Hydrogen consumption kinetics by subsurface microbial communities: what impact on natural hydrogen flows to the surface?

It has been established that molecular hydrogen (H₂) is present on the planet in the form of diffuse or continuous emanations. Nevertheless, many questions remain regarding its potential for exploitation. Hydrogen is an important electron donor (reductant) for subsurface ecosystems. Recent studies using metagenomics, marker gene sequencing and microbial cultures have revealed a wide range of hydrogen-trophic microorganisms whose metabolic activity can consume a large proportion of the hydrogen produced at depth. However, there are still insufficient data regarding the composition of microbial populations at natural hydrogen sites and their H2 consumption kinetics to predict their actual impact on the flow of hydrogen to the surface.
The aim of this thesis is to study the microbial populations and their metabolic activities at a known natural hydrogen site in the United States using a metagenomic approach coupled with on-site geochemical measurements. H2 consumption kinetics experiments will then be carried out in the laboratory using a consortium collected during sampling campaigns in order to characterize the microbial response at the compositional and functional levels to different conditions (pH, temperature, salinity, various H2 fluxes, etc.) and to estimate consumption rates. These analyses will enable us to ascertain the metabolic potential of the communities and evaluate the impact of geochemical conditions on their capacity to metabolize hydrogen. The successful candidate will have a University Master degree with a specialization in microbiology, biotechnology and/or bioinformatics.

Keywords: Microbiology, Metagenomics, Natural hydrogen, Biogeochemistry, Decarbonised energy

• Academic supervisor    Dr. Senta BLANQUET, IFPEN, ORCID : 0000-0001-8533-3274
• Doctoral School    ED435 ABIES, Université Paris Saclay
• IFPEN supervisor    Dr. Elodie MULLER, elodie.muller@ifpen.fr, ORCID : 0000-0002-2430-9438
• PhD location    IFPEN, Rueil-Malmaison, France
• Duration and start date    3 years, starting in the fourth quarter 2025 (Novembre 3)
• Employer    IFPEN
• Academic requirements    University Master degree in microbiology, molecular biology or biotechnology.
• Language requirements    English level B2 (CEFR), some knowledge of French or willingness to learn French
• Other requirements    The student must have an open mind for geochemical analyses and environmental microbiology.

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.