Microbially induced calcium carbonate precipitation in fossil consolidation treatments : Preliminary results inducing exogenous Myxococcus xanthus bacteria in a miocene Cheirogaster richardi specimen
Marín-Ortega, Silvia (Universitat de Barcelona. Heritage Conservation-Restoration Research Group)
Calvo Torras, Ma. de los Ángeles (Universitat Autònoma de Barcelona. Departament de Sanitat i d'Anatomia Animals)
Iglesias Campos, Manuel Ángel (Universitat de Barcelona. Heritage Conservation-Restoration Research Group)

Fecha:	2023
Resumen:	This research paper proposes Microbially Induced Calcium Carbonate Precipitation (MICP) as an innovative approach for palaeontological heritage conservation, specifically on deteriorated carbonate fossils. Due to its efficiency in bioconsolidation of carbonate ornamental rocks, Myxococcus xanthus inoculation on carbonate fossils was studied in this research. Treatment was tested on nine fossil samples from decontextualized fragments of Cheirogaster richardi specimens (Can Mata site, Hostalets de Pierola, Catalonia, Spain). The main objective was to evaluate whether treatment with Myxococcus xanthus improved fossil surface cohesion and hardness and mechanical strength without significant physicochemical and aesthetic changes to the surface. Chemical compatibility of the treatment, penetration capacity and absence of noticeable changes in substrate porosity were considered as important issues to be evaluated. Samples were analysed, before and after treatment, by scanning electron microscopy, weight control, spectrophotometry, X-ray diffraction analysis, water absorption analysis, pH and conductivity control, Vickers microindentation and tape test. Results show that hardness increases by a factor of almost two. Cohesion also increases and surface disaggregated particles are bonded together by a calcium carbonate micrometric layer with no noticeable changes in surface roughness. Colour and gloss variations are negligible, and pH, conductivity and weight hardly change. Slight changes in porosity were observed but without total pore clogging. To sum up, results indicate that Myxococcus xanthus biomineralisation is an effective consolidation treatment for carbonate fossils and highly compatible with carbonate substrates. Furthermore, bacterial precipitation of calcium carbonate is a safe and eco-friendly consolidation treatment.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Microbially induced calcium carbonate precipitation ; Conservation ; Fossil ; Myxococcus xanthus ; Paleontological heritage ; Bioconsolidation
Publicado en:	Heliyon, Vol. 9 (june 2023) , ISSN 2405-8440

DOI: 10.1016/j.heliyon.2023.e17597
PMID: 37449105

17 p, 11.9 MB

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