Antifungal activity of some plant extracts and essential oils against fungi-infested organic archaeological artefacts

The determination of the antifungal activities of nine kinds of powdered plant extracts and five essential oils was studied in vitro against four of the most common fungal species (Aspergillus flavus, A. versicolor, Penicillium sp. and P. purpurogenum), which were isolated from different organic materials from archaeological artefacts such as papyrus and linen. The essential oils showed greater efficacy than the powdered plant extracts, where thyme and lemongrass oils were the most potent. Also, the minimum inhibitory concentration and minimum fungicidal concentration of these oils were determined. Furthermore, their chemical components were identified using gas chromatography-mass spectrometry (GC-MS) analysis. In vivo, studies were performed using biodeteriorated samples for applying treatment, in which the microbiological test revealed that both oils can eradicate both tested fungi completely after exposure time, ranging from two weeks for papyrus samples to 14 weeks for linen. A scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and colorimeter were used to assess the treatment process, leading to the final results, which suggest that the essential oils could be useful sources of fungicidal preparations for the disinfection of biodeteriorated linen and papyrus artefacts. Nevertheless, further studies are strongly recommended to introduce these sources into practical use in preventive conservation.     

Mold-deteriorated archaeological Egyptian papyri: Biodeteriogens,monitoring the deterioration,and treatment approach

Fungi play a critical role in the deterioration of ancient papyri due to their organic and hygroscopic nature. Fourteen fungal species belonging to five genera—Aspergillus, Cladosporium, Penicillium, Talaromyces, and Ulocladium—were isolated and identified from 20 Egyptian papyrus artifacts located at the Grand Egyptian Museum—Conservation Center (GEM-CC). The biodeterioration mechanism was evaluated by two analyses: cellulase enzyme activity and acid production assay. The isolated fungus P. lanosum showed potent biodeterioration power as it exhibited the highest enzymatic activity and could produce acid as well. Four different analyses were performed to assess the entity of the biodeterioration phenomenon: scanning electron microscopy, Fourier transform infrared spectroscopy, colorimetry, and pH measurements. The analyses demonstrated considerable changes in surface morphology, chemical structure (mainly represented by oxidation and hydrolysis of infected papyrus samples), darkness of the papyrus samples (ΔE 3.84–7.33), and pH (which dropped to 5.2 in the case of A. niger-infected sample. This article builds a preliminary perception for monitoring the biodeterioration of archaeological papyri and a trial for in vitro treatment to prevent further degradation, which may lead to loss of our valuable artifacts over a prolonged period.