Degradation of ancient Maya carved tuff stone at Copan and its bacterial bioconservation

Researchers have identified a novel bioconservation method that effectively stabilizes ancient Maya tuff stone at Copan, addressing significant degradation issues caused by humidity-induced clay swelling and microbial weathering. Traditional consolidants, such as polymer- and alkoxysilane-based treatments, have proven ineffective in preventing this damage. The study demonstrates that applying a sterile nutritional solution activates indigenous bacteria to produce calcium carbonate biocement, which strengthens the stone matrix while reducing clay swelling due to bacterial exopolymeric substances (EPS). This environmentally friendly approach not only preserves fragile stones but also imparts hydrophobicity, making it a promising solution for tropical conditions. The findings open new avenues for conservation efforts in UNESCO World Heritage Sites like Copan and similar regions.

Elert, K., Ruiz-Agudo, E., Jroundi, F., Gonzalez-Muñoz, M. T., Fash, B. W., Fash, W. L., Valentin, N., de Tagle, A., & Rodriguez-Navarro, C. (2021). Degradation of ancient Maya carved tuff stone at Copan and its bacterial bioconservation. Npj Materials Degradation, 5(1). https://doi.org/10.1038/s41529-021-00191-4