A contribution to understand the Portuguese emblematic Anca limestone bioreceptivity to fungal colonization and biodeterioration

Fungal deteriorative action on historical stone objects often leads to important and incalculable cultural heritage losses. The An & ccedil;& atilde; stone is a unique limestone type widely used in some of the most impor-tant and emblematic Portuguese monuments. Being a soft and porous calcium carbonate limestone, this substrate is known to have a significant bioreceptivity to microbial colonization often resulting in noto-rious biodeterioration. Nonetheless, fungal bioreceptivity and biodeterioration of this lithotype remains scarcely characterized. With this in mind, the main aims of this work were to evaluate these aspects in a controlled laboratory environment. Inoculation of several fungal species in stone replicas revealed that Penicillia growth occupied larger areas under rich micro-nutrient environments, while Aspergilli and the black fungal species Aeminium ludgeri only denoted a slightly more accentuated growth under depleted nutrient conditions. Moreover, all species produced noticeable aesthetic alterations. In addition, we were able to verify A. ludgeri endolithic growth, Aspergillus glaucus putative hyphae penetration into calcite lay-ers and mineralization phenomena occurring around A. westerdijkiae hyphae. By itself, this study provides a key update regarding fungal biodeterioration of this ancient, emblematic and remarkable limestone. (c) 2021 Elsevier Masson SAS. All rights reserved.

Automated summary

This study evaluated the growth of different fungi on stone replicas and found that different fungi performed differently under different nutrient environments. In addition, aesthetic alterations caused by fungal growth, as well as possible erosion and mineralization phenomena of calcite layers by fungi, were observed.