M/F PhD Thesis Optimized Biocatalytic Processes for the Synthesis Valuable Hydroxyketones

Job Description

Thesis Subject

This project was awarded funding through the CNRS PRIME 2026 call for proposals under the Mission for Transversal and Interdisciplinary Initiatives (MITI).

The objective is to synthesize hydroxyketones enzymatically. These molecules are used in the health, sweetener, and flavoring sectors. Chemical synthesis methods are challenging due to the number of steps, the formation of byproducts, the use of toxic metal catalysts, and organic solvents. Enzymes, proteins derived from microorganisms, offer an alternative because they accelerate reaction rates, limit byproduct formation, and operate under mild conditions (aqueous solvent, atmospheric pressure, neutral pH). The project aims to utilize transketolase (TK) from microorganisms to generate usable hydroxyketones in a few steps, under mild and environmentally friendly conditions. The challenges concern i) optimizing the reaction in terms of yield and quantity of product obtained, ii) recycling the enzyme(s) and their implementation in continuous flow reactors. Regarding the latter, TK has previously been immobilized on various supports14 by adsorption or covalent bonding, but none of these supports has allowed the development of continuous flow reactors for the synthesis of α-hydroxyketones on the scale of several grams. The interdisciplinary and complementary skills of the two teams involved will make it possible to overcome these obstacles, firstly by using mutagenesis techniques to increase the activities of the enzyme towards the targeted substrates and to show the feasibility of the reaction on an analytical scale (skills of the Clermont-Ferrand Chemistry Institute-ICCF, INC) and secondly by developing the reaction on a larger scale by immobilizing the enzyme and implementing it in continuous flow reactors (skills of the Institut-Pascal-IP, Clermont-Ferrand, INSIS).
For the ICCF part, the doctoral student will be in charge of screening the TK libraries using qualitative tests in semi-solid medium on plates and quantitative tests in liquid medium in 96-well microplates using the ICCF robotic platform. The most efficient mutated TKs, leading to the highest activities, will be produced at the ICCF on a small scale (a few milligrams) for kinetic testing (determination of constants Km, Vmax, kcat) and analytical-scale syntheses. The products obtained will be purified and characterized by MS and NMR. Furthermore, the PhD student will be trained in enzyme modification techniques by the engineer in charge of the ICCF microbiology department and in molecular modeling by the engineer responsible for the ICCF platform. The PhD student will have the opportunity to travel, if desired, to one of the French or European laboratories with which we collaborate to acquire more specific skills.
For the IP component, the candidate will be responsible for the production and purification of TKs in larger quantities (5-10 liter reactors for the production of several grams) using the Plat'ine platform at Polytech Clermont. The doctoral student will establish immobilization protocols using Convective Interaction Media® (CIM) technology and determine immobilization rates and residual activities. The reactions will then be carried out in flow bioreactors. The student will also be able to use statistical tools such as design of experiments (DoE), response surface methods (RSM), and/or principal component analysis (PCA) to optimize experiments and identify key parameters governing both immobilization and enzymatic catalysis processes.

Your Work Environment

The doctoral student will work on two sites: the Clermont-Ferrand Chemistry Institute ICCF (BIOMETA team) belonging to the INC of the CNRS and the Pascal Institute - IP (GEPEB Axis) belonging to the INSIS of the CNRS, both located on the Cézeaux campus of the Clermont Auvergne University (UCA) in Aubière.

• Clermont-Ferrand Institute of Chemistry (ICCF-UMR6296), BIOMETA team: expertise in bioorganic chemistry and biocatalysis: - expression of recombinant enzymes, engineering by mutagenesis: Muriel JOLY (IE UCA) - molecular modeling: Lionel NAUTON (IR CNRS) - kinetic studies, screening tests, implementation of enzymatic reactions, product characterization (NMR, MS, GC/MS, UV/V): L. HECQUET (PR UCA) and F. CHARMANTRAY (CR CNRS)

• Pascal Institute (IP-UMR 6602), GePEB research axis: expertise in bioprocess engineering and glycosciences: - fractionation processes, biorefining, bioreactors, glycosciences: Philippe MICHAUD (PR Polytech) - large-scale expression of recombinant enzymes: Pascal DUBESSAY (MCF Polytech) - enzyme immobilization, analytical biochemistry (HPLC, HPAEC, FPLC): Guillaume PIERRE (MCF Polytech)

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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