSN: 1342-6311; 1347-4405
• DOI: 10.1264/jsme2.ME13033

The Bayon temple in Angkor Thom, Cambodia has shown serious deterioration and is subject to the formation of various pigmented biofilms. Because biofilms are damaging the bas-reliefs, low reliefs engraved on the surface of sandstone, information about the microbial community within them is indispensable to control biofilm colonization. PCR-denaturing gradient gel electrophoresis (DGGE) analysis of biofilm samples from the pigmented sandstone surfaces showed that the bacterial community members in the biofilms differed clearly from those in the air and had low sequence similarity to database sequences. Non-destructive sampling of biofilm revealed novel bacterial groups of predominantly Rubrobacter in salmon pink biofilm, Cyanobacteria in chrome green biofilm, Cyanobacteria and Chloroflexi in signal violet biofilm, Chloroflexi in black gray biofilm, and Deinococcus-Thermus, Cyanobacteria, and Rubrobacter in blue green biofilm. Serial peeling-off of a thick biofilm by layers with adhesive sheets revealed a stratified structure: the blue–green biofilm, around which there was serious deterioration, was very rich in Cyanobacteria near the surface and Chloroflexi in deep layer below. Nitrate ion concentrations were high in the blue–green biofilm. The characteristic distribution of bacteria at different biofilm depths provides valuable information on not only the biofilm formation process but also the sandstone weathering process in the tropics.