BIODETERIORATION OF PAINTS PDF
INTRODUCTION. There is now a high level of acceptance amongst biodeterioration biologists and technologists in the paints and biocides industries , that. Several paints of varying chemistry have been in use for domestic and industrial purposes. The painted Biodeterioration of domestic and public buildings. PDF | This paper presents a review of the biodeterioration of architectural paint films by bacteria, fungi and algae, concentrating on external films. references .
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According to the researchers, colonization by actinomycetes begins as soon as the sites are opened and the frescoes are excavated, becoming quite evident only 2 months after excavation and exposure to biodeterioratuon.
Unlike Bacillus pumilusgrowth and survival on mock paintings of the bacteria isolated from the fresco were not stimulated by the presence of Aspergillus niger. The group has just carried out a large statistically designed comparison, resulting in their internal publication of a Panits 5 Test Method.
The decay of the fresco was thought to have begun around the s, coincident with the establishment in the vicinity of the monastery of a series of industrial plants that emitted into the atmosphere considerable amounts of pollutants, especially sulfur dioxide.
The cave contained an impressive display of prehistoric art: Nevertheless, in a few cases attempts have been made to present a more comprehensive analysis of the different microbial groups present, to unravel the chemical modifications brought about by the microbial colonization, and to determine the succession of the microbial colonizers.
By determining which microorganisms are present at time zero, he or she pwints be able to make a reasonable assumption about how the microbial bbiodeterioration will develop. However, as the two tested species of Cladosporium did not grow on casein, masonite, or animal glue, the investigators assumed that this genus did not contribute significantly to the degradation of paintings. IBB 55, — However, if the textile was artificially aged in the laboratory by exposure to the light of a xenon lamp or to heat, treatments that result in a chemical modification of the protein, then it became susceptible also to fungal attack unpublished data.
Investigations on the presence and role of bacteria in deteriorated zones of Cozia Monastery painting.
Such results confirmed those of an earlier report on the succession of fungi on this type of paint, namely, that initially species of Aspergillusfollowed by species of Alternariaand, eventually, Aureobasidium pullulans were found. From the artificially produced areas of staining the researchers reisolated the bacterial species used for inoculation. Further, as already noticed, quite often the lists of microorganisms isolated from a damaged painting are limited to one group of microorganisms fungi, bacteria, or algae and rarely include all the microorganisms present.
Giacobini C, Firpi M. Similarly, one should try to evaluate in the laboratory how the microbial population varies when the environmental conditions change a painting on the exterior of a building will undergo colonization by microorganisms different from those colonizing a similar painting located inside the same building.
Extensive analysis of the composition of, and the variations in, the microbial population of the painted areas as well as of the unpainted rocks and the surrounding environment led to the conclusion that the population of Bracteacoccus minorresponsible for the maladie vertealso increased when the cave was closed to the public and kept in continuous darkness for long periods. Dry-Film Fungal Testing From the mid s for a period of more than ten years a large number of projects were performed.
It may be added that high levels of humidity, temperature, and light, as may be found, for instance, in warmer climates, may shorten the, one could say, life span of a painting by exacerbating the damages caused by air pollution, biological attack, and natural aging.
O’Neill T B Succession and interrelationships of microorganisms on painted surfaces. Growth of Beauvaria alba on mural paintings in Canterbury Cathedral.
Emoto Y, Miura S, editors. Cloete TE and de Bruyn EE The dominant sulphide producing bacteria, isolated from industrial cooling-water systems. These data could be taken as an indication of the presence of a fungal flora specifically developing on the painting and differing, at least in part, from that present in the environment.
Microbial Degradation of Paintings
However, it will not determine if the DNA derives from living or dead microorganisms and, more importantly, it will not allow us to distinguish between microorganisms responsible for the observed damage one could call them the parasites and those that do not contribute to it the saprophytes.
