Lytic polysaccharide monooxygenases disrupt the cellulose fibers structure

Ana Villares Garicochea (1) , Céline Moreau (1) , Chloé Bennati-Granier (2) , Sonia Garajova (2) , Loic Foucat (1) , Xavier Falourd (1) , Bodo Saake (3) , Jean-Guy Berrin (2) , Bernard Cathala (1)

1 BIA - Unité de recherche sur les Biopolymères, Interactions Assemblages
2 BBF - Biodiversité et Biotechnologie Fongiques
3 Chemical Wood Technology

Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that breakdown recalcitrant polysaccharides such as cellulose. Here we investigate the action of LPMOs on cellulose fibers. After enzymatic treatment and dispersion, LPMO-treated fibers show intense fibrillation. Cellulose structure modifications visualized at different scales indicate that LPMO creates nicking points that trigger the disintegration of the cellulose fibrillar structure with rupture of chains and release of elementary nanofibrils. Investigation of LPMO action using solid-state NMR provides direct evidence of modification of accessible and inaccessible surfaces surrounding the crystalline core of the fibrils. The chains breakage likely induces modifications of the cellulose network and weakens fibers cohesion promoting their disruption. Besides the formation of new initiation sites for conventional cellulases, this work provides the first evidence of the direct oxidative action of LPMOs with the mechanical weakening of the cellulose ultrastructure. LPMOs can be viewed as promising biocatalysts for enzymatic modification or degradation of cellulose fibers.

Mots clés: activité lytique; monooxygénase; polysaccharide; fibre cellulosique; fibre de cellulose

Domaines: Ingénierie des aliments

Ana Villares Garicochea, Céline Moreau, Chloé Bennati-Granier, Sonia Garajova, Loic Foucat, et al.. Lytic polysaccharide monooxygenases disrupt the cellulose fibers structure. Scientific Reports, 2017, 7, ⟨10.1038/srep40262⟩. ⟨hal-01595678⟩