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MICMAC

Microbes for Archaelogical wood Conservation

This project focuses on innovative biological methods of extraction for the preservation of waterlogged wood.

Wood artefacts encounter serious problems when excavated. In fact, sulfur and iron species formed during burial are unstable once exposed to oxygen, leading to salt precipitation and acidification. These alterations are unfortunately often observed after objects are consolidated and dried. In response, chemical extraction or neutralization processes are applied but their efficiency is limited to the wood surface.

The project propose here to exploit the unique properties of some bacteria for anticipating the extraction of iron and sulfur compounds when wood is still wet. This would be the first time biotechnology is addressing the issue of salt precipitation and acidification on waterlogged wood. To this purpose, two different strategies will be adopted: 1) oxidation of sulfur species and 2) complexation of iron species. Exploring biomineralizing capacities of bacteria presents an outstanding interest for developing advanced conservation technologies with no side-effect on health and environment compared to the traditional methods. A preliminary study realized at the University of Neuchâtel have shown promising results :

Photo 

Evaluation of oxidation states of the species present in waterlogged wood impregnated in a solution containing Fe2+ and S2- (pink: sulfate, blue: sulfur). Top: control sample, bottom: sample after bacterial treatment

 

The microbial mechanisms involved will first be deeply investigated over sulfur- and iron-rich phases. Then, a synergetic microbial co-culture will be specially designed and applied in accordance to conservation ethics. Hence, an innovative conservation methodology will be developed and finally assessed on model wood samples artificially degraded. Particular attention will be devoted to the efficiency and the impact on wood structure of the proposed treatment.

Based on the results achieved, I will thus propose a breakthrough innovation and eco-friendly strategy for the conservation of wooden artefacts after excavation. A real progress is expected in terms of stability, effectiveness, and decreased toxicity. Hence, this project represents a pioneer and inventive research for the conservation-restoration of waterlogged wood.

This is a pioneer and innovative project in the field of waterlogged wood conservation and preservation.

Other institutes involved in the project :

  • Laboratory LAMUN
  • Haute Ecole Arc Conservation-Restauration , University of applied sciences Western Switzerland
  • HEIA-FR (Haute Ecole d’Ingénieurie et d’Architecture de Fribourg), Fribourg, Switzerland
  • Laboratoire Arc’Antique, Nantes, France
  • Archaeological park and museum Laténium
  • Archaeological service of the canton Bern

Contacts

Edith Joseph, professeure assistante

 

Magdalena Albelda-Berenguer, doctorante

 

Mathilde Monachon, doctorante

 

Lidia Mathys-Panaguzzi, laborantine