Parchment deteriogens

Biodeterioration of a XIII century parchment roll: new approaches for the studies and the restoration strategies

The roll parchment A.A. Arm. I-XVIII 3328, preserved in the Vatican Secret Archives, is nearly five meters long, was written in 1244 for the preliminary phase of the canonization process of the Blessed, Lorenzo Loricato. Loricato lived between XII and XIII century, he unintentionally committed a murder; for this, he withdraws for thirty years in asceticism in a cave near the monastery of Sacro Speco in Subiaco, wearing instruments of penance. However, the canonization process was unsuccessful, despite many people from Subiaco testified for miracles done by the Blessed. The roll belongs to the oldest part of the Vatican Secret Archive, the Archivum Arcis, and has been previously stored in Castel Sant'Angelo. In the roll the testimonies of miracles and life are registered and authenticated by the ‘scriniarius’, a notary of the papal chancery. Parchment were produced from animal skin and consists in the dermal skin layer. The roll parchment is mainly defaced by red or purple spots associated with localized destruction of collagen fibres, as commonly found in ancient parchments. This kind of microbial attack affected the majority of the surface of the roll, causing purple spots and flaking of the parchment, with consequent loss of ink and readability. The study and restoration of this precious document included different approaches: a physical one, to characterize the structure and conservation of the parchment; a metagenomic one, to identify the microorganisms responsible of the attack and a chemical one, to identify the composition of the purple spots. The metagenomic approach has been aimed to identify the bacterial colonizer of the purple areas by the Next Generation Sequencing (i.e. 454-pyrosequencing).

 

The integration of these approaches allowed us to identify a colonization model (in Figure) which explains why this purple stain type of deterioration is common to documents with different ages and individual stories.

The article has been published in the Nature Group Journal Scientific Reports has attracted a great media interest: online there have been over 100 articles published in 18 languages, from the oriental ones (Chinese, Japanese, Indonesian, Korean and Thai), to Russian, Galician, Brazilian, to mention only the least expected ...

 

 

The microbial community structure and composition were analysed. This work is done in collaboration with the colleagues teaching at the Master Degree in Conservation and Restoration of Cultural Heritage: Fulvio Mercuri, Department of Industrial Engineering, Silvia Orlanducci, Department of Chemistry, and Alessandro Rubechini, Vatican Secret Archives. We all are indebted to H. Exc. Most Rev. Mons. Sergio Pagano, Prefect of the Vatican Secret Archives, who gave us the unique opportunity to work in the incredible context of the Archives, among its kilometers of shelving and thousands of documents.

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Migliore L., Thaller M.C., Vendittozzi G., Mejia A.Y., Mercuri F., Orlanducci S., Rubechini A. (2017) - PURPLE SPOT DAMAGE DYNAMICS INVESTIGATED BY AN INTEGRATED APPROACH ON A 1244 A.D. PARCHMENT ROLL FROM THE SECRET VATICAN ARCHIVE. Scientific Reports, 7: 9521 DOI: 10.1038/s41598-017-05398-7

 Ancient parchments are commonly attacked by microbes, producing purple spots and detachment of the superficial layer. Neither standard cultivation nor molecular methods (DGGE) solved the issue: causative agents and colonization model are still unknown. To identify the putative causal agents, we describe the 16 S rRNA gene analysis (454-pyrosequencing) of the microbial communities colonizing a damaged parchment roll dated 1244 A.D. (A.A. Arm. I-XVIII 3328, Vatican Secret Archives). The taxa in damaged or undamaged areas of the same document were different. In the purple spots, marine halotolerant Gammaproteobacteria, mainly Vibrio, were found; these microorganisms are rare or absent in the undamaged areas. Ubiquitous and environmental microorganisms were observed in samples from both damaged and undamaged areas. Pseudonocardiales were the most common, representing the main colonizers of undamaged areas. We hypothesize a successional model of biodeterioration, based on metagenomic data and spectroscopic analysis of pigments, which help to relate the damage to a microbial agent. Furthermore, a new method (Light Transmitted Analysis) was utilized to evaluate the kind and entity of the damage to native collagen. These data give a significant advance to the knowledge in the field and open new perspectives to remediation activity on a huge amount of ancient document.


Migliore L., Vendittozzi G., Mejia A.Y., Mercuri F., Carbonetti C., Thaller M.C., Romani M., Cicero C., Orazi N., Pasqualucci A., Marinelli M., Rubechini A. (2016) - IL ROTOLO A.A., ARM. I-XVIII 3328 DELL’ARCHIVUM ARCIS: STUDI LETTERARI E SCIENTIFICI, INTERVENTI DI RESTAURO. Dall’Archivio Segreto Vaticano. Miscellanea di testi, saggi e inventari, IX: 403-421. Click here to read the article