title: Oxalic acid: a microbial metabolite of interest for the pulping industry.
abstract: Oxalate is a common metabolite produced by almost all plant-pathogenic fungi. The degradation of cell wall from poplar chips and poplar sawdust by oxalate is reviewed here. Oxalate treatments decrease slightly the amount of sugars constituting hemicelluloses, but only in fibres and not in sawdust or wood chips. The examination of the cell wall ultrastructure of wood chips by transmission electron microscopy (TEM) after polysaccharide staining showed a characteristic fading of the staining of the S1/S2 and S2/S3 transition areas, supporting the idea that reactivity and organization of polysaccharides had changed after the oxalate treatments. Finally, all these changes enhanced the ability of the wood chips to be defibrated by a thermomechanical (TMP) process, as well as the further refining of the pulps. Looking at the fiber surface, it became apparent that fracture areas during the TMP pulping had moved toward the S2 layer, explaining why defibrating and refining occurred more easily, with less energy input in the process.
authors.affiliation: STORA-ENSO, 62112 Corbéhem, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Meyer-Pinson
authors.forename: Katia
authors.initials: K
authors.lastname: Ruel
authors.forename: François
authors.initials: F
authors.lastname: Gaudard
authors.forename: Gérard
authors.initials: G
authors.lastname: Valtat
authors.forename: Michel
authors.initials: M
authors.lastname: Petit-Conil
authors.forename: Bernard
authors.initials: B
authors.lastname: Kurek
mesh_terms: D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism*; D005658:Fungi / Q000378:metabolism; D007221:Industry / Q000379:methods; D008855:Microscopy, Electron, Scanning; D019815:Oxalic Acid / Q000378:metabolism* / Q000494:pharmacology; D014934:Wood
chemical_list: D019815:Oxalic Acid