Microbial Communities Associated with Post-Byzantine Icons: A Multi-Analytical Study

Résumé fourni par la source

Post-Byzantine portable icons are complex, multilayered heritage objects whose preservation may be influenced by interactions among their constituent materials, environmental conditions, and associated microorganisms. This study represents the first multidisciplinary investigation of this kind in Greece and examined five painted faces belonging to four post-Byzantine icons using a multidisciplinary approach combining environmental monitoring, stereomicroscopic and cross-sectional examination, Fourier transform infrared (FTIR) and micro-FTIR spectroscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS), culture-dependent microbiology, molecular identification, biofilm assessment, amplicon-based metabarcoding, and bacterial functional prediction. The results revealed substantial material and microbial heterogeneity among the examined icons and individual sampling locations. Material characterization revealed differences in the preparation layers, textile reinforcements, pigments, and surface coatings, including calcite, calcium sulfates, kaolinite, Prussian blue, Pb- and Fe-rich pigments, and HgS. Cultivable microorganisms showed variable biofilm-forming capacities. To address the minimal-sampling constraints inherent to cultural heritage objects, amplicon-based metabarcoding was used as a complementary approach to broaden microbial community characterization beyond the fraction recoverable by cultivation. Metabarcoding revealed diverse bacterial and fungal DNA signatures; however, these signatures indicate microbial association and do not, by themselves, demonstrate microbial viability, metabolic activity, or active biodeterioration. No single material- or conservation-related variable consistently explained the observed microbial patterns. Overall, the findings highlight the importance of considering microbial occurrence within the broader context of material composition, environmental conditions, and conservation state. This multidisciplinary approach provides a useful framework for contextualizing potential biological risk and supporting evidence-based preventive conservation strategies for painted wooden heritage objects.

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