Erosion bacteria are the main degraders of archaeological wood excavated from waterlogged environments. Light microscopy and analytical pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS) were exploited to study waterlogged archaeological wood ( Pinus sylvestris L.) at different stages of bacterial decay. The research explored the biochemical changes related to erosion bacteria degradation of the secondary cell wall in the wood cells and the chemical changes related to abiotic processes induced by the long-term waterlogged burial environment. Erosion bacteria were demonstrated by chemical analysis to cause significant holocellulose depletion. Detailed analysis of the holocellulose and lignin pyrolysis products revealed only minor chemical changes in the residual structure even after heavy erosion bacteria decay. Chemical changes in the lignin polymer is associated to enzymatic unlocking of the lignocellulose to gain access to the holocellulose fraction of the cell wall. Chemical changes in the holocellulose fraction are suggested to stem from depolymerisation and from alterations in the polymer matrix of the residual wood cell wall structure. Interestingly, a difference was observed between the sound reference wood and the waterlogged archaeological wood without erosion bacteria decay, indicating that long-term exposure in waterlogged environments results in partial decay of the holocellulose even in absence of bacterial activity.

中文翻译：

---

光学显微镜和 Py-GC/MS 分析浸水考古木材中细菌腐烂与化学变化的相关性

侵蚀细菌是从浸水环境中挖掘出的考古木材的主要降解物。利用光学显微镜和分析热解结合气相色谱/质谱 (Py-GC/MS) 来研究在细菌腐烂不同阶段的浸水考古木材 (Pinus sylvestris L.)。研究探索了与侵蚀细菌降解木细胞次生细胞壁相关的生化变化，以及长期浸水掩埋环境引起的与非生物过程相关的化学变化。通过化学分析证明侵蚀细菌会导致显着的全纤维素消耗。对全纤维素和木质素热解产物的详细分析表明，即使在严重侵蚀细菌腐烂之后，残留结构中也只有很小的化学变化。木质素聚合物中的化学变化与木质纤维素的酶促解锁有关，以获得细胞壁的全纤维素部分。建议全纤维素部分的化学变化源于解聚和残留木细胞壁结构的聚合物基质的改变。有趣的是，在健全的参考木材和没有侵蚀细菌腐烂的浸水考古木材之间观察到了差异，表明即使在没有细菌活动的情况下，长期暴露在浸水环境中也会导致全纤维素部分腐烂。建议全纤维素部分的化学变化源于解聚和残留木细胞壁结构的聚合物基质的改变。有趣的是，在健全的参考木材和没有侵蚀细菌腐烂的浸水考古木材之间观察到了差异，表明即使在没有细菌活动的情况下，长期暴露在浸水环境中也会导致全纤维素部分腐烂。建议全纤维素部分的化学变化源于解聚和残留木细胞壁结构的聚合物基质的改变。有趣的是，在健全的参考木材和没有侵蚀细菌腐烂的浸水考古木材之间观察到了差异，表明即使在没有细菌活动的情况下，长期暴露在浸水环境中也会导致全纤维素部分腐烂。