In the framework of the research project “Innovative systems and services for transport and production” I-SITE CAP 20-25 (Challenge 2) and the LabEx IMobS3, a 3-year PhD grant is proposed for highly motivated candidates interested in completing a PhD thesis in biological process engineering, biochemical engineering, applied microbiology and biochemical analysis.
Context
The present fossil fuel-based production of energy has led to large-scale industrial expansion. However, the dependence on fossil fuels leads to the gradual depletion of natural resources and to an increase in greenhouse gas emissions with negative effects on global climate.
It is thus essential to develop innovative processes to produce renewable energy sources (2020 Market state and trends report). Biohydrogen is a promising alternative clean energy carrier with a high energy content (142 MJ/kg), twice that of natural gas. Upon combustion of H2, water is the only major by-product. In the coming years, the use of H2 will be generalized with the development of fuel cell in many domains, mainly in automotive industry but also in aerospace, multimedia, and civil engineering (Singla et al., 2021). In recent decades, several biological routes to produce H2 were investigated due to the attractive and renewable characteristics of this energy carrier. Dark fermentation (DF) with mixed cultures represents an interesting way for hydrogen production and allows the valorization of many types of waste. The main advantage of performing DF with mixed culture is the ability of anaerobic bacteria to degrade many complex substrates such as agricultural residues, lignocellulosic biomass, municipal wastes, industrial and domestic effluents (Noblecourt et al., 2018). Moreover, the volatiles fatty acids (VFAs) co-produced during the culture correspond to high added-value building blocks that have many industrial applications (Béligon et al., 2016).
Scientific project and objectives
A two-step process producing biologically two gases, H2 and CH4, will be developed for organic waste valorization. The first step consists in a dark fermentation reactor (hydrolysis/acidogenesis) which allows a partial degradation of organic matter into H2 and metabolites (VFAs, ethanol and lactic acid). Then the liquid outlet of the first reactor can be used in a second reactor for methane production completing organic matter degradation. The gas outlet (H2) can be directly valorized or injected in the second reactor to stimulate hydrogenotrophic Archaea, increasing significantly the methane content. This concept may improve the kinetics of biogas production and increase the profitability of biogas plants.
However, only a high efficiency of the dark fermentation step allows making this two-step process economically viable compared to a simple anaerobic digestion reactor. The aim of this program is, thus, to improve the knowledge of the dark fermentation process for optimizing hydrogen and metabolites production. Then the coupling of the two unitary operations will be studied. A sizing and modeling approach will be considered at this stage.
A continuous process for hydrogen production will be developed using a anaerobic consortium. Artificial media with industrial depackaging food waste will be used as substrates. Experiments will be carried out to better understand the main limiting factors of hydrogen production along with the operational conditions that could improve hydrogen yield. A reactor configuration using an external immersed membrane will be used. This concept was previously designed at Pascal Institute and demonstrated that continuous VFA extraction induced a significant increase in the performance of the system. The Biochemical Methane Potential of the liquid outlet stream will also be determined and compared to methane production using the classical anaerobic digestion process. An optimized configuration will be set up to achieve performances allowing to consider process industrialization.
Requirements
The candidate will have a background in biological process engineering, biochemical engineering, applied microbiology and biochemical analysis. An aptitude for experimentation and teamwork is required.
References
2020 Market state and trends report Gas for Climate 2050. Available at: https://gasforclimate2050.eu/sdm_downloads/market-state-and-trends-report-2020/ [Accessed May 6, 2021].
Béligon, V., Noblecourt, A., Christophe, G., Lebert, A., Larroche, C., and Fontanille, P. (2016). Proof of concept for biorefinery approach aiming at two bioenergy production compartments, hydrogen and biodiesel, coupled by an external membrane. Biofuels 0, 1–12. doi:10.1080/17597269.2016.1259142.
Noblecourt, A., Christophe, G., Larroche, C., and Fontanille, P. (2018). Hydrogen production by dark fermentation from pre-fermented depackaging food wastes. Bioresource Technology 247, 864–870. doi:10.1016/j.biortech.2017.09.199.
Singla, M. K., Nijhawan, P., and Oberoi, A. S. (2021). Hydrogen fuel and fuel cell technology for cleaner future: a review. Environ Sci
Information and contacts
The PhD will be carried out at the GePEB of Institute Pascal in Clermont-Ferrand (http://www.institutpascal.uca.fr). The GePEB conducts research focused on the concept of the biomass conversion with a view to recovering liquid and solid waste into bioenergy, biomolecules and bioproducts.
The start of the thesis is planned for September 2021.
Application deadline June 30th 2021.
Contacts:
Jean-Sébastien GUEZ, Research Engineer,
Pascal Institute Axe GePEB UMR CNRS/SIGMA/UCA 6602, Clermont Auvergne University
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Pierre FONTANILLE, Assistant Professor, Biochemical engineering,
Pascal Institute Axe GePEB UMR CNRS/SIGMA/UCA 6602, Clermont Auvergne University
Director BIO-VALO Platform
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