Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage
Modification of eucalypt pulp residual lignin in a totally chlorine free (TCF) bleaching sequence including a laccase-mediator stage, in combination with previous oxygen delignification and subsequent peroxide bleaching, was investigated and compared with a chemical TCF sequence. The enzymatic treatment resulted in a strong oxidative modification, as shown by lignin unit 13C2,6-1H2,6 correlations in HSQC 2D-NMR spectra and presence of oxidized pyrolysis markers. The frequency of inter-unit linkages in residual lignin was also modified, as shown by different side-chain 13C-1H correlations. Moreover, H2,6 correlations with side-chain carbons in HMBC spectra revealed the presence of Cα keto and carboxyl groups in lignin from the oxygen-delignified and especially from the enzymatically-treated pulp, together with normal (Cα-hydroxylated) lignin units. Moreover, the results obtained showed that most of this oxidatively-altered lignin is removed under the alkaline conditions used in the peroxide stage. In this way, the pulp kappa number decreased, and the final residual lignin was more structurally-related to that found before the oxidative stages (although with lower content of resinol structures, and higher presence of aryl-aryl ether structures and carboxyl-bearing terminal units). However, the action of hydrogen peroxide is required to attain the high brightness, over 91% ISO, found in final pulp after the enzyme-containing TCF sequence.
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Format: | artículo biblioteca |
Language: | English |
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2007
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Subjects: | 2D NMR, Enzymes, Eucalyptus globulus, FTIR, HMBC, HSQC, Laccase-mediator system, Paper pulp, Py-GC/MS, TCF bleaching, |
Online Access: | http://hdl.handle.net/10261/3303 |
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dig-irnas-es-10261-33032020-11-13T13:29:45Z Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage Ibarra, David Chávez Uribe, María Isabel Rencoret, Jorge Río Andrade, José Carlos del Gutiérrez Suárez, Ana Romero Sánchez, Javier Camarero, Susana Martínez, María Jesús Jiménez-Barbero, Jesús Martínez, Ángel T. 2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching Modification of eucalypt pulp residual lignin in a totally chlorine free (TCF) bleaching sequence including a laccase-mediator stage, in combination with previous oxygen delignification and subsequent peroxide bleaching, was investigated and compared with a chemical TCF sequence. The enzymatic treatment resulted in a strong oxidative modification, as shown by lignin unit 13C2,6-1H2,6 correlations in HSQC 2D-NMR spectra and presence of oxidized pyrolysis markers. The frequency of inter-unit linkages in residual lignin was also modified, as shown by different side-chain 13C-1H correlations. Moreover, H2,6 correlations with side-chain carbons in HMBC spectra revealed the presence of Cα keto and carboxyl groups in lignin from the oxygen-delignified and especially from the enzymatically-treated pulp, together with normal (Cα-hydroxylated) lignin units. Moreover, the results obtained showed that most of this oxidatively-altered lignin is removed under the alkaline conditions used in the peroxide stage. In this way, the pulp kappa number decreased, and the final residual lignin was more structurally-related to that found before the oxidative stages (although with lower content of resinol structures, and higher presence of aryl-aryl ether structures and carboxyl-bearing terminal units). However, the action of hydrogen peroxide is required to attain the high brightness, over 91% ISO, found in final pulp after the enzyme-containing TCF sequence. Peer reviewed 2008-03-25T15:52:05Z 2008-03-25T15:52:05Z 2007 artículo http://purl.org/coar/resource_type/c_6501 Holzforschung 61(6): 634-646 (2007) 0018-3830 http://hdl.handle.net/10261/3303 10.1515/HF.2007.096 1437-434X en open 466644 bytes application/pdf |
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2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching 2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching |
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2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching 2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching Ibarra, David Chávez Uribe, María Isabel Rencoret, Jorge Río Andrade, José Carlos del Gutiérrez Suárez, Ana Romero Sánchez, Javier Camarero, Susana Martínez, María Jesús Jiménez-Barbero, Jesús Martínez, Ángel T. Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
description |
Modification of eucalypt pulp residual lignin in a totally chlorine free (TCF) bleaching sequence including a laccase-mediator stage, in combination with previous oxygen delignification and subsequent peroxide bleaching, was investigated and compared with a chemical TCF sequence. The enzymatic treatment resulted in a strong oxidative modification, as shown by lignin unit 13C2,6-1H2,6 correlations in HSQC 2D-NMR spectra and presence of oxidized pyrolysis markers. The frequency of inter-unit linkages in residual lignin was also modified, as shown by different side-chain 13C-1H correlations. Moreover, H2,6 correlations with side-chain carbons in HMBC spectra revealed the presence of Cα keto and carboxyl groups in lignin from the oxygen-delignified and especially from the enzymatically-treated pulp, together with normal (Cα-hydroxylated) lignin units. Moreover, the results obtained showed that most of this oxidatively-altered lignin is removed under the alkaline conditions used in the peroxide stage. In this way, the pulp kappa number decreased, and the final residual lignin was more structurally-related to that found before the oxidative stages (although with lower content of resinol structures, and higher presence of aryl-aryl ether structures and carboxyl-bearing terminal units). However, the action of hydrogen peroxide is required to attain the high brightness, over 91% ISO, found in final pulp after the enzyme-containing TCF sequence. |
format |
artículo |
topic_facet |
2D NMR Enzymes Eucalyptus globulus FTIR HMBC HSQC Laccase-mediator system Paper pulp Py-GC/MS TCF bleaching |
author |
Ibarra, David Chávez Uribe, María Isabel Rencoret, Jorge Río Andrade, José Carlos del Gutiérrez Suárez, Ana Romero Sánchez, Javier Camarero, Susana Martínez, María Jesús Jiménez-Barbero, Jesús Martínez, Ángel T. |
author_facet |
Ibarra, David Chávez Uribe, María Isabel Rencoret, Jorge Río Andrade, José Carlos del Gutiérrez Suárez, Ana Romero Sánchez, Javier Camarero, Susana Martínez, María Jesús Jiménez-Barbero, Jesús Martínez, Ángel T. |
author_sort |
Ibarra, David |
title |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
title_short |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
title_full |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
title_fullStr |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
title_full_unstemmed |
Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
title_sort |
structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage |
publishDate |
2007 |
url |
http://hdl.handle.net/10261/3303 |
work_keys_str_mv |
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