Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose
Eucalyptus globulus wood chips were subjected to autohydrolysis pretreatment at 175ºC at three different residence times. Part of the recovered solids were submitted to alkaline extraction with NaOH solution to remove leachable lignin. The chemical composition of the fibrous material was analyzed by HPLC, Py-GCMS and 2D-NMR HSQC, while morphological changes were evaluated by SEM and LSCM. The pretreated materials were hydrolyzed with cellulases at a substrate loading of 10% (w/v) for up to 72 h. Glucose yields (based on dry wood) obtained in the enzymatic hydrolysis ranged between 38% and 65%, depending on reaction time in the autohydrolysis pretreatment. After the alkaline extraction, no significant change was observed in the yields in the enzymatic hydrolysis at 72 h, but at the lower severities, the initial rates of saccharification increased. The main effect of the hydrothermal pretreatment was removal of hemicelluloses, resulting in enriched cellulose pulps. SEM and LSCM images of the hydrothermal pretreated samples showed a disruption of the fiber surface, mainly in those samples obtained at the higher severity. Py-GC/MS and HSQC analysis showed that no major changes in the lignin structure occurred in the samples obtained by autohydrolysis and further alkaline extraction. By autohydrolysis at the higher severity (So=4.02), the lateral chains in lignin were cleaved and the formation of lignin droplets was observed. Hemicelluloses removal and lignin redeposition as droplets in certain regions of the fiber surface was associated with the higher accessibility of cellulose and the yield increase of the enzymatic hydrolysis.
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Subjects: | Eucalyptus globulus, Autohydrolysis, Alkaline extraction, lignin, enzymatic hydrolysis, |
Online Access: | http://hdl.handle.net/10261/123782 |
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dig-irnas-es-10261-1237822016-08-29T11:10:50Z Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose Araya, Fabio Troncoso, Eduardo Teixeira Mendonça, Regis Freer, Juanita Rencoret, Jorge Río Andrade, José Carlos del Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis Eucalyptus globulus wood chips were subjected to autohydrolysis pretreatment at 175ºC at three different residence times. Part of the recovered solids were submitted to alkaline extraction with NaOH solution to remove leachable lignin. The chemical composition of the fibrous material was analyzed by HPLC, Py-GCMS and 2D-NMR HSQC, while morphological changes were evaluated by SEM and LSCM. The pretreated materials were hydrolyzed with cellulases at a substrate loading of 10% (w/v) for up to 72 h. Glucose yields (based on dry wood) obtained in the enzymatic hydrolysis ranged between 38% and 65%, depending on reaction time in the autohydrolysis pretreatment. After the alkaline extraction, no significant change was observed in the yields in the enzymatic hydrolysis at 72 h, but at the lower severities, the initial rates of saccharification increased. The main effect of the hydrothermal pretreatment was removal of hemicelluloses, resulting in enriched cellulose pulps. SEM and LSCM images of the hydrothermal pretreated samples showed a disruption of the fiber surface, mainly in those samples obtained at the higher severity. Py-GC/MS and HSQC analysis showed that no major changes in the lignin structure occurred in the samples obtained by autohydrolysis and further alkaline extraction. By autohydrolysis at the higher severity (So=4.02), the lateral chains in lignin were cleaved and the formation of lignin droplets was observed. Hemicelluloses removal and lignin redeposition as droplets in certain regions of the fiber surface was associated with the higher accessibility of cellulose and the yield increase of the enzymatic hydrolysis. The financial support from Fondecyt (grant 1110828), Conicyt (PhD fellowship 63100148), Conicit Costa Rica (PhD fellowship FI-59-2010), Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), Seville and DOE Great Lakes Bioenergy Research Center (DOE Office of Science BER DE-FC02-07ER64494) is acknowledged. Peer reviewed 2015 artículo http://purl.org/coar/resource_type/c_6501 Journal of the Chilean Chemical Society 60, 2954-2960 (2015) http://hdl.handle.net/10261/123782 en Sí open |
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Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis |
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Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis Araya, Fabio Troncoso, Eduardo Teixeira Mendonça, Regis Freer, Juanita Rencoret, Jorge Río Andrade, José Carlos del Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
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Eucalyptus globulus wood chips were subjected to autohydrolysis pretreatment at 175ºC at three different residence times. Part of the recovered solids were submitted to alkaline extraction with NaOH solution to remove leachable lignin. The chemical composition of the fibrous material was analyzed by HPLC, Py-GCMS and 2D-NMR HSQC, while morphological changes were evaluated by SEM and LSCM. The pretreated materials were hydrolyzed with cellulases at a substrate loading of 10% (w/v) for up to 72 h. Glucose yields (based on dry wood) obtained in the enzymatic hydrolysis ranged between 38% and 65%, depending on reaction time in the autohydrolysis pretreatment. After the alkaline extraction, no significant change was observed in the yields in the enzymatic hydrolysis at 72 h, but at the lower severities, the initial rates of saccharification increased. The main effect of the hydrothermal pretreatment was removal of hemicelluloses, resulting in enriched cellulose pulps. SEM and LSCM images of the hydrothermal pretreated samples showed a disruption of the fiber surface, mainly in those samples obtained at the higher severity. Py-GC/MS and HSQC analysis showed that no major changes in the lignin structure occurred in the samples obtained by autohydrolysis and further alkaline extraction. By autohydrolysis at the higher severity (So=4.02), the lateral chains in lignin were cleaved and the formation of lignin droplets was observed. Hemicelluloses removal and lignin redeposition as droplets in certain regions of the fiber surface was associated with the higher accessibility of cellulose and the yield increase of the enzymatic hydrolysis. |
format |
artículo |
topic_facet |
Eucalyptus globulus Autohydrolysis Alkaline extraction lignin enzymatic hydrolysis |
author |
Araya, Fabio Troncoso, Eduardo Teixeira Mendonça, Regis Freer, Juanita Rencoret, Jorge Río Andrade, José Carlos del |
author_facet |
Araya, Fabio Troncoso, Eduardo Teixeira Mendonça, Regis Freer, Juanita Rencoret, Jorge Río Andrade, José Carlos del |
author_sort |
Araya, Fabio |
title |
Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
title_short |
Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
title_full |
Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
title_fullStr |
Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
title_full_unstemmed |
Structural characteristics and distribution of lignin in Eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
title_sort |
structural characteristics and distribution of lignin in eucalyptus globulus pulps obtained by a combined autohydrolysis/alkaline extraction process for enzymatic saccharification of cellulose |
url |
http://hdl.handle.net/10261/123782 |
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