Biocleaning of Dammar Varnish from Easel Paintings: An Experimental Preliminary Approach
[EN] Aged varnish layers distort the original appearance or integrity of easel paintings and they must be removed in most cases. Toxic solvents (harmful to conservators, the artwork and the environment) are frequently used. To seek an alternative to these harmful products, here we assay the use of s...
| Authors: | , , , |
|---|---|
| Format: | article |
| Publication Date: | 2025 |
| Country: | España |
| Institution: | Universitat Politècnica de València (UPV) |
| Repository: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Language: | English |
| OAI Identifier: | oai:dnet:riunet______::0aab3f7c2d8ddb15dd34d5e0019097ce |
| Online Access: | https://riunet.upv.es/handle/10251/233972 |
| Access Level: | Open access |
| Keyword: | Feasibility study Resins Bioremoval Safety technologies Cultural heritage FTIR. 06.- Garantizar la disponibilidad y la gestión sostenible del agua y el saneamiento para todos 11.- Conseguir que las ciudades y los asentamientos humanos sean inclusivos, seguros, resilientes y sostenibles |
| Summary: | [EN] Aged varnish layers distort the original appearance or integrity of easel paintings and they must be removed in most cases. Toxic solvents (harmful to conservators, the artwork and the environment) are frequently used. To seek an alternative to these harmful products, here we assay the use of safe bacteria as biocleaning agents. Three bacteria (further here identified as Microbacterium oxydans, Acinetobacter johnsonii and Micrococcus luteus) were isolated from the 18th -century easel painting ¿The Glorification of Saint Teresa of Jesus by Christ and the Virgin, accompanied by founding saints,¿ School of José Vergara (1726-1799) with damaged Dammar varnish. In the laboratory, the three isolates and a bacterium widely used in biocleaning (Pseudomonas stutzeri) were grown in oligotrophic broth media supplemented with powdered Dammar resin to assess their tolerance and ability to grow using the Dammar resin components as an energy source. Then, the four bacteria were applied with 2% agar-agar to Dammar varnish mook-ups for 1, 2, 3 and 4 hours to test their degradative capacity. The biological treatment efficiency was analyzed by visual examination, grazing light photography, colorimetric and infrared (FTIR) spectroscopy measurements. According to noticeable changes in FTIR spectra, indicating an alteration of the varnish structure, coupled with the presence of bacteria on the surface, P. stutzeri, A. johnsonii and M. luteus are promising for bioremoval of dammar varnish. In addition, naked-eye change assessment showed more intense changes by Acinetobacter johnsonii. |
|---|