Biochemical and Structural Characterization of a Uronic Acid Oxidase from Citrus sinensis

Aldaric acids are attractive diacids that can be prepared by selective oxidation of carbohydrates. For this, effective biocatalysts are in demand. This work reports on the discovery, biochemical and structural characterization of a VAO-type flavin-containing carbohydrate oxidase from Citrus sinensis: URAOCs3. URAOCs3 could be overexpressed using prokaryotic and eukaryotic expression systems. Extensive biochemical characterization revealed that the enzyme displays a high thermostability and an exquisite selectivity for uronic acids, galacturonic acid and glucuronic acid. The enzyme was further investigated by determining the crystal structure. The selective oxidation of D-galacturonic acid in a complex mixture was demonstrated, showing how URAOCs3 was found to be highly effective in selectively producing galactaric acid while leaving other carbohydrates untouched. In addition to the specific discovery of URAOCs3, these findings suggest that plant proteomes can be an interesting source for new biocatalysts.</p

Synthesis and evaluation of C-glycosides as hydrotropes and solubilizing agents

International audienceThis work presents expeditious synthesis of C-glycoside amphiphiles in aqueous media from unprotected di- or mono-saccharides. A Horner-Wadsworth-Emmons/Michael addition/Barbier allylation sequence led to C-glycosides that exhibit hydrotropic properties. The hydrotropic and solubilizing properties of these homoallylic alcohols including a β-C-glycoside moiety as well as additional β-C-glycosidic ketones with a short (C7) alkyl chain are also described and compared with those of commercial O-glucoside references

Horner-Wadsworth-Emmons Reaction of Unprotected Sugars in Water or in the Absence of Any Solvent: One-Step Access to C-Glycoside Amphiphiles

International audienceThe synthesis of C-glycosides in water or in the absence of any solvent from free sugars and β-keto phosphonates is reported. The methodology permits a one-step access to C-glycoside amphiphiles in moderate-to-good yields. The selectivity (α/β and furanoside/pyranoside) is discussed and a process that leads to pure β-C-pyranosides is also described

Surface active compound

The present invention relates to novel surface active compounds based on polyhydroxy acids. The compounds are of formula (I), where X represents hydrogen or a cation; n is 4 and Y represents a group of formula (II) or formula (III), wherein at least one one of R1, R2 and R3 is a surfactant tail group, wherein the moiety represented by formula (Ι') represents the residue of galacturonic acid, and are generally easy to prepare by derivatization of polyhydroxy acids obtained from renewable resources such as, in particular, parenchymal plant materials. The invention relates to the surface active compounds, compositions comprising the same, methods of production and different uses of the surface active compounds. (l'), (l), (ll), (lll

Impacts de la crise de la Covid-19 sur les circuits courts de produits animaux : résultats d’enquêtes en début de pandémie

International audienceThe Covid-19 pandemic has been a major shock for contemporary societies and a source of major disruption of food systems. During the first months of the crisis (March-October 2020), members of the Réseau Mixte Technologique Alimentation Locale (Local Food Joint Technological Network) joined forces to conduct three nationwide surveys (citizens, advisers, producers) in order to understand the impacts of this crisis and sanitary associated measures on food systems, especially on short food supply chains. The article presents a summary of the data collected, focusing on the case of short chains for animal products. It shows how and under what conditions livestock farms involving these chains resisted, adapted and innovated during the first months of the pandemic. It emphasises the key role of collective action in the implementation of rapid solutions to the problems identified. While calling for an examination of whether these solutions were maintained thereafter, the article draws from them ways to consolidate short food chains of animal products and the resistance, adaptation and innovation capacities of the associated farm.La pandémie de la Covid-19 représente un choc majeur pour les sociétés contemporaines et une source de perturbations importantes pour les systèmes alimentaires. Lors des premiers mois de la crise (mars-octobre 2020), des membres du Réseau Mixte Technologique Alimentation locale se sont associés pour mener trois enquêtes (citoyens, accompagnateurs, producteurs) à l’échelle nationale afin de saisir les impacts de cette crise sur les systèmes alimentaires, en particulier sur les circuits courts. L’article propose une synthèse des données recueillies, en ciblant le cas des circuits courts de produits animaux. Il montre en quoi et à quelles conditions les exploitations d’élevage engagées dans ces modes de vente ont résisté, se sont adaptées et ont innové dans les premiers mois de la pandémie. Il souligne le rôle clé d’actions collectives dans la mise en place de solutions rapides aux problèmes identifiés. Tout en appelant à examiner si ces solutions ont été maintenues par la suite, l’article en tire des pistes d’action pour consolider les circuits courts de produits animaux et les capacités de résistance, d’adaptation et d’innovation des exploitations associées