Protection and consolidation of stone heritage by self-inoculation with indigenous carbonatogenic bacterial communities

Abstract

Enhanced salt weathering resulting from global warming and increasing environmental pollution is endangering the survival of stone monuments and artworks. To mitigate the effects of these deleterious processes, numerous conservation treatments have been applied that, however, show limited efficacy. Here we present a novel, environmentally friendly, bacterial self-inoculation approach for the conservation of stone, based on the isolation of an indigenous community of carbonatogenic bacteria from salt damaged stone, followed by their culture and re-application back onto the same stone. This method results in an effective consolidation and protection due to the formation of an abundant and exceptionally strong hybrid cement consisting of nanostructured bacterial CaCO3 and bacterially derived organics, and the passivating effect of bacterial exopolymeric substances (EPS) covering the substrate. The fact that the isolated and identified bacterial community is common to many stone artworks may enable worldwide application of this novel conservation methodology.

Bacterially Produced, Nacre‐Inspired Composite Materials

“…Our composite material can be deposited on‐site since its production does not require the use of complex instruments, and its chemical resistance is predicted to be comparable to that of other calcium carbonate‐based coatings, which offer excellent protection against chemical degradation and weathering. Our bacterial composites are therefore promising for applications, for example, in civil engineering for crack prevention or remediation in biocement, in CO 2 sequestration, in the automotive and aerospace industries for the production of lightweight structural components, as protective coatings for dust or erosion control, or for conservation of ornamental stone or cultural heritage items …”

Graphene‐Enhanced Nanomaterials for Wall Painting Protection

“…Carbonation process transforming Ca(OH) 2 to CaCO 3 is the crucial reason of the improved performances in flexural strength and STT . The carbonation of Ca(OH) 2 /GQD nanohybrids and two control Ca(OH) 2 materials dispersed in IPA were carried out by depositing on glass slides and storing in a humidity chamber at 23 ± 2 °C and 50 ± 5% relative humidity.…”

“…Wall paintings are the commonwealth of human beings and highly valuable to learn more about our ancestors . However, wall paintings have been facing severe damaging problems over the years, including color change due to ultraviolet (UV) irradiation (Figure S1a,b, Supporting Information), flaking phenomena (Figure S1c,d, Supporting Information) because of crystallization and dissolution of salt, hollowing (Figure S1e, Supporting Information), fungus damage, and cracks. The fact is that wall paintings are quite fragile compared with other cultural relics such as ancient metals, jades, and pottery, and it is hard to protect them compared with cultural heritage artifacts as mentioned above (Figure S2, Supporting Information) .…”

Effects of the Ionizing Radiation Disinfection Treatment on Historical Leather

“…Different bacterial colonies were isolated from leather wallpaper of Palazzo Chigi in Ariccia and identified at the molecular level by the amplification of 16S rDNA. Among them, the comparison of the obtained sequences with those held in BLAST database allowed to identify the Gram-positive Bacillus cereus, and the Gram-negative Massilia timonae, which are involved in bio-deterioration, as reported in many works (Herrera and Videla, 2004;Jroundi et al, 2017). Antibiotic susceptibility test was performed using a panel of 20 antibiotics, including inhibitors of cell wall synthesis, protein synthesis, nucleic acid synthesis, and the results are reported in Table 1.…”