Analysis of Lignin Products by Fluorescence Spectroscopy

Lundquist, Knut; Josefsson, Björn; Nyquist, Gunnar

doi:10.1515/hfsg.1978.32.1.27

Cited by 79 publications

(40 citation statements)

References 3 publications

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“…The exact origin of autofluorescence is not clear. It has been shown however, that residual aromatic compounds such as lignin and lignin derivatives in processed wood pulps can fluoresce when excited with ultra-violet light (Lundquist et al 1978). In c Zoom-in view of one particle, showing such surface features as pores and criss-crossing fibers and d where nano-meter scale pores are clearly visible addition, these compounds inside various structures of the pretreated wood behave as a single fluorochrome species (Li and Reeve 2004).…”

Section: Resultsmentioning

confidence: 99%

Observing Thermobifida fusca cellulase binding to pretreated wood particles using time-lapse confocal laser scanning microscopy

et al. 2011

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We report on studies of Thermobifida fusca cellulases Cel5A, Cel6B and Cel9A binding to pretreated wood particles using Confocal Laser Scanning Microscopy (CLSM). Hydro-thermal pretreated wood particles were immobilized on borosilicate substrates before fluorescently-labeled cellulase solutions at various concentrations were added. Time-lapse CLSM revealed that cellulases Cel5A, Cel6B and Cel9A quickly bound to certain areas of wood particles, slowly diffused into and adsorbed to less accessible areas, but showed little affinity for other areas of the wood. Cellulase-to-substrate association constants were estimated using a transient enzyme binding kinetics model, and were found to be in agreement with published values. In order to accurately account for the fluorescence signal of labeled enzyme mixed with wood autofluorescence, we also developed a spectral deconvolution method to separate signals from multiple fluorochromes.

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Section: Resultsmentioning

confidence: 99%

Observing Thermobifida fusca cellulase binding to pretreated wood particles using time-lapse confocal laser scanning microscopy

et al. 2011

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“…It is the proportion of incident combining eqs. [3] and [4], and rearranging: light reflected from an optically thick sample, i.e., R, = Is,Iinl Iin. R, changes with chlorite treatment.…”

Section: Wavelength (Nm)mentioning

confidence: 99%

“…Fluorescence emission has been observed from a wide variety of pulps (1, 2) and lignin components (3,4). Reductive treatments with compounds such as sodium borohydride result in an apparent increase in fluorescence intensity and a blue shift in emission, whereas oxidative reactions under irradiation with ultraviolet light or treatment with sodium periodate produce decreases and red shifts in emission.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence spectroscopy of mechanical pulps III: Effect of chlorite delignification

Olmstead¹,

Zhu²,

Gray³

1995

Can. J. Chem.

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Many paper and wood samples fluoresce, but the sources of the emission are not well understood. Fluorescence excitation and emission spectra of paper sheets prepared from thermomechanical pulp (TMP) and bleached chernithermomechanical pulp (BCTMP) showed that the emission from the BCTMP was significantly higher than that from the TMP. Removing almost all of the lignin from both pulps by means of an acid chlorite treatment did not reduce the fluorescence significantly. By means of an approximate correction for changes in sheet reflectivity caused by the chlorite treatment, the fluorescence intensity was found to increase with lignin removal. Clearly, fluorescence is not simply related to lignin content.Key words: wood pulp, lignin, cellulose, fluorescence spectra, acid chlorite delignification.

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“…The analysis of fluorescent spectra of polymeric molecules such as lignin is complex, since they may contain different fluorophores. Therefore, different model compounds are used in order to reveal spectroscopic properties of lignin [10][11][12][13]. Further, by using fluorescence spectroscopy and appropriate mathematical methods for deconvolution of emission spectra into individual components, it is possible to get better insight into the structural characteristics of the molecule, namely to estimate the number and nature of fluorophores [14,15].…”

Section: Introductionmentioning

confidence: 99%

Structural Differences Between Lignin Model Polymers Synthesized from Various Monomers

Djikanović¹,

Simonović²,

Savić³

et al. 2012

J Polym Environ

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In a plant cell wall, lignin is synthesized from several monomeric precursors, combined in various ratios. The variation in monomer type and quantity enables multifunctional role of lignin in plants. Thus, it is important to know how different combinations of lignin monomers impact variability of bond types and local structural changes in the polymer. Lignin model polymers are a good model system for studies of relation between variations of the starting monomers and structural variations within the polymer. We synthesized lignin model polymers from three monomers, CF-based on coniferyl alcohol and ferulic acid in monomer proportions 5:1 and 10:1 (w/w), CPbased on coniferyl alcohol and p-coumaric acid in proportion 10:1 (w/w) and CA-based on pure coniferyl alcohol. We studied structural modifications in the obtained polymers, by combining fluorescence microscopy and spectroscopy, FT-IR and Raman spectroscopy, in parallel with determination of polymers' molecular mass distribution. The differences in the low M w region of the distribution curves of the 10:1 polymers in comparison with the CA polymer may be connected with the increased content of C=C bonds and decreased content of condensed structures, as observed in FT-IR spectra and indicated by the analysis of fluorescence spectra. The 5:1 CF polymer contains a different type of structure in comparison with the 10:1 CF polymers, reflected in its simpler M w distribution, higher homogeneity of the fluorescence emitting structures and in the appearance of a new high-wavelength emission component. We propose that this component may originate from p-conjugated chains, which are longer in this polymer. The results are a contribution to the understanding of the involvement of structural variations of lignin polymers in the cell wall structural plasticity.

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Analysis of Lignin Products by Fluorescence Spectroscopy

Cited by 79 publications

References 3 publications

Observing Thermobifida fusca cellulase binding to pretreated wood particles using time-lapse confocal laser scanning microscopy

Observing Thermobifida fusca cellulase binding to pretreated wood particles using time-lapse confocal laser scanning microscopy

Fluorescence spectroscopy of mechanical pulps III: Effect of chlorite delignification

Structural Differences Between Lignin Model Polymers Synthesized from Various Monomers

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