Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSE(MINECO-FEDERpu

Cabestrero Aranda, Óscar

Sanz Montero, M. Esther

Sánchez-Román, Mónica

(MINECO-FEDERDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasFALSEpu

Docta Complutense

Geophysical Research AbstractsVol. 20, EGU2018-16859-1, 2018EGU General Assembly 2018© Author(s) 2018. CC Attribution 4.0 license.Mg-rich carbonates mediated by a bacterium isolated from an extremealkaline lake in Central SpainM. Esther Sanz- Montero (1), Óscar Cabestrero (1), and Mónica Sánchez-Román (2)(1) Mineralogy and Petrology Department, University Complutense of Madrid, Spain, (2) Vrije University Amsterdam, EarthSciences Department, Amsterdam, The NetherlandsMicrobial mats known to contain up to 45% of hydromagnesite and other Mg-rich carbonates (nesquehonite,dolomite) are present in Las Eras, a highly alkaline and brackish to saline playa-lake situated about 150 km northof Madrid, Central Spain. This water body contains a high concentration of chloride with dominant carbonateover sulphates ions, which results in pH values ranging from 9.2 to more than 11. Unlike, other soda lakes,Las Eras is characterized by significant amounts of Mg that, in addition to Na-carbonates, favor the formationof Mg-carbonates (Cabestrero and Sanz-Montero, 2016). Here we report the bacterial precipitation of Mg-richcarbonates (hydromagnesite, dypingite and dolomite, among others) mediated by an isolated bacterium from theplaya lake microbial-mat. Scanning electron microscopy (SEM) images shows that the carbonate precipitates areclosely associated to bacterial cells and extra-cellular polysaccharides (EPS). Analysis of the 16S rRNA sequenceof this isolated bacterium revealed a 99.8% identity (i.e. same species) with Desemzia incerta (Y17300).This EPS-forming bacterium was cultivated in a saline and organic rich solid medium at 30º C, in order to simulatethe extreme conditions in this playa lake system and the precipitation in its microbial mat. This bacterium belongsto the Firmicutes order Lactobacillales (Stackebrandt et al. 1999) and has also been isolated in other extremeenvironments as cold desert soils, gold mines biofilms (Yavad et al., 2014; Drewniak et al., 2008).The role that microorganisms have in the biological process and their influence over the mineralogy of the pre-cipitates is still not understood. Thus, certain microbial species have been found to be associated with biomineralprecipitation in many different environments such as saline habitats, biofilms, and soils (e.g., Sánchez-Románet al., 2009a,b; Bontognali et al., 2012). Relationships between microbial species and biomineral characteristicshave been suggested, although the biological precipitation mechanisms as well as the impact of this processin the microbial ecology of the precipitating microorganisms are still unknown. In this work, we expanded thecurrent knowledge on culturable diversity of carbonatogenic bacteria by providing evidence for the precipitationof Mg-rich carbonates by Firmicutes. Moreover, bacterial Mg-rich carbonate precipitation could be of importancein bioremediation of CO2 and Mg in extreme saline and alkaline environments.Acknowledgments: Project CGL2015-66455-R (MINECO-FEDER).References:Bontognali TRR, Vasconcelos C, Warthmann RJ, Lundberg R, McKenzie JA (2012). Terra Nova 24: 248-254.Cabestrero, O, Sanz Montero, ME (2016). Journal of Paleolimnology, 19: 1-19.Drewniak L, Styczek A, Majder-Lopatka M, Sklodowska A (2008). Environ Pollut. 156: 1069-47.Sánchez-Román M, Vasconcelos C, Warthmann RJ, Rivadeneyra MA, McKenzie JA (2009a). In: Perspectives inSedimentary Geology: a Tribute to the Career of Robert Nathan, Vol. 41, pp. 167–178. IAS Special Publication.Sánchez-Román M, McKenzie JA, de Luca Rebello Wagener A, Rivadeneyra MA, Vasconcelos C, (2009b). EarthPlanet. Sci. Lett. 285: 131–139.Stackebrandt E, Schumann P, Swiderski J, Weiss N (1999). Int. J. Syst. Bacteriol. 49: 185-188.Yadav AN, Sachan S.G, Vema P, Tyagi SP, Kaushik R, Saxena A.K. (2014). World J Microbiol Biotechnol. 31:95-108.

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Mg-rich carbonates mediated by a bacterium isolated from an extreme alkaline lake in Central Spain

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Mg-rich carbonates mediated by a bacterium isolated from an extreme alkaline lake in Central Spain

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