Biological oxidation of iron sulfides

Monachon, Mathilde (University of Neuchâtel, Switzerland) ; Albela-Berenguer, Magdalena (University of Neuchâtel, Switzerland) ; Joseph, Edith (Haute Ecole Arc Conservation-Restauration, HES-SO University of Applied Sciences and arts Western Switzerland)

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.


Keywords:
Article Type:
scientifique
Faculty:
Design et Arts visuels
Branch:
Conservation
School:
HE-Arc CR
Institute:
Unité de recherche en Conservation-restauration de la Haute Ecole Arc - UR-ARC CR
Subject(s):
Conservation - Restauration
Date:
2019-02
Pagination:
28 p.
Published in:
Advances in Applied Microbiology
Numeration (vol. no.):
2019, vol. 107, pp. 1-27
DOI:
ISSN:
0065-2164
Appears in Collection:

Note: The status of this file is: restricted


 Record created 2020-03-25, last modified 2020-10-27

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