Biodeterioration of Glass-Based Historical Building Materials: An Overview of the Heritage Literature from the 21st Century

Fungal biodeterioration and preservation of cultural heritage, artwork, and historical artifacts: extremophily and adaptation

SUMMARYFungi are ubiquitous and important biosphere inhabitants, and their abilities to decompose, degrade, and otherwise transform a massive range of organic and inorganic substances, including plant organic matter, rocks, and minerals, underpin their major significance as biodeteriogens in the built environment and of cultural heritage. Fungi are often the most obvious agents of cultural heritage biodeterioration with effects ranging from discoloration, staining, and biofouling to destruction of building components, historical artifacts, and artwork. Sporulation, morphological adaptations, and the explorative penetrative lifestyle of filamentous fungi enable efficient dispersal and colonization of solid substrates, while many species are able to withstand environmental stress factors such as desiccation, ultra-violet radiation, salinity, and potentially toxic organic and inorganic substances. Many can grow under nutrient-limited conditions, and many produce resistant cell forms that can survive through long periods of adverse conditions. The fungal lifestyle and chemoorganotrophic metabolism therefore enable adaptation and success in the frequently encountered extremophilic conditions that are associated with indoor and outdoor cultural heritage. Apart from free-living fungi, lichens are a fungal growth form and ubiquitous pioneer colonizers and biodeteriogens of outdoor materials, especially stone- and mineral-based building components. This article surveys the roles and significance of fungi in the biodeterioration of cultural heritage, with reference to the mechanisms involved and in relation to the range of substances encountered, as well as the methods by which fungal biodeterioration can be assessed and combated, and how certain fungal processes may be utilized in bioprotection.

Non-destructive 3D exploration of silicate glass corrosion: a combined multiscale approach from the macro to the nanoscale

In this research, a comprehensive multi-technique analysis, including synchrotron-based X-ray micro-computed tomography, is used to visualize the microstructure of alteration in a very particular Roman glass fragment, in which millennia of corrosion history have not significantly impacted the integrity of the fragment itself. This exceptionally rare occurrence has allowed for the maximization of meaningful data acquisition, by examining the alteration structures from the macro to the nanoscale. This study elucidates the intricate mechanisms underlying glass corrosion when in contact with soil, providing quantitative data and phase correlations in the alteration structures. These findings validate and refine existing predictive corrosion models.

From Biodeterioration to Creativity: Bioreceptivity of Spruce Pine 87 Glass Batch by Fungi

The bioreceptivity, and the consequent biodeterioration of contemporary glass, used by artists worldwide, was studied. The two main objectives were: first, to verify if fungi with some culture media would produce more damages than the same fungi without a nutritional source, and to verify if the two genera of fungi produce the same damage on the same glass. Colourless glass samples with Spruce Pine 87 Batch (SPB-87) composition were inoculated with two distinct fungal species, Penicillium chrysogenum and Aspergillus niger, separately: (i) half with fungal spores (simulating primary bioreceptivity), and (ii) half with fungi in a small portion of culture media (simulating organic matter that can be deposited on exposed glassworks, i.e., secondary bioreceptivity). The alteration of glass surfaces were analysed by Optical Microscopy, SEM-EDS and µ-Raman. The mycelium of Penicillium chrysogenum generated a higher amount of fingerprints, stains and iridescence, whereas Aspergillus niger produced more biopitting and crystals on the glass surface. However, both species damaged the glass to different degrees in 4 and 6 months after the inoculation, producing physico-chemical damage (e.g., iridescence, biopitting), and chemical alterations (e.g., depletion and deposition of elements and crystals). The primary bioreceptivity experiment of glass samples inoculated with Aspergillus niger results in less damage than in the case of secondary bioreceptivity, being almost similar for Penicillium chrysogenum. The new and in-depth understanding of the bioreceptivity and deterioration of post-modern glass art and cultural heritage provided here is of paramount importance for the scientific, conservation and artistic communities – to protect glass cultural materials, or seen by artists as innovative and inspirational ways of creating glass art in the future.

Application of Biology to Cultural Heritage

This Special Issue of the Applied Sciences, entitled “Application of Biology to Cultural Heritage” aimed to cover all the latest outstanding progress of biological and biochemical methods developed and applied to cultural heritage [...]