Bacterial-Induced Calcium Carbonate Precipitation for Limestone Consolidation Under Tropical Conditions: A Sustainable Approach for Heritage Conservation

The built cultural heritage of the Maya region is severely affected by biodeterioration under tropical environmental conditions. In this study, 114 indigenous carbonatogenic bacteria were isolated from limestone collected at the Maya archaeological sites of Oxpemul and Chichén Itzá and screened through a sequential evaluation of their biomineralization and bioconsolidation potential. Biomineralization activity was detected in 83 isolates, and 22 strains exhibited more than 85% consolidation efficiency on sand and sascab, a native calcareous material. When cultivated in CCP, B4, and M-3P media, X-ray diffraction revealed the formation of calcite, aragonite, vaterite, and weddellite. Based on their overall performance, Arthrobacter sp. OX4-8C and Sphingomonas sp. CHJM-1 were selected for in situ validation. After six months of environmental exposure, treatments combining bacterial suspensions with M-3P promoted localized mineral deposition, maintained surface hardness comparable to the best-performing treatments, produced only limited chromatic changes, and showed no visible fungal colonization. These findings support the use of site-adapted indigenous bacteria as sustainable bioconsolidation agents for the conservation of limestone cultural heritage in tropical environments.