The role of biotechnology in art preservation

Biocleaning on Cultural Heritage: new frontiers of microbial biotechnologies

Over the last two decades, the biotechnologies applied to Cultural heritage (CH) have become a successful novel alternative to the traditional approaches in the CH conservation and preservation. From these new perspectives, microorganisms and their metabolisms can be used for the safeguarding of artworks. Biocleaning is a field with a growing interest, based on eco-friendly processes and safe procedures, where biological reactions occurring in natural habitats are optimized in artificial conditions with the aim of CH conservation. This represents a new tool and opportunity for the development and improvement of the sector, with a great advantage for the CH conservation-restoration, in terms of safety, effectiveness, costs and environmental sustainability. This review focuses on the use of microbes and enzymes involved in biocleaning of CH artworks. The aim is to provide a comprehensive, critical and chronological view of the scientific works published until now where 'virtuous' microorganisms are applied on different CH materials, pointing out strength and drawback of the biocleaning treatments.

The Potential Use of Microorganisms as Restorative Agents: An Update

The biodeterioration process involves every type of Cultural Heritage item, including monuments, stoneworks, frescoes, and easel paintings. The accurate study of the microbial and fungal communities dwelling on artworks, and involved in their deterioration, is essential for the adoption of optimal prevention and conservation strategies. Conventional restorative methods, that usually involve chemical and physical technologies, present some disadvantages, including short-term and unsatisfactory effects, potential damage to the treated works, human toxicity, and environmental hazards. Research in the field of restoration has paved the way for innovative biological approaches, or ‘biorestoration’, in which microorganisms are not only considered as an eventual danger for artworks, but rather as potential tools for restoration. The present review describes the main aspects of the biodeterioration process and highlights the most relevant biorestoration approaches: bioconsolidation, biocleaning, biological control, and new promising bio-decontaminating compounds.

Coupling non invasive and fast sampling of proteins from work of art surfaces to surface plasmon resonance biosensing: Differential and simultaneous detection of egg components for cultural heritage diagnosis and conservation

Despite the wide application of surface plasmon resonance (SPR) to a broad area of interests, from environment to food analysis, from drug discovery to diagnostics, its exploitation in cultural heritage conservation is still unexplored. Water-based highly viscous polymeric dispersions (HVPD) composed by partially hydrolyzed polyvinyl acetate (PVA), borax, and water, were recently developed and successfully applied for the selective removal of surface degradation patinas (i.e. protein materials, natural resins etc.) from paintings of historical and artistic interest. This approach is here coupled for the first time to a SPR biosensor to simultaneously recognize albumen, yolk, or their mixtures in HVPD extracts. Ovalbumin and immunoglobulin Y are selected as analytes for egg white and yolk recognition, respectively. The biosensor was first characterized on standard analytes within the range 0-400mgL(-1) and then on fresh and dried egg albumen and yolk down to 2·10(^4) and 1·10(^5) dilution factors, respectively. Once optimized, the biosensor was combined to the HVPD application on simulated and real art samples for the evaluation of hen egg presence in the extract, i.e. albumen, yolk, or their co-presence in the matrix. For a contemporary 'sacred icon', realized by the traditional egg tempera procedure described by Cennino Cennini, the biosensor successfully distinguished different uses of egg components for the realization of painted and gilded areas, i.e. yolk and albumen, respectively. Finally, a XVIII century italian painting whose the realization technique is unknown, was tested confirming its egg tempera-based realization technique.

Fungal-Induced Deterioration of Mural Paintings: In Situ and Mock-Model Microscopy Analyses

