PhD position OT-30393
Understanding redox homeostasis in gasfed purple non-sulfur bacteria for enhanced performance
11100 NARBONNE
INRAE presentation
The French National Research Institute for Agriculture, Food, and Environment (INRAE) is a major player in research and innovation. It is a community of 12,000 people with 272 research, experimental research, and support units located in 18 regional centres throughout France. Internationally, INRAE is among the top research organisations in the agricultural and food sciences, plant and animal sciences, as well as in ecology and environmental science. It is the world’s leading research organisation specialising in agriculture, food and the environment. INRAE’s goal is to be a key player in the transitions necessary to address major global challenges. Faced with a growing world population, climate change, resource scarcity, and declining biodiversity, the Institute has a major role to play in building solutions and supporting the necessary acceleration of agricultural, food and environmental transitions.
Work environment, missions and activities
About INRAE-LBE
The Laboratory of Environmental Biotechnology (LBE) at INRAE is a world-leading research institute dedicated to innovative environmental technologies. We focus on developing sustainable solutions to address pressing global environmental challenges. Our interdisciplinary team of scientists and engineers works collaboratively to advance the field of environmental biotechnology, with a particular emphasis on resource recovery, wastewater treatment, and bioenergy production.
Job description and scientific context
Securing sustainable food production is imperative, and microbial protein (MP) offers a promising alternative to plant- or animal-derived proteins. The PURPROTEX project, funded by the French ANR, aims to develop and optimize a purple non-sulfur bacteria (PNSB)-based MP production process for the valorization of gaseous streams (H2, CO2, N2, and gaseous organic acids).
PNSB possess unique metabolic flexibility, including anoxygenic photosynthesis, photoheterotrophy, CO2 fixation, and biological nitrogen fixation. While PNSB have been studied as model organisms for bacterial photosynthesis, most research has focused on their photoheterotrophic capabilities and their autotrophic and diazotrophic metabolisms remain poorly understood, particularly regarding how electron allocation and energy distribution affect redox homeostasis, growth rates, and biomass composition.
As part of PhD 1 in PURPROTEX, you will experimentally characterize the metabolic pathways governing redox homeostasis in various specialized PNSB strains, focusing on diazotrophic and autotrophic growth.
You will also evaluate process performance in both batch tests (for screening of operational conditions) and continuous gas-fed photobioreactors.
Key objectives
- Strain benchmarking: Screen and rank specialized PNSB strains for growth rates and biomass yields under autotrophic and diazotrophic conditions under varying light, pH, temperature, and gas compositions.
- Metabolic pathway identification: use of advanced molecular tools to identify essential gene sets governing autotrophy, BNF, CO2 fixation, and redox regulation.
- Continuous estimation of performance indicators: operate state-of-the-art continuous gas-fed photobioreactors to generate dynamic and steady-state KPI datasets.
Specific tasks
- Execute batch strain screening experiments to assess performance across various gas ratios, wavelengths, and light intensities.
- Perform DNA/RNA extraction, mutant library generation, and analysis of sequencing data.
- Set up, operate, and monitor 5-30 L continuous gas-fed photobioreactors under different operational strategies.
- Collect operational data and biomass samples, transferring datasets to project partners for biomass characterization and hybrid model development.
Training and skills
- Academic background: Master’s degree (or equivalent) in Microbiology, Bioprocess Engineering, Biotechnology, or a related discipline.
- Skills: Hands-on experience with microbial cultivation, bioreactor operation, or molecular biology techniques (e.g., DNA/RNA extraction, sequencing workflows).
- Attributes: self-motivated, rigorous, enthusiastic about experimental problem-solving, and comfortable working both independently and as part of an interdisciplinary team.
- Language: fluent use of English; knowledge of French is an advantage but not required.
- Motivation: the candidate should be enthusiastic and outgoing when searching for solutions to challenges that will arise during the experimental work. The candidate should aim for scientific output in top conferences and scientific journals.
INRAE's life quality
- Cutting-edge research environment: work in a state-of-the-art laboratory equipped with the latest technologies in environmental biotechnology, gas-fed photobioreactor platforms, ATEXcertified gas handling systems, and molecular biology facilities. The equipment is fully shared, so you will have access to all the facilities.
- Mentorship and training: receive guidance from leading experts in the field and access to a comprehensive training program.
- Collaborative network: engage with a dynamic interdisciplinary team spanning microbiology,bioinformatics, bioprocess engineering, and food science across INRAE and international partners.
- Funding and resources: full doctoral contract funding, research support, and dedicated travel budget for international conferences and stays.
- Career development: opportunities for professional growth, including workshops, seminars, and networking events.
- Work atmosphere: Join a supportive, friendly, and dynamic team passionate about driving
innovative solutions for environmental sustainability. - Great working conditions: 30 days of annual leave (+ 15 days of time recovery); support for parenting; inexpensive collective catering; flexible schedule; on-site sports facilities; Sunny Mediterranean weather.
Specifically, the PhD student will learn advanced bioprocess engineering, gas-fed photobioreactor operation, omics data analysis, functional genomics, and data-driven bioprocess evaluation. The student will have the continuous support of experienced researchers and engineering technicians.
How to apply
Interested candidates should submit the following documents to gabriel.capson-tojo@inrae.fr and laura.alvarez-fraga@inrae.fr by September 15th, 2026:
- A detailed CV, including academic achievements and relevant research experience.
- A cover letter outlining your motivation and suitability for the PhD project.
We look forward to receiving your application and welcoming you to our team at INRAE-LBE!
All persons employed by or hosted at INRAE, a public research establishment, are subject to the Civil Service Code, particularly with regard to the obligation of neutrality and respect for the principle of secularism. In carrying out their functions, whether or not they are in contact with the public, they must not express their religious, philosophical or political convictions through their behaviour or by what they wear. > Find out more: fonction publique.gouv.fr website (in French)