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International audience; Hybrid catalysis, which combines chemo-and biocatalytic benefits, is an efficient way to address green chemistry principles. 5-Hydroxymethylfurfural (HMF) is a versatile building block in numerous industrial applications. To date, few studies have described the production of its amine derivatives and their polymers. Finding a good methodology to directly transform HMF to 5-aminomethyl-2furancarboxylic acid (AMFC) therefore represents an important challenge. After selecting the best oxidation catalyst for HMF conversion to 5-aldehyde-2-furancarboxylic acid and immobilizing a transaminase onto a solid carrier, we implemented the first onepot/two-steps hybrid catalytic process to produce AMFC (77 % yield); this is the most efficient AMFC catalytic production method from HMF reported to date. This process also produced 2,5-furandicarboxylic acid (21 % yield) as a major secondary product that can be applied to polymer syntheses such as polyethylene furanoate. Herein, we report a novel way to access new biosourced polymers based on HMF oxidized and aminated derivatives.

International audience; Notably available from the cellulose contained in lignocellulosic biomass, glucose is a highly attractive substrate for eco-efficient processes towards high-value chemicals. A recent strategy for biomass valorization consists on combining biocatalysis and chemocatalysis to realise the so-called chemo-enzymatic or hybrid catalysis. Optimisation of the glucose conversion to 5-hydroxymethylfurfural (HMF) is the object of many research efforts. HMF can be produced by chemo-catalyzed fructose dehydration, while fructose can be selectively obtained from enzymatic glucose isomerization. Despite recent advances in HMF production, a fully integrated efficient process remains to be demonstrated. Our innovative approach consists on a continuous process involving enzymatic glucose isomerization, selective arylboronic-acid mediated fructose complexation/transportation, and chemical fructose dehydration to HMF. We designed a novel reactor based on two aqueous phases dynamically connected via an organic liquid membrane, which enabled substantial enhancement of glucose conversion (70%) while avoiding intermediate separation steps. Furthermore, in the as-combined steps, the use of an immobilized glucose isomerase and an acidic resin facilitates catalyst recycling

Notably available from the cellulose contained in lignocellulosic biomass, glucose is a highly attractive substrate for eco-efficient processes towards high-value chemicals. A recent strategy for biomass valorization consists on combining biocatalysis and chemocatalysis to realise the so-called chemo-enzymatic or hybrid catalysis. Optimisation of the glucose conversion to 5-hydroxymethylfurfural (HMF) is the object of many research efforts. HMF can be produced by chemo-catalyzed fructose dehydration, while fructose can be selectively obtained from enzymatic glucose isomerization. Despite recent advances in HMF production, a fully integrated efficient process remains to be demonstrated. Our innovative approach consists on a continuous process involving enzymatic glucose isomerization, selective arylboronic-acid mediated fructose complexation/transportation, and chemical fructose dehydration to HMF. We designed a novel reactor based on two aqueous phases dynamically connected via an organic liquid membrane, which enabled substantial enhancement of glucose conversion (70%) while avoiding intermediate separation steps. Furthermore, in the as-combined steps, the use of an immobilized glucose isomerase and an acidic resin facilitates catalyst recycling.

This multidisciplinary project was devoted to the discovery of new biocatalysts for the synthesis of chiral amines, through the screening of libraries of enzymes selected from the biodiversity. It involved the achievement of various tasks.The design and construction of three collections of transaminases, with a total of around 800 enzymes, was carried out within a strong collaboration with the Genoscope institute of Evry. We have developed novel efficient enzymatic assays allowing the high- throughput screening of the transaminase libraries and the detection, with high sensitivity, of new biocatalysts for a variety of transamination reactions. A rigorous statistical data analysis allowed highlighting a large set of hits, in which 24 transaminases were selected for further studies. After confirming the screening results, we have explored the substrate spectrum of the selected enzymes and studied the specific properties of some of them. Finally, we have demonstrated the usefulness of the new identified biocatalysts through their implementation for several applications. Some enzymes were used in an enzymatic cascade, whereas others allowed the synthesis of L- or D-homophénylalanine through an efficient innovative process.In addition to the multiple perspectives of application, this PhD work constitutes a valuable contribution to the fundamental knowledge about enzymatic transaminations., e travail de thèse pluridisciplinaire a eu pour objectif la découverte de nouveaux outils biocatalytiques pour la synthèse d’amines chirales, par criblage de banques d’enzymes issues de la biodiversité. Il a impliqué un ensemble de tâches diverses.Trois collections de transaminases, comptant un total d’environ 800 enzymes, ont été construites dans le cadre d’une collaboration étroite avec le Génoscope d’Evry. Nous avons mis au point différents tests d’activité originaux, qui ont permis un criblage haut- débit de ces banques de transaminases et la détection, très sensible, de nouveaux catalyseurs pour une grande variété de réactions de transamination. Un traitement statistique rigoureux des données a permis de révéler un ensemble de hits, au sein duquel 24 TA ont été sélectionnées pour des études plus approfondies. Après avoir confirmé les résultats du criblage, nous avons exploré plus en détail le spectre de substrats de ces enzymes et les propriétés spécifiques de certaines d’entre elles. Nous avons enfin démontré l’intérêt de ces nouveaux biocatalyseurs à travers des premières applications. Certaines TA ont ainsi pu être engagées dans une cascade enzymatique ou mises en œuvre dans un procédé innovant pour la synthèse des deux énantiomères de l’homophénylalanine.En plus d’offrir de nombreuses perspectives d’applications, ce travail de thèse représente une contribution notable à l’avancée des connaissances fondamentales sur les réactions de transamination enzymatique.