Bacterial Diversity Evolution in Maya Plaster and Stone Following a Bio-Conservation Treatment
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AuthorJroundi, Fadwa; Elert, Kerstin; Ruiz-Agudo, Encarnación; González Muñoz, María Teresa; Rodríguez Navarro, Carlos Manuel
Frontiers Media SA
Maya areaBacterial diversityBioconsolidation treatmentNutritional mediumCarbonatogenic bacteriaTuff stonePlaster
Jroundi F, Elert K, Ruiz-Agudo E, Gonzalez-Muñoz MT and Rodriguez-Navarro C (2020) Bacterial Diversity Evolution in Maya Plaster and Stone Following a Bio-Conservation Treatment. Front. Microbiol. 11:599144. [doi: 10.3389/fmicb.2020.599144]
SponsorshipSantander Program, Peabody Museum (Harvard University); David Rockefeller Center for Latin American Studies (DRCLAS) at Harvard University under the "Research and Conservation of Maya Sculpture" project; Spanish Government RTI2018-099565-B-I00; Junta de Andalucía RNM-179 BIO 103; University of Granada (Unidad Científica de Excelencia) UCEPP2016-05
To overcome the limitations of traditional conservation treatments used for protection and consolidation of stone and lime mortars and plasters, mostly based on polymers or alkoxysilanes, a novel treatment based on the activation of indigenous carbonatogenic bacteria has been recently proposed and applied both in the laboratory and in situ. Despite very positive results, little is known regarding its effect on the evolution of the indigenous bacterial communities, specially under hot and humid tropical conditions where proliferation of microorganisms is favored, as it is the case of the Maya area. Here, we studied changes in bacterial diversity of severely degraded tuff stone and lime plaster at the archeological Maya site of Copan (Honduras) after treatment with the patented sterile M-3P nutritional solution. High-throughput sequencing by Illumina MiSeq technology shows significant changes in the bacterial population of the treated stones, enhancing the development of Arthrobacter, Micrococcaceae, Nocardioides, Fictibacillus, and Streptomyces, and, in one case, Rubrobacter (carved stone blocks at Structure 18). In the lime plaster, Arthrobacter, Fictibacillus, Bacillus, Agrococcus, and Microbacterium dominated after treatment. Most of these detected genera have been shown to promote calcium carbonate biomineralization, thus implying that the novel bio-conservation treatment would be effective. Remarkably, the treatment induced the reduction or complete disappearance of deleterious acid-producing bacteria such as Marmoricola or the phylum Acidobacteria. The outcome of this study demonstrates that such a bio-conservation treatment can safely and effectively be applied on temples, sculptures and stuccos of the Maya area and, likely, in other hot and humid environments.