The French National Research Institute for Agriculture, Food, and the Environment (INRAE) is a public research establishment. It is a community of 12,000 people with more than 200 research units and 42 experimental units located throughout France. The institute is among the world leaders in agricultural and food sciences, in plant and animal sciences, and is 11th in the world in ecology and environment. INRAE’s main goal is to be a key player in the transitions necessary to address major global challenges. In the face of the increase in population, climate change, scarcity of resources and decline in biodiversity, the institute develops solutions for multiperformance agriculture, high quality food and sustainable management of resources and ecosystems.
Work environment, missions and activities
You will be member of the Membrane Processing team, which is a part of the research unit Science and Technology of Milk and Eggs (UMR STLO) of the National Research Institute for Agriculture, Food and Environment (INRAE) and National Institute of Higher Education for Agriculture, Food and the Environment (Institut Agro).
Web sites of the research unit and team:
General description of the PhD thesis: “Modelling of serum proteins transmission during micro- and diafiltration of skimmed milk”
Micro- and diafiltration of skimmed milk are industrially applied to separate serum proteins (macromolecules) from casein micelles (nanoparticles), which have different functional properties and use. Despite of a great importance of skimmed milk microfiltration processes, their implementation is based on empirical relations between filtrate flux, serum proteins transmission and operating parameters (pressure and crossflow rate, casein micelle concentration, membrane module configuration). The modelling of filtration-separation of milk proteins can allow a better process optimization. Though filtration kinetics (filtrate flux) was largely studied, less attention was paid to serum proteins transmission, which is limited by proteins convection-diffusion across the gel layer of casein micelles. Therefore, the objective of this thesis is to study (via modelling and experiment) serum proteins transmission during the skimmed milk cross-flow microfiltration processes.
The main questions posed in this work are
(1) how to describe the serum proteins transport across the gel of casein micelles?
(2) how is this transport affected by gel properties?
(3) how are the gel properties affected by the presence of serum proteins?
(4) how is this transport affected by dispersion medium composition and temperature?
We will assume that properties of the gel layer, which are required for the modelling, can be studied via in-situ (Small Angle X-Ray scattering, SAXS, assisted cross-flow filtration) and ex-situ (osmotic compression, rheology, dead-end filtration) experiments.
It is foreseen
(1) to study properties of mixed dispersions of casein micelles and serum proteins via SAXS, osmotic compression, rheology;
(2) to model and to study the serum proteins transmission across the casein micelles gel in controlled conditions of dead-end and cross-flow microfiltration;
(3) to study the influence of ionic composition and temperature of mixed dispersions of casein micelles and serum proteins on the serum proteins transmission during the cross-flow filtration.
Methodological and technical approaches considered
(1) Dead end and cross flow filtration of mixed proteins dispersion.
(2) Osmotic compression of mixed dispersions
(3) Rheological and SAXS analysis of gel layers and osmotically compressed dispersions.
Example of our recent work on the subject:
M. Loginov, F. Doudiès, N. Hengl, M. Karrouch, N. Leconte, F. Garnier-Lambrouin, J. Perez, F. Pignon, G. Gésan-Guiziou (2021). On the reversibility of membrane fouling by deposit obtained during cross-flow ultrafiltration of casein micelle suspension. J. Membrane Sci. 630 (2021) 119289
Training and skills
Recommended training: Master degree (or equivalent) in process engineering;
- Knowledge desired: process engineering, physical chemistry, physics or another relevant field, which allows him/her to work on modelling and experimental analysis of cross-flow filtration (which is an interdisciplinary problem of physical chemistry of colloids and membrane separation);
- Appreciated experience: a first experience in modelling
- Skills sought: autonomy, teamwork, ability to read and communicate in English
INRAE's life quality
By joining our teams, you benefit from (depending on the type of contract and its duration):
- up to 30 days of annual leave + 15 days "Reduction of Working Time" (for a full time);
- parenting support: CESU childcare, leisure services;
- skills development systems: training, career advise;
- social support: advice and listening, social assistance and loans;
- holiday and leisure services: holiday vouchers, accommodation at preferential rates;
- sports and cultural activities;
- collective catering.