Laboratory of Technologies for Heritage Materials, Institute of Chemistry, University of Neuchâtel, Neuchâtel, Switzerland.
Laboratory of Technologies for Heritage Materials, Institute of Chemistry, University of Neuchâtel, Neuchâtel, Switzerland; Haute Ecole Arc Conservation-Restauration, University of Applied Science, HES-SO, Avenches, Switzerland.
Adv Appl Microbiol. 2019;107:1-27. doi: 10.1016/bs.aambs.2018.12.002. Epub 2019 Feb 14.
The biological oxidation of minerals and ores, called bioleaching, has been studied for the last decades to solubilize metals and recover them. In particular, iron sulfides are the most studied ores for an optimum extraction of different metals, such as copper or zinc. The use of chemolithotrophic bacteria, as Acidothiobacillus ferrooxidans, to oxidize both iron and sulfur species in aerobic conditions and at acidic pH shows promising results. In the field of heritage preservation, the development of "green" treatments is more and more studied. Waterlogged archeological wood presents an accumulation of iron sulfides within its structure, which, after exposition to oxygen, lead to salt precipitation and acidification and so to the degradation of the wooden artifact. A new extraction method, based on the dissolution of iron sulfides by the use of bacteria could be an alternative to the current chemical extraction methods, as being more respectful and ecological. While A. ferrooxidans is very effective in mines and groundwater, in the field of conservation-restoration of wood, Thiobacillus denitrificans is a better candidate as it grows at neutral pH, which is less aggressive for organic substrates (wood here). Preliminary studies show the efficiency of T. denitrificans for the dissolution of iron sulfides, as the concentration of nitrates used as electron donors decreases while the concentration of sulfates produced increases without degrading the wooden matrix. Long-term behavior should be studied to assess the stability of the artifacts after treatment.
矿物和矿石的生物氧化，称为生物浸出，在过去几十年中一直被研究用于溶解金属并回收它们。特别是，硫化铁是研究最多的矿石，用于最佳提取不同的金属，如铜或锌。使用化能自养细菌，如氧化亚铁硫杆菌，在有氧条件下和酸性 pH 值下氧化铁和硫物种，显示出有希望的结果。在遗产保护领域，“绿色”处理方法的开发越来越受到研究。水浸考古木材在其结构内积累了硫化铁，这些硫化铁在暴露于氧气后会导致盐沉淀和酸化，从而导致木质文物的降解。一种新的提取方法，基于使用细菌溶解硫化铁，可以替代当前的化学提取方法，因为它更具尊重性和生态性。虽然氧化亚铁硫杆菌在矿山和地下水中非常有效，但在木材保护修复领域，脱氮硫杆菌是更好的候选者，因为它在中性 pH 值下生长，对有机基质（此处为木材）的腐蚀性较小。初步研究表明，脱氮硫杆菌溶解硫化铁的效率很高，因为用作电子供体的硝酸盐浓度降低，而产生的硫酸盐浓度增加，同时不会降解木质基质。应研究长期行为，以评估处理后文物的稳定性。
