Post-doctoral position 18 months Coupling chemistry to enzymatic action: structural changes towards new functionalities of vegetal fibers

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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

This postdoctoral position is part of the SmartCoupling project, funded by the PEPR B-Best, which aims to combine enzymes and chemistry to create sustainable and tailored tools for lignocellulosic biomass (LCB) fractionation and conversion into functionalized building blocks.

LCB can be viewed as a promising sustainable source of energy and materials. For this reason, its degradation has attracted much interest for the development of biofuels¹ as well as chemicals^{2, 3} and nanocelluloses.^{4, 5} The major bottleneck of lignocellulose utilization is its inherent recalcitrance, arising from the structural complexity leading to semi-crystalline arrangement of polysaccharides.⁶ For this reason, biomass fractionation makes necessary the addition of pretreatments including chemical, mechanical and/or enzymatic methods, which increase costs (energy) and environmental footprint (chemicals, water, waste). While humankind tries to overcome biomass recalcitrance in a sustainable way, Nature has already set it up by a battery of enzymes evolved by microorganisms for cell wall degradation. In this field, fungi secrete a number of enzymes, whose synergistic activity achieves lignocellulose degradation. Among these enzymes, lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that oxidatively cleave polysaccharides.⁷ LPMOs have already demonstrated a key role on cellulose fractionation.⁵ Thus, BIA and BBF have described for the first time the effect of LPMOs on the cellulose fiber, and we demonstrated that LPMOs attack the tension zones of the fiber and create nicking points, which facilitates fibrillation.^{4, 8} Although LPMO action on the cellulose fiber is promising, LCB is a much more complex substrate that may hinder their enzymatic action. 

The SmartCoupling project focuses on LPMOs as oxidative enzymes, and the chemical and mechanical pretreatments to disrupt the fiber structure in a controlled way. 

This postdoctoral position aims at investigating the role of biomass structural patterns (composition, morphology, accessible surface, water mobility…) on the controlled disruption to obtain cellulose micro and nanofibers. The purpose of the study is to get more insight into the biomass characteristics that drive the deconstruction by enzymes, chemistry or mechanical treatments. For this purpose, we propose the following objectives: 

1. To characterize different lignocellulosic biomasses by different approaches: composition, morphology, chemical reactivity, water uptake… to feed the database on biomass features. 
2. To treat biomasses by different approaches: enzymatic, chemical and mechanical, and to assess the structural changes imparted and the synergies between treatments.  
3. To define new approaches to fractionate lignocellulosic biomass.

 

Contract start: End of 2026 or Spring 2027

Supervision: INRAE BIA Nantes: Ana Villares; Céline Moreau (https://eng-ur-bia.angers-nantes.hub.inrae.fr/)

 

(1) Himmel, M. E.; Ding, S.-Y.; Johnson, D. K.; Adney, W. S.; Nimlos, M. R.; Brady, J. W.; Foust, T. D. Biomass recalcitrance: Engineering plants and enzymes for biofuels production. Science  2007, 315 (5813), 804–807. DOI: 10.1126/science.1137016.

(2) Bozell, J. J.; Petersen, G. R. Technology development for the production of biobased products from biorefinery carbohydrates-the US Department of Energy's "Top 10" revisited. Green Chem. 2010, 12 (4), 539–554. DOI: 10.1039/b922014c.

(3) Kumar, R.; Singh, S.; Singh, O. V. Bioconversion of lignocellulosic biomass: biochemical and molecular perspectives. Journal of Industrial Microbiology and Biotechnology 2008, 35 (5), 377–391. DOI: 10.1007/s10295-008-0327-8 (accessed 7/11/2023).

(4) Villares, A.; Moreau, C.; Bennati-Granier, C.; Garajova, S.; Foucat, L.; Falourd, X.; Saake, B.; Berrin, J. G.; Cathala, B. Lytic polysaccharide monooxygenases disrupt the cellulose fibers structure. Sci Rep 2017, 7, 40262. DOI: DOI: 10.1038/srep40262.

(5) Moreau, C.; Tapin-Lingua, S.; Grisel, S.; Gimbert, I.; Le Gall, S.; Meyer, V.; Petit-Conil, M.; Berrin, J. G.; Cathala, B.; Villares, A. Lytic polysaccharide monooxygenases (LPMOs) facilitate cellulose nanofibrils production. Biotechnol. Biofuels 2019, 12. DOI: 10.1186/s13068-019-1501-0.

(6) Marriott, P. E.; Gómez, L. D.; McQueen-Mason, S. J. Unlocking the potential of lignocellulosic biomass through plant science. New Phytologist 2016, 209 (4), 1366–1381. DOI: https://doi.org/10.1111/nph.13684.

(7) Bissaro, B.; Eijsink, V. G. H. Lytic polysaccharide monooxygenases: enzymes for controlled and site-specific Fenton-like chemistry. Essays in biochemistry 2023. DOI: 10.1042/ebc20220250  From NLM.

(8) Chemin, M.; Kansou, K.; Cahier, K.; Grellier, M.; Grisel, S.; Novales, B.; Moreau, C.; Villares, A.; Berrin, J. G.; Cathala, B. Optimized Lytic Polysaccharide Monooxygenase Action Increases Fiber Accessibility and Fibrillation by Releasing Tension Stress in Cellulose Cotton Fibers. Biomacromolecules  2023, 24 (7), 3246–3255. DOI: 10.1021/acs.biomac.3c00303.

Training and skills

We look for a candidate with initiative, creativity and team working ability, with a PhD in Chemistry, Physical Chemistry, Biochemistry or related. Expertise in lignocellulosic biomass will be highly considered, as well as in common characterization techniques in Physics and Nanotechnology (FTIR, UV-vis spectroscopy, NMR, EA) and specific techniques for the study of biopolymers (microscopy, AFM, TEM, Conductometry, DLS, X-Ray, birefringence, etc.). Knowledge of at least one of the following topics is particularly welcome: biopolymers, physical chemistry of biopolymers. 

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.

How to apply

Send a brief CV (maximum 2 pages) and a cover letter to Céline Moreau (celine.moreau@inrae.fr) and Ana Villares (ana.villares@inrae.fr) including two references for possible recommendation.