Identification of bacteria in a biodegraded wall painting by denaturing gradient gel electrophoresis of PCR-amplified gene fragments coding for 16S rRNA. In Lascaux Biodeteriofation was opened to visitors, but in it was closed indefinitely to the public.
Perusal of the lists of taxa isolated shows that the most common soil inhabitants, both fungi species of PenicilliumAspergillusCladosporiumChaetomiumand Alternaria and bacteria species of PseudomonasArthrobacterand Streptomycesare present in many of the samples analyzed.
To these damages one should add those inflicted by metabolites, often biodeteriorxtion in nature, and by extracellular enzymes excreted by microorganisms. Morton G Things that go rot in the night — a review of biodeterioration. Volume 1 – Raw Materials and Their Usage. The microbial degradation of silk: Biodeterioration and Biodegradation, 9.
Tonolo A, Giacobini C. Biodeterioration and Biodegradation 9. Saving our architectural heritage: Thus, environmental pollutants, especially sulfur dioxide and related compounds, caused direct damage to the fresco but also provided the substrates that promoted growth of aerobic and anaerobic sulfate-cycling bacteria. Gypsum deposition resulted in biodeterioratin formation of white crystal aggregates responsible for the efflorescence observed on the fresco.
This in turn could promote separation of pxints painted surface from the ground or of the ground from the masonry on which the fresco was laid. For instance, from three areas with stains of the same color, present on the same portion of a fresco, different fungi were isolated. Paintings on paper or silk are laid, in general, directly on the support, since a ground or underlay is lacking, but the pigments are kept in emulsion with organic binders.
Microbial Degradation of Paintings
The sulfuric acid produced from sulfur dioxide dissolved the calcium carbonate of the fresco, leading, eventually, to the production of a precipitate of dihydrous calcium sulfate gypsum. References Alexander M Biodegradation of chemicals of environmental concern. Bravery AF Biodeterioration of paint – a stateof- the-art review.
As aesthetic damage one must consider pigment discoloration, stains, and formation of a biofilm on the painted surface, whereas as structural damage one must consider cracking and disintegration of paint layers, formation of paint blisters, and degradation of support polymers or of glues and binders resulting in detachment of the paint layer from the support.
Their work was greatly stimulated by the finding that, after the flooding of Florence in Novembera great number of paintings, both mural and easel, were severely damaged and that the damage could be at least in part associated with the growth of microorganisms.
A microbiologist should be asked to characterize the microbial flora present on a work of art when it appears to be still in its pristine condition and well before any alteration becomes evident. Detection of fungi and mites in frescos of the monastery of St. Such differences in two frescoes painted at the same time in the same building, presumably with similar or identical materials, and restored and cleaned at the same time appear rather striking. Finally, dirt, soot, and other environmental contaminants, accumulating on the painted surface, may represent another not insignificant source of nutrients.
Thus, in general, surveys have often been limited to fungi 1810141722 — 2637475057bacteria 71832334445or cyanobacteria and eukaryotic algae 9162140 Further, in laboratory experiments, they demonstrated that treatment with fungicides could arrest or prevent microbe-induced damage to paintings. The presence of bacteria was constantly demonstrated in the samples collected from portions of the fresco disfigured by a whitish, powdery layer, whereas the absence of bacteria was demonstrated in samples from apparently undamaged portions of the fresco.
The conditions that led to the microbial bloom on the Lascaux Cave paintings probably represent an extreme case, but it may be argued convincingly that even less harsh environmental stresses than those that occurred in the less than 20 years since the opening of the Lascaux Cave may cause irreversible aesthetic and structural damage to almost any type of art work.
Paintings, whether easel or mural, contain a wide range of organic and inorganic constituents and provide different ecological niches that may be exploited by a large variety of microbial species. Whereas the population of most bacterial species remained constant or increased only slightly during the duration of the experiments, that of Pseudomonas increased linearly with the time of incubation during 12 weeks of incubation, the number of colonies of Pseudomonas spp. Rev Roum Biol Ser Bot.