Chemical characterization of eucalypt pulp lignin during totally chlorine free bleaching including a laccase-mediator stage: 2D-NMR, FTIR and Py-GC/MS of enzymatically-isolated residual lignins.
Chemical modification of residual lignin isolated from eucalypt pulp after the different stages of a TCF sequence including a laccase-mediator stage was investigated by FTIR, Py-GC/MS and 2D-NMR (using HSQC, HSQC-TOCSY and HMBC). The enzymatic treatment resulted in strong oxidative modification of a lignin fraction, which could be removed under alkaline conditions enabling a final increase of brightness by hydrogen peroxide. In addition to changes in the ratios between syringyl and guaiacyl units and between β-O-4, syringaresinol and phenylcoumaran substructures, formation of acetosyringone and muconate terminal units were observed during the TCF sequence due to oxidative breakdown of lignin side-chains and aromatic nuclei respectively.
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| Main Authors: | , , , , , , , , |
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| Format: | comunicación de congreso biblioteca |
| Language: | English |
| Published: |
2006-08-27
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| Subjects: | Eucalyptus, Pulp, Lignin, TCF bleaching, Laccases, |
| Online Access: | http://hdl.handle.net/10261/86420 |
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