title: Condensed lignin structures and re-localization achieved at high severities in autohydrolysis of Eucalyptus globulus wood and their relationship with cellulose accessibility.
abstract: Eucalyptus globulus wood was subjected to autohydrolysis pretreatment at different severity factors. The pretreated materials were enzymatically saccharified at a substrate load of 10% (w/v) using a cellulase enzyme complex. Around 82-95% of original glucans were retained in the pretreated material, and the enzymatic hydrolysis yields ranged from 58% to 90%. The chemical and structural changes in the pretreated materials were investigated by microscopic (SEM, LSCM) and spectroscopic (2D-HSQC NMR and FT-IR) techniques. 2D-NMR results showed a reduction in the amounts of β-O-4 aryl-ether linkages and suggested the presence of newly condensed structures of lignin in the biomass pretreated at the more severe conditions. Furthermore, the microscopic analysis showed that lignin migrates out of the cell wall and re-deposits in certain regions of the fibers at the more severe conditions to form droplet-like structures and expose the cellulose surface. These changes improved the glucose yield up to 69%, on dry wood basis.
authors: Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile. fabioaraya@udec.cl.|Centro de Biotecnología, Universidad de Concepción, Casilla 160-C, Concepción, Chile. fabioaraya@udec.cl.
authors: Fabio
authors: F
authors: Araya
authors: Centro de Biotecnología, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
authors: Eduardo
authors: E
authors: Troncoso
authors: Centro de Biotecnología, Universidad de Concepción, Casilla 160-C, Concepción, Chile.|Facultad de Ciencias Forestales, Universidad de Concepción, Concepción, Chile.
authors: Regis Teixeira
authors: RT
authors: Mendonça
authors: Facultad de Ciencias Químicas, Universidad de Concepción, Concepción, Chile.|Centro de Biotecnología, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
authors: Juanita
authors: J
authors: Freer
mesh_terms: D002482:Cellulose / Q000737:chemistry* / Q000378:metabolism; D005052:Eucalyptus / Q000737:chemistry*; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D014934:Wood / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002482:Cellulose; D008031:Lignin
keywords: HSQC 2D-NMR; autohydrolysis; enzymatic saccharification; lignin