ISTerre seminar

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Mechanisms of bacterial biofilm formation and its impact on the surrounding environment: cases on altering pH, Hg speciation, and Fe oxidation state

Wednesday 13 November 2024 - 10h00

séminaire post-doc: Elena Yunda  - Equipe Géochimie
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Biofilms are natural habitats of microorganisms that grow as a community and play roles in various types of environmental processes involving the transformation of organic and inorganic compounds. This talk will describe how the formation of biofilms and bacterial molecular composition are influenced by the chemical properties of the surrounding media and how bacterial cells, in turn, change their close environment through their metabolic action. An approach to monitoring these processes in situ consists in the application of Fourier transform infrared spectroscopy in the attenuated-total-reflection mode, allowing a study of changes in the relative concentration of main biomolecules in hydrated biofilm samples. Biofilms of lactic acid bacteria formed on functionalized (-OH, -CH3, or -NH3+) surfaces and biofilms of iron-reducing bacteria cultivated on poorly-crystalline iron hydroxides are described, and the effect of growth conditions of the latter species on the rate of mercury methylation is presented. Finally, the last part of the talk will link a presented approach of studying model bacterial species in biofilms to the context of a new postdoctoral project (2024-2026) aiming to improve the mechanistic understanding of microbial contribution to alteration of silicate minerals.

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Organizing team : Organisation labo

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères