PhD student in glycobiology (M/F)

Job Description

Thesis Subject

Thesis project :
Dynamics of lignin acylation in poplar and Miscanthus

Thesis project description:
Lignins are among the main components of biomass and are obtained as by-products of the pulp and paper industry and second-generation biorefineries. New extraction processes are now emerging, and these compounds, initially regarded as waste and mainly used for heat production, are attracting increasing interest due to their chemical composition and abundance. Indeed, the valorisation of lignins would clearly contribute to building a more sustainable economy based on carbon derived from plant resources, as an alternative to applications relying on fossil oil, thereby generating growing interest from academia, industry and public sector stakeholders. In this context, the LILLEGNIN project aims to establish a complete value chain dedicated to lignin valorisation at the Lille site. The project brings together complementary areas of expertise such as the biology of plant-based raw materials, innovative lignin extraction and (bio)catalytic processing, as well as various innovative pathways for value creation in the fields of textiles, fire-retardant materials, biofuels and electronics. The Structural and Functional Glycobiology Unit (UGSF, University of Lille) is involved in the project due to its expertise in studying the dynamics of biosynthesis and the incorporation of molecules into different types of biopolymers. The plant secondary cell wall is a composite material comprising a polysaccharide matrix that contains, in particular, lignins. Our biological and biochemical approaches enable a better understanding of the interactions and interdependencies between its components and, consequently, a better understanding of their extractability. Among the various parameters that influence these interactions, the presence of acyl groups on lignins will have a significant influence, thereby facilitating their extraction. Lignin acylation is found in all angiosperms but is absent in gymnosperms. However, their precise role is not yet well understood. These acyl groups sometimes enable the formation of complexes between lignins and parietal polysaccharides, thereby stabilising the three-dimensional structure of the cell wall. Consequently, access to hydrolases will be affected, leading to variable degradation of the polysaccharides. The work will take place at the UGSF, located on the Cité Scientifique campus in Villeneuve d'Ascq (59). The PhD project will be structured around various objectives. The initial step will involve characterising the plant material, consisting of poplar seedlings to be grown on-site (greenhouse complex, University of Lille) and various Miscanthus genotypes, which will be grown in open-field conditions at the INRAE site in Estrées Mons. Lignins will be quantified and characterised using standard chemical techniques following storage periods of varying lengths. Plants grown under controlled conditions will be subjected to thermal stress (cold) and analysed in the same way. In parallel, the synthesis of chemical reporters mimicking acylated precursors (p-coumarate for Miscanthus and p-hydroxybenzoate for poplar) will be carried out chemically, and where appropriate, enzymatically. These reporters must incorporate a bioorthogonal tag allowing for the subsequent ligation of a fluorophore via click chemistry. Finally, these reporters will be incorporated into histological sections of cultivated plants as described above. The dynamics of their incorporation into the various plant samples will be assessed by confocal microscopy. This will enable us to assess (1) the spatiotemporal nature of the incorporation of acylated precursors within the tissues of the various model plants, as well as (2) the influence of biomass storage on the enzymatic activities responsible for this, and finally (3) the effect of abiotic stress on these activities.

Your Work Environment

This work will be carried out within the BIG (Biological Interaction of Glycans) team at the UGSF (UMR CNRS 8576, University of Lille). The PhD student (M/F) will receive tailored supervision, opportunities to develop new technical and analytical skills, as well as support to expand their scientific network and strengthen their publication record.

Constraints and risks

May involve travel for conferences or collaborative projects. Standard risks associated with working in a biochemistry laboratory, including exposure to chemicals, biological agents and extreme temperatures, as well as prolonged work at a computer screen.

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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