Development and evaluation of a biotechnological protocol for the conservation of archaeological waterlogged wood

Archaeological waterlogged wood faces serious problems when is exposed to the air. During burial, sulfur and iron species are formed and accumulated in the wood artefacts. After excavation, the exposure of these compounds to oxygen results in salt precipitation and acidification. These alterations are a major concern for conservators, as they have been observed even after consolidation and drying of the artefacts. In order to remediate the visible damage, chemical extraction and neutralization protocols have been applied with more or less success.

This PhD is involved within the MICMAC project: MICrobes for the Archaeological wood Conservation (PI: Edith Joseph). The aim of this project is to develop and evaluate a preventive method for the extraction and stabilization of sulfur and iron compounds when the wood is still wet, using microorganisms.

Biological methods for the conservation of archaeological wood have been poorly reported. However, the efficacy of microbiological processes applied to the preservation of other cultural heritage artefacts have been proved by the PI. In this thesis, a biotechnological extraction treatment will be developed, following two different strategies: 1) the oxidation of iron and sulfur species by selected bacteria and, 2) the removal of ferric iron species using microbial siderophores.