Observations on microbial growth during conservation treatment of waterlogged archaeological wood

During conservation treatment of simulated archaeological wood, multicoloured microbial colonization and slime layers developed at the liquid/air interface after seven months of impregnation in PEG (polyethylene glycol). This microbial growth, leaving behind a foul odour, is a major problem for wood conservation worldwide. Despite presence of microbes, observations using light microscopy revealed no wood-degrading activities within the wood tissue of test samples. Biofilm surrounding wooden objects may have a negative effect on PEG penetration rate, whereas discoloration by blue stain fungi has a more aesthetic drawback. From the conservator's point of view, microbial growth during conservation treatment could constitute a health problem rather than a threat to the actual wooden artifacts.