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Studies of the chemoenzymatic modification of cellulosic pulps by the laccase-TEMPO system
11th EWLP, Hamburg, Germany, August 16–19, 2010
-
Ilabahen Patel
Veröffentlicht/Copyright:
25. Februar 2011
Abstract
The chemoenzymatic modification of cellulosic pulps by the laccase-mediator system (LMS) consisting of laccase (EC 1.10.3.2) and the 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) has been investigated. The reaction proceeds under mild aqueous conditions (sodium citrate buffer pH 6, 30°C) and introduces primarily aldehyde groups into cellulose so that carboxyl groups amount to one-third to one-fifth of the carbonyl groups only. LMS treatment caused uniform oxidation of the material, also in the high-molecular weight area, which is a non-typical behavior compared to other chemical oxidations of cellulose. Treatment of the pulp only with TEMPO or only with laccase caused no changes whatsoever, whereas treatment with the TEMPO-derived oxoammonium ion (in the absence of laccase) introduced carbonyl groups into the pulp, but no carboxyls. This chemoenzymatic approach was compared to the well-known chemical approach by means of TEMPO and hypohalite. Both approaches yielded comparable distributions of functional groups at the low oxidation degrees studied, indicating a similar reaction mechanism with the TEMPO-derived oxoammonium ion being the actual oxidant. The laccase is able to generate this oxoammonium ion, which in turn oxidized the 6-hydroxymethyl group into the corresponding aldehyde.
Keywords: carbonyl content; carboxyl content; cellulose; gel permeation chromatography (GPC); laccase; laccase-mediator system (LMS); TEMPO oxidation
Received: 2010-9-24
Accepted: 2010-11-9
Published Online: 2011-02-25
Published Online: 2011-02-25
Published in Print: 2011-06-01
©2011 by Walter de Gruyter Berlin Boston
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Artikel in diesem Heft
- Editorial
- EWLP 2010, 16th–19th August 2010, Hamburg, Germany
- Review
- Bio based fuels and fuel additives from lignocellulose feedstock via the production of levulinic acid and furfural
- Original Papers
- Optimization of steam pretreatment conditions for enzymatic hydrolysis of poplar wood
- Fungal pretreatment of pine wood to reduce the emission of volatile organic compounds
- Dilute acid pretreatment of starch-containing rice hulls for ethanol production
- Studies of the chemoenzymatic modification of cellulosic pulps by the laccase-TEMPO system
- Development of an integrated thermal and enzymatic hydrolysis for lignocellulosic biomass in fixed-bed reactors
- A larch based biorefinery: pre-extraction and extract fermentation to lactic acid
- Lignins as agents for bio-protection of wood
- Isolation and characterization of the phenolic fractions of wood pyrolytic oil
- Purification of Eucalyptus globulus water prehydrolyzates using the HiTAC process (high-temperature adsorption on activated charcoal)
- Disintegration and dissolution kinetics of wood chips in ionic liquids
- Ionic liquids as media for biomass processing: opportunities and restrictions
- Autohydrolysis of birch wood
- Solvent extraction as a means of preparing homogeneous lignin fractions
- Conditioning of SO2-ethanol-water spent liquor from spruce for the production of chemicals by ABE fermentation
- Total mass balances of SO2-ethanol-water (SEW) fractionation of forest biomass
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 1. Results from direct analyses
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 2: Advanced methods for the detailed characterization of lignin oxidation mechanisms
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 3. Reaction pathways and modeling
- Simplified determination of total lignin content in kraft lignin samples and black liquors
- Xylan deposition onto eucalypt pulp fibers during oxygen delignification
- Dissolution of dissolving pulp in alkaline solvents after steam explosion pretreatments
- Structure and antioxidant activity of diarylheptanoids extracted from bark of grey alder (Alnus incana) and potential of biorefinery-based bark processing of European trees
- Short Note
- Binding affinities of different metal ions to unbleached hardwood kraft pulp
- Meetings
- Meetings
Schlagwörter für diesen Artikel
carbonyl content;
carboxyl content;
cellulose;
gel permeation chromatography (GPC);
laccase;
laccase-mediator system (LMS);
TEMPO oxidation
Artikel in diesem Heft
- Editorial
- EWLP 2010, 16th–19th August 2010, Hamburg, Germany
- Review
- Bio based fuels and fuel additives from lignocellulose feedstock via the production of levulinic acid and furfural
- Original Papers
- Optimization of steam pretreatment conditions for enzymatic hydrolysis of poplar wood
- Fungal pretreatment of pine wood to reduce the emission of volatile organic compounds
- Dilute acid pretreatment of starch-containing rice hulls for ethanol production
- Studies of the chemoenzymatic modification of cellulosic pulps by the laccase-TEMPO system
- Development of an integrated thermal and enzymatic hydrolysis for lignocellulosic biomass in fixed-bed reactors
- A larch based biorefinery: pre-extraction and extract fermentation to lactic acid
- Lignins as agents for bio-protection of wood
- Isolation and characterization of the phenolic fractions of wood pyrolytic oil
- Purification of Eucalyptus globulus water prehydrolyzates using the HiTAC process (high-temperature adsorption on activated charcoal)
- Disintegration and dissolution kinetics of wood chips in ionic liquids
- Ionic liquids as media for biomass processing: opportunities and restrictions
- Autohydrolysis of birch wood
- Solvent extraction as a means of preparing homogeneous lignin fractions
- Conditioning of SO2-ethanol-water spent liquor from spruce for the production of chemicals by ABE fermentation
- Total mass balances of SO2-ethanol-water (SEW) fractionation of forest biomass
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 1. Results from direct analyses
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 2: Advanced methods for the detailed characterization of lignin oxidation mechanisms
- Lignin oxidation mechanisms under oxygen delignification conditions. Part 3. Reaction pathways and modeling
- Simplified determination of total lignin content in kraft lignin samples and black liquors
- Xylan deposition onto eucalypt pulp fibers during oxygen delignification
- Dissolution of dissolving pulp in alkaline solvents after steam explosion pretreatments
- Structure and antioxidant activity of diarylheptanoids extracted from bark of grey alder (Alnus incana) and potential of biorefinery-based bark processing of European trees
- Short Note
- Binding affinities of different metal ions to unbleached hardwood kraft pulp
- Meetings
- Meetings
