Advances in Understanding Microbial Deterioration of Buried and Waterlogged Archaeological Woods: A Review

Abstract

This review provides information on the advances made leading to an understanding of the micromorphological patterns produced during microbial degradation of lignified cell walls of buried and waterlogged archaeological woods. This knowledge not only serves as an important diagnostic signature for identifying the type(s) of microbial attacks present in such woods but also aids in the development of targeted methods for more effective preservation/restoration of wooden objects of historical and cultural importance. In this review, an outline of the chemical and ultrastructural characteristics of wood cell walls is first presented, which serves as a base for understanding the relationship of these characteristics to microbial degradation of lignocellulosic cell walls. The micromorphological patterns of the three different types of microbial attacks—soft rot, bacterial tunnelling and bacterial erosion—reported to be present in waterlogged woods are described. Then, the relevance of understanding microbial decay patterns to the preservation of waterlogged archaeological wooden artifacts is discussed, with a final section proposing research areas for future exploration.

Biodeterioration Assessment of a Unique Old Pharaonic Kingdom Wooden Statue Using Advanced Diagnostic Techniques

“…The deterioration levels were defined as weak (from 0 to 33 % of decrease), moderate (from 34 to 66% of decrease), and severe (from 67 to 100% As expected, as shown in Figure 8a, the false-colour FPA images of the Acacia standard sample showed the highest amounts (corresponding to the red colour in the maps and the scale bar) of cellulose and lignin (Figure 8b, orange and green rectangles, respectively) and the lower amount of deterioration products (Figure 8a, blue rectangle). The FPA map of sample #1 for cellulose still showed a good preservation and a wide distribution with only some degraded regions (blue spots), while the lignin content was quite low with only some preserved pale red spots [13].…”

“…Buried archaeological wood is often exposed to the microbiological processes, where different types of microorganisms (mainly bacteria and microfungi) can actively attack wood depending on the soil environment [11,12]. The most destructive white-rot and brown-rot fungi may attack partially dried woods in the presence of oxygen [13][14][15][16]. Therefore, these fungi activities are relevant only for buried archaeological wood in arid regions.…”

New frontiers review of some recent conservation techniques of organic and inorganic archaeological artefacts against microbial deterioration

“…The micro-morphological patterns created during microbial degradation of lignified cell walls of buried and waterlogged archaeological woods is a crucial diagnostic signature for identifying the types of microbial attacks present in woods and help in the development of targeted methods for more effective preservation of wooden objects of historical and cultural importance. Also, the identification of ancient wood species and description of their weathering processes are essential first stages in the scientific preservation of wooden cultural heritage ( Singh et al, 2022 ).…”

Bacterial Degradation of Wood by Tunnel Formation: Role of TEM in Understanding the Intricate Architecture of Tunnels and the Cell Wall Degradation Process

“…Subsequently, the secondary wall layers form, with S1, S2, and S3 deposited sequentially. Although this organization of the cell wall is resolvable in high-magnification images obtained using LM and confocal laser scanning microscopes, TEM provides superior textural information [21–23] (Figure 2).

Figure 1:Transverse section of a pine wood showing lignin autofluorescence.

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