Fungal bioleaching of mineral components in a twentieth-century illuminated parchment

Abstract

In this work, we applied scanning electron microscopy (SEM), microanalysis and Raman spectroscopy to study the fungi inhabiting a richly illuminated parchment document and the damage induced by their activity. To that aim, we collected samples of fungal mycelium from the deteriorated areas on a removable adhesive tape specifically intended for lifting fungi without damaging the support. SEM analysis of the adhesive tape samples showed the co-occurrence of several species of fungi. One strain closely resembling Acremonium species was observed only in the tape micrographs but no agar cultures were obtained. Its fungal structures showed the production of abundant oxalates with an outstanding leaching of the calcium-based materials of parchment (typically manufactured with gypsum and lime). Needle-like crystals of calcium oxalate produced by the fungus forming a uniform and quite regular grid around conidial slimy heads were documented. As a result, the areas affected by moulds were weakened, stained and characterised by a powdery patina rich in calcium. Confocal μ-Raman confirmed the presence of oxalates while EDS showed the presence of calcium in crystals. We conclude that the defacement of the parchment was due to both collagenolytic activity, and to the biotransformation of calcium-based minerals by fungi.

13C solid‐state NMR complemented by ATR‐FTIR and micro‐DSC to study modern collagen‐based material and historical leather

“…Moreover, the calcium oxalate doublet at 1,642 and 1,329 cm −1 was generally detected on grain side of these samples ( Figure S2a). The biogenic formation of calcium oxalate crystals due to fungal growth and activity was documented for parchment and CaCO 3 sized paper as reported by Pinzari et al [58,59] The broadening of resonance of peaks at 71 ppm was especially evident for HL-4 (Table 4). For samples HL-1 and HL-2, the line widths (Δν 1/2 ) were not detectable due to the overlapping with the cellulose resonances.…”

A Combined Approach to Assess the Microbial Contamination of the Archimedes Palimpsest

“…Affiliated with species of the genus Aspergillus and another 2.6 % with Acremonium charticola , a common and emerging mold pathogen in Greece (nonpublished), were 2.6 % of the sequences. Members of the genus Aspergillus [ 40 , 51 – 53 ] and Acremonium [ 52 ] have been described as active biodeteriogen agents on ancient parchments. In addition, 5.3 % of the sequences were related to Hypoxylon spp., from endophytic fungal communities of Taxus chinensis var.…”

Saprotrophic soil fungi to improve phosphorus solubilisation and release: In vitro abilities of several species

“…Studies on the potential of soil saprotrophic fungi in P release from insoluble forms in soil are still scarce and only a few species have been studied, with a predominance of Aspergillus and Penicillium species. Aspergillus niger is a very efficient organic acid producing fungus and has been described in many studies as a strong P solubiliser (Pradhan and Sukla 2006 ; El-Azouni 2008 ; Bojinova et al 2008 ; Pinzari et al 2012 ). Other fungal genera successfully tested by some authors for their phosphate solubilisation ability are Trichoderma , Mucor , Candida , Discosia , Eupenicillium, Gliocladium and some species of yeasts (Rosling et al 2007 ; Jain et al 2012 ; Saxena et al 2014 ).…”