Fungal deterioration of frescoes was studied in situ on a selected Serbian church, and on a laboratory model, utilizing standard and newly implemented microscopy techniques. Scanning electron microscopy (SEM) with energy-dispersive X-ray confirmed the limestone components of the plaster. Pigments used were identified as carbon black, green earth, iron oxide, ocher, and an ocher/cinnabar mixture. In situ microscopy, applied via a portable microscope ShuttlePix P-400R, proved very useful for detection of invisible micro-impairments and hidden, symptomless, microbial growth. SEM and optical microscopy established that observed deterioration symptoms, predominantly discoloration and pulverization of painted layers, were due to bacterial filaments and fungal hyphal penetration, and formation of a wide range of fungal structures (i.e., melanized hyphae, chlamydospores, microcolonial clusters, Cladosporium-like conidia, and Chaetomium perithecia and ascospores). The all year-round monitoring of spontaneous and induced fungal colonization of a "mock painting" in controlled laboratory conditions confirmed the decisive role of humidity level (70.18±6.91% RH) in efficient colonization of painted surfaces, as well as demonstrated increased bioreceptivity of painted surfaces to fungal colonization when plant-based adhesives (ilinocopie, murdent), compared with organic adhesives of animal origin (bone glue, egg white), are used for pigment sizing.

New Strategy for the Cleaning of Paper Artworks: A Smart Combination of Gels and Biosensors

In this work an outlook on the design and application, in the cultural heritage field, of new tools for diagnostic and cleaning use, based on biocompatible hydrogels and electrochemical sensors, is reported. The use of hydrogels is intriguing because it does not require liquid treatment that could induce damage on artworks, while electrochemical biosensors not only are easy to prepare, but also can be selective for a specific compound and therefore are suitable for monitoring the cleaning process. In the field of restoration of paper artworks, more efforts have to be done in order to know how to perform the best way for an effective restoration. Rigid Gellan gel, made up of Gellan gum and calcium acetate, was proposed as a paper cleaning treatment, and selective biosensors for substances to be removed from this gel have been obtained by choosing the appropriate enzymes to be immobilized. Using this approach, it is possible to know when the cleanup process will be completed, avoiding lengthy and sometimes unnecessary cleaning material applications.

Application of calcifying bacteria for remediation of stones and cultural heritages

Since ages, architects and artists worldwide have focused on usage of durable stones as marble and limestone for construction of beautiful and magnificent historic monuments as European Cathedrals, Roman, and Greek temples, Taj Mahal etc. But survival of these irreplaceable cultural and historical assets is in question these days due to their degradation and deterioration caused by number of biotic and abiotic factors. These causative agents have affected not only the esthetic appearance of these structures, but also lead to deterioration of their strength and durability. The present review emphasizes about different causative agents leading to deterioration and application of microbially induced calcium carbonate precipitation as a novel and potential technology for dealing with these problems. The study also sheds light on benefits of microbial carbonate binders over the traditional agents and future directions.

Applied microbiology and biotechnology in the conservation of stone cultural heritage materials

The contribution of applied microbiology and biotechnology for the preservation and restoration of culturally relevant stoneworks has been used only to a minor extent. Until recently it only involved the identification of the living organisms accountable for the deterioration of those materials by classic phenotypic identification methods. This seems to be changing, given the amount of work recently published that focuses in the introduction of molecular-based techniques for the detection of microorganisms in historic stone. Such techniques complement and expand the information up till now gathered by conventional identification methods. Along with this, efforts are being made to develop and implement bio-based methodologies that may actively contribute to the bioremediation of weathered historic stoneworks. The present mini-review aims to provide an overview of recent findings on these matters.

Biodeterioration of modern materials in contemporary collections: can biotechnology help?

Contemporary collections frequently contain man-made materials. Although synthetic materials are considered more resistant to chemical, physical and biological damage than natural materials, they can also undergo rapid deterioration. In this Opinion article, we claim that biotechnology can help to identify biodeteriogens and prevent colonisation of polymeric surfaces through the application of biological products that reduce cell adhesion. We report the study of 'Futuro', made in 1965 by the Finnish architect Matti Suuronne. This ski-cabin, constructed of glassfibre-reinforced polyester, polyester-polyurethane, and poly(methylmethacrylate), was significantly degraded by conspicuous growth of microorganisms, identified as Cyanobacteria and Archaea using fluorescent in situ hybridisation. Ultimately, if biodeteriogens are able to adhere to the polymer surfaces, molecules with enzymatic activity can help to prevent the formation of biofilms--a main cause of deterioration--and aid the work of the conservator.