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| DC Field | Value | Language |
|---|---|---|
| dc.creator | Ibarra, David | - |
| dc.creator | Chávez Uribe, María Isabel | - |
| dc.creator | Rencoret, Jorge | - |
| dc.creator | Río Andrade, José Carlos del | - |
| dc.creator | Gutiérrez Suárez, Ana | - |
| dc.creator | Romero Sánchez, Javier | - |
| dc.creator | Camarero, Susana | - |
| dc.creator | Martínez Hernández, María Jesús | - |
| dc.creator | Jiménez-Barbero, Jesús | - |
| dc.creator | Martínez, Ángel T. | - |
| dc.date | 2008-03-25T15:52:05Z | - |
| dc.date | 2008-03-25T15:52:05Z | - |
| dc.date | 2007 | - |
| dc.date.accessioned | 2017-01-31T01:00:55Z | - |
| dc.date.available | 2017-01-31T01:00:55Z | - |
| dc.identifier | Holzforschung 61(6): 634-646 (2007) | - |
| dc.identifier | 0018-3830 | - |
| dc.identifier | http://hdl.handle.net/10261/3303 | - |
| dc.identifier | http://dx.doi.org/10.1515/HF.2007.096 | - |
| dc.identifier | 1437-434X | - |
| dc.identifier.uri | http://dspace.mediu.edu.my:8181/xmlui/handle/10261/3303 | - |
| dc.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. | - |
| dc.description | Peer reviewed | - |
| dc.format | 466644 bytes | - |
| dc.format | application/pdf | - |
| dc.language | eng | - |
| dc.rights | openAccess | - |
| dc.subject | 2D-NMR | - |
| dc.subject | Enzymes | - |
| dc.subject | Eucalyptus globulus | - |
| dc.subject | FTIR | - |
| dc.subject | HMBC | - |
| dc.subject | HSQC | - |
| dc.subject | Laccase-mediator system | - |
| dc.subject | Paper pulp | - |
| dc.subject | Py-GC/MS | - |
| dc.subject | TCF bleaching | - |
| dc.title | Structural modification of eucalypt pulp lignin in a totally chlorine free bleaching sequence including a laccase-mediator stage | - |
| dc.type | Artículo | - |
| Appears in Collections: | Digital Csic | |
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