Working environment, missions and activities

Scientific background of the project:

The European Union and France have set themselves the ambitious goal of achieving a zero-carbon economy by 2050. The bio-economy should play an important role in replacing petrochemicals with bio-sourced products from renewable biological resources. In this context, the use of organic waste as a resource (i.e. environmental biorefinery) represents an attractive option because of the high potential for replacing fossil fuels and the low (often negative) cost of raw materials. However, organic waste is a complex, heterogeneous and time-variable matrix, and these characteristics severely limit its potential for recovery. Among the various technological options currently being developed for the production of higher added-value organic products for green chemistry applications, microbial electrochemical technologies are promising emerging technologies. These systems rely on the ability of certain microorganisms to catalyze oxidation or reduction reactions at the electrode surface, thereby eliminating organic molecules, producing hydrogen or electricity, and providing new options for controlling microbial communities.

In this thesis project we propose to develop an innovative electro-fermentation process for the production of platform molecules from waste. Specifically, the work will focus on optimizing a chain elongation process for the production of medium-chain fatty acids such as caproic acid (C6) or caprylic acid (C8) from shorter molecules such as acetic acid (C2) or butyric acid (C4), which are major products of waste fermentation.

Mission and Activities:

The work will combine both experimental approaches with the realization of microbial fermentations in reactors and more theoretical approaches to analyze microbial communities, metabolic pathways and associated physicochemical constraints. The objectives of the thesis are:
1) To screen different microbial ecosystems and test their ability to perform chain elongation from different substrates or substrate mixtures.
2) To evaluate the impact of electro-fermentation on chain elongation of selected ecosystems and optimize their performance.
3) To analyze microbial communities and chain elongation mechanisms under electro-fermentation conditions.

Project Partners:

This thesis is part of the ElectroMIC project funded under the national acceleration strategy PEPR "Biomass, Biotechnology and Sustainable Technologies for Chemistry and Fuels" (B-BEST). The PhD student will work in collaboration with the various project partners. In particular, the choices of microbial ecosystems and substrates studied will be discussed with the different members of the consortium.

Host laboratory:

The Laboratory of Environmental Biotechnology (LBE) is an INRAE unit located in Narbonne and attached to the Occitanie-Montpellier INRAE center. The research carried out at LBE is aimed at developing the concept of environmental biorefinery, which consists of upgrading residues, wastes, organic effluents and certain biomasses into products of industrial interest (bioenergy, biomolecules and organic fertilizers) while minimizing their environmental and health impact.

Required training and skills

Master/Engineer

Le profil que nous recherchons :

•    Recommended training: 5 years' higher education (Master's degree or equivalent) in process engineering or microbiology.
•    A good level of English is required.
•    Skills required: autonomy, teamwork, rigour, good interpersonal skills, ability to write, supervision of students.

Desirable experience: running bioreactors, analyzing mixed microbial communities, scientific publications.

Contacts

Nicolas Bernet (nicolas.bernet@inrae.fr), Eric Trably (eric.trably@inrae.fr), Elie Le Quéméner (elie.le-quemener@inrae.fr)