Modification phenomena of solid-state lignin caused by electron-abstracting oxidative systems

Barsberg, Søren

doi:10.1016/s0003-9861(02)00225-4

Cited by 9 publications

(13 citation statements)

References 33 publications

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“…As confirmed by previous observations the lignin modification traverses several temporal phases 14. The 1 610 cm −1 positive signal, observed initially (15 min) and only for λ ex = 400 nm, are transient products, which are oxidized to other products as the reaction progresses to 1 h. The transient products could be cell wall lignin phenoxyl radicals, which have absorption bands in the 400–500 nm range15 similar to those observed for the initial modification by laccase‐ABTS (Figure 1).…”

Section: Discussionsupporting

confidence: 86%

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Structural Analysis of Lignin by Resonance Raman Spectroscopy

Barsberg¹,

Matousek

Towrie

2005

Macromolecular Bioscience

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Resonance Raman (RR) spectroscopy, combined with Kerr gated fluorescence rejection in the time domain, has recently elucidated lignin structure with unique sensitivity and selectivity. This promises structural studies of fluorescent natural macromolecules, such as lignin, which were previously not possible. Such studies rely on an improved understanding of the RR spectral behavior of lignin, which is today scarcely understood. We explain for the first time this behavior by a semi-empirical theory, and observe its pertinent features for lignin in vascular plants. We have used well-defined oxidative treatments as means of probing lignin structural elements, and show that RR sensitivity and selectivity depend crucially on excitation wavelength. Through the theory we relate these results to basic structural aspects of lignin. Spectra obtained by blue light laser excitation (400 nm) are dominated by low redox potential syringyl lignin groups, whereas lower photon energy (500 nm) decreases the selectivity markedly. RR bands depend on molecular structure but also on molecular environment. Thus charge transfer donor-acceptor interactions within lignin reduce the intensity of bands associated with electron rich moieties. New possibilities for basic and selective structural information on fluorescent natural materials, such as lignin, have thus appeared.

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Section: Discussionsupporting

confidence: 86%

“…Top, left: laccase‐ABTS, 10 min (F max ≈ 0.3) and 1 h treatments (F max ≈ 2.7). The dotted line is the absolute spectrum of unmodified control fibres relative to BaSO 4 100% reflectance standard (reproduced from ref 14…”

Section: Resultsmentioning

confidence: 99%

Structural Analysis of Lignin by Resonance Raman Spectroscopy

Barsberg¹,

Matousek

Towrie

2005

Macromolecular Bioscience

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“…The difference function DF (not shown) describes a broad strong absorption band at ;560 nm with a distinct shoulder at ;430 nm and is qualitatively identical to earlier ndings for laccase-ABTS. 1 The bene t of presenting IR and FT-Raman spectra as difference spectra is seen from Fig. 1, which depicts the three independent spectra S i (before normalization) of the comparison treatment together with those from the 8 h treatments with oxygen.…”

Section: Resultsmentioning

confidence: 99%

“…Even for the same type of reaction system, such as an enzyme-mediator treatment of a pulp, the distribution of reaction products, i.e., spectroscopic signal positions and their strengths, show distinct changes with treatment time. 1 Fourier transform (FT) Raman spectroscopy has recently appeared as a feasible technique for lignin characterization. [2][3][4][5] The often strong laser-induced uorescence of lignin has limited the possibility of obtaining good Raman signals using conventional techniques.…”

Section: Introductionmentioning

confidence: 99%

Fourier Transform Raman Difference Spectroscopy for Detection of Lignin Oxidation Products in Thermomechanical Pulp

Vester

Felby²,

Nielsen

et al. 2004

Appl Spectrosc

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Spruce thermomechanical pulp (TMP) was oxidized by the 2,2'azinobis-3-ethylbenzthiazoline-6-sulfonate cation radical (ABTS*+) in the presence and absence of oxygen. The pulp modification was monitored by Fourier transform (FT) Raman difference spectroscopy and other nondestructive spectroscopic methods. The ABTS*+ oxidative system resulted in modifications very similar to the laccase-ABTS-oxygen system, except for the FT-Raman results, which showed a difference in mechanisms attributed to a difference in produced Raman bands. Oxygen resulted in no oxygen-derived products, but only enhanced the production of a specific Raman band of several oxidation-produced bands. Detailed information on lignin reactions can be obtained from FT-Raman signals.

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“…ABTS (2,2´-azino-bis(3-ethylbenzo-thiazoline-6-sulphonic acid) has been shown to mediate electron abstraction between fibre lignin and laccase in qualitative difference in temporal phases than laccase does alone. Resulting distinguished lignin modifications may have consequences for subsequent fibre behaviour (Barsberg 2002). Lund & Felby (2001) applied a range of mediators in laccase-modification of spruce and pine fibres and found ABTS and PPT (phenothiazine-10-propionic acid) to be effective in enhancing wet tensile strength of paper handsheets made from the pulp.…”

Section: Homogenisationmentioning

confidence: 99%

Wood production, wood technology, and biotechnological impacts

Kües¹

2007

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Modification phenomena of solid-state lignin caused by electron-abstracting oxidative systems

Cited by 9 publications

References 33 publications

Structural Analysis of Lignin by Resonance Raman Spectroscopy

Structural Analysis of Lignin by Resonance Raman Spectroscopy

Fourier Transform Raman Difference Spectroscopy for Detection of Lignin Oxidation Products in Thermomechanical Pulp

Wood production, wood technology, and biotechnological impacts

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