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

Bacterially Induced Mineralization of Calcium Carbonate in Terrestrial Environments: The Role of Exopolysaccharides and Amino Acids

Braissant, Olivier ; Cailleau, Guillaume ; Dupraz, Christophe ; Verrecchia, Eric P.

In: Journal of Sedimentary Research, 2003, vol. 73, no. 3, p. 485-490

This study stresses the role of specific bacterial outer structures (such as glycocalix and parietal polymers) on calcium carbonate crystallization in terrestrial environments. The aim is to compare calcium carbonate crystals obtained in bacterial cultures with those obtained during abiotically mediated synthesis to show implications of exopolysaccharides and amino acids in the mineralogy and...

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

Cycle du carbone et biominéralisation carbonatée en milieu continental : la diagénèse des phases oxalate-carbonate = Carbon cycle and carbonate biomineralization in terrestrial environments

Cailleau, Guillaume ; Verrecchia, Eric (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2005 ; 1840.

In terrestrial environments, the carbon sequestration pool in the global carbon cycle is almost entirely attributed to soil and plant organic carbon storage while soil mineral carbon is generally neglected. Nevertheless, significant biologically induced accumulations of carbonate have been observed in soils under the tropical tree "iroko" (Milicia excelsa). Without an input of calcium from...

Université de Neuchâtel

Biomineralization in plants as a long-term carbon sink

Cailleau, Guillaume ; Braissant, Olivier ; Verrecchia, Eric P.

In: Naturwissenschaften, 2004, vol. 91, p. 191-194

Carbon sequestration in the global carbon cycle is almost always attributed to organic carbon storage alone, while soil mineral carbon is generally neglected. However, due to the longer residence time of mineral carbon in soils (102–106 years), if stored in large quantities it represents a potentially more efficient sink. The aim of this study is to estimate the mineral carbon accumulation due...