Université de Neuchâtel

Isolation and characterization of oxalotrophic bacteria from tropical soils

Bravo, Daniel ; Braissant, Olivier ; Cailleau, Guillaume ; Verrecchia, Eric ; Junier, Pilar

In: Archives of Microbiology, 2015, vol. 197, no. 1, p. 65-77

The oxalate–carbonate pathway (OCP) is a biogeochemical set of reactions that involves the conversion of atmospheric CO2 fixed by plants into biomass and, after the biological recycling of calcium oxalate by fungi and bacteria, into calcium carbonate in terrestrial environments. Oxalotrophic bacteria are a key element of this process because of their ability to oxidize calcium...

Université de Neuchâtel

Fungi, bacteria and soil pH : the oxalate–carbonate pathway as a model for metabolic interaction

Martin, Gaëtan ; Guggiari, Matteo ; Bravo, Daniel ; Zopfi, Jakob ; Cailleau, Guillaume ; Aragno, Michel ; Job, Daniel ; Verrecchia, Eric ; Junier, Pilar

In: Environmental Microbiology, 2012, vol. 14, no. 11, p. 2960-2970

The oxalate–carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO2. In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria,...

Université de Neuchâtel

Experimental calcium-oxalate crystal production and dissolution by selected wood-rot fungi

Guggiari, Matteo ; Bloque, Raphael ; Aragno, Michel ; Verrecchia, Eric ; Job, Daniel ; Junier, Pilar

In: International Biodeterioration & Biodegradation, 2011, vol. 65, no. 6, p. 803-809

Twenty-six species of white-rotting Agaricomycotina fungi (Basidiomycota) were screened for their ability to produce calcium-oxalate (CaOx) crystals in vitro. Most were able to produce CaOx crystals in malt agar medium in the absence of additional calcium. In the same medium enriched with Ca2+, all the species produced CaOx crystals (weddellite or whewellite). Hyphae of...

Université de Neuchâtel

Use of an isothermal microcalorimetry assay to characterize microbial oxalotrophic activity

Bravo, Daniel ; Braissant, Olivier ; Solokhina, Anna ; Clerc, Martin ; Daniels, Alma U. ; Verrecchia, Eric ; Junier, Pilar

In: FEMS Microbiology Ecology, 2011, vol. 78, no. 2, p. 266–274

Isothermal microcalorimetry (IMC) has been used in the past to monitor metabolic activities in living systems. A few studies have used it on ecological research. In this study, IMC was used to monitor oxalotrophic activity, a widespread bacterial metabolism found in the environment, and particularly in soils. Six model strains were inoculated in solid angle media with K-oxalate as the sole carbon...

Université de Neuchâtel

Use of the frc gene as a molecular marker to characterize oxalate-oxidizing bacterial abundance and diversity structure in soil

Khammar, Nadia ; Martin, Gaëtan ; Ferro, Katia ; Job, Daniel ; Aragno, Michel ; Verrecchia, Eric

In: Journal of Microbiological Methods, 2009, vol. 76, no. 2, p. 120-127

Oxalate catabolism, which can have both medical and environmental implications, is performed by phylogenetically diverse bacteria. The formyl-CoA-transferase gene was chosen as a molecular marker of the oxalotrophic function. Degenerated primers were deduced from an alignment of frc gene sequences available in databases. The specificity of primers was tested on a variety of...