Biodeterioration in art: a case study of Munch's paintings

Abstract

Biocolonization and biodeterioration phenomena in Cultural Heritage is presently considered a relevant issue when planning conservation strategies and preservation measures in museum collections. Artworks such as easel paintings are source of various ecological niches for microbial communities' growth due to the presence of several organic resources. Therefore, the identification of proteinaceous materials may play an important role in the evaluation of their conservation status, in the characterisation of the artistic technique, and in the definition of compatible conservation/restoration processes. Another challenge is to understand the microbiota associated to the degradative processes when developing conservation strategies in CH artworks. For this study Edvard Munch paintings belonging to Munch Museum in Oslo presenting surface alterations were analysed to increase the knowledge about the materials used by the painter and try to understand the source and the dynamics of the associated colonising microbiota, helping in devising a conservation intervention plan. Immunoenzymatic assays was carried out in microsamples allowing the detection of casein as the binder used by the artist. The high throughput sequencing approaches allowed us to explore and characterise the microbial communities that colonise these artworks. Bacterial communities found in these artworks were mainly composed by species characterised by proteolytic capacity, an important biodeteriogenic characteristic for these paintings. Simulation assays performed in paint models prepared with casein as binder display signs of degradative action promoted by the proteolytic strains isolated from the damaged areas. This approach can be useful to promote effective intervention processes in E. Munch's paintings with the same pathologies.

Diversity and Metabolic Activity of Fungi Causing Biodeterioration of Canvas Paintings

“…The prevalence of Penicillium spp. on paintings was frequently reported [ 17 , 37 ], and the order of genera abundance is in accordance with previous studies [ 20 , 21 , 37 ]. Therefore, the fungal diversity detected in our current study is consistent with other indoor environments.…”

“…Nevertheless, canvas paintings, commonly exhibited or stored in indoor environments, are susceptible to biodeterioration too, due to their organic matter abundance. Important progress has been made in the field of canvas paintings biodeterioration, especially with respect to microbial species diversity [ 19 , 20 , 22 , 23 , 37 ]. The bacterial biodeteriorative enzymatic repertoire was occasionally examined [ 16 , 17 , 24 ].…”

“…Bacteria isolated from a canvas painting were able to solubilise Zinc white or Cobalt deep green in culture, probably due to acid-metal complexation, as a result of organic acids release during glucose metabolism [ 22 ]. Mock paintings, individually prepared with ultramarine blue or chrome yellow in casein binder and infected with proteolytic bacteria, developed structural and aesthetic alterations due to degradation of the binder layer [ 20 ]. However, the pigment degradation alone was not considered.…”

“…However, only a few studies have dealt with microbial communities inhabiting canvas paintings, especially the fungal ones [ 16 , 17 , 18 , 19 ]. Representatives of Aspergillus, Penicillium, Cladosporium, Alternaria, Bacillus are commonly found on historical canvas paintings, but the metabolites involved in the process are rarely examined [ 15 , 18 , 20 , 21 ]. The culturable fraction of the microbial diversity was successfully investigated for bacterial representatives (e.g., Microbacterium , Bacillus , Sporosarcina , Paenibacillus , Reyranella, Staphylococcus , Acinetobacter , Agrococcus ) and their biodeteriorative potential was frequently associated with the activity of endocellulases, esterases, esterase lipases, phospholipases, or proteases [ 17 , 20 , 21 , 22 ].…”

“…Representatives of Aspergillus, Penicillium, Cladosporium, Alternaria, Bacillus are commonly found on historical canvas paintings, but the metabolites involved in the process are rarely examined [ 15 , 18 , 20 , 21 ]. The culturable fraction of the microbial diversity was successfully investigated for bacterial representatives (e.g., Microbacterium , Bacillus , Sporosarcina , Paenibacillus , Reyranella, Staphylococcus , Acinetobacter , Agrococcus ) and their biodeteriorative potential was frequently associated with the activity of endocellulases, esterases, esterase lipases, phospholipases, or proteases [ 17 , 20 , 21 , 22 ]. Still, the fungal fraction is rarely recovered, and if it is successfully isolated, results in few representatives, low diversity, and limited study of their metabolic activity [ 16 , 17 ].…”