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John Ralph - One of the best experts on this subject based on the ideXlab platform.
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Lignin structure and its engineering
Current Opinion in Biotechnology, 2019Co-Authors: John Ralph, Catherine Lapierre, Wout BoerjanAbstract:Studies on Lignin structure and its engineering are inextricably and bidirectionally linked. Perturbations of genes on the Lignin biosynthetic pathway may result in striking compositional and structural changes that in turn suggest novel approaches for altering Lignin and even 'designing' the polymer to enhance its value or with a view toward its simpler removal from the cell wall polysaccharides. Basic structural studies on various native Lignins increasingly refine our knowledge of Lignin structure, and examining Lignins in different species reveals the extent to which evolution and natural variation have resulted in the incorporation of 'non-traditional' phenolic monomers, including phenolics from beyond the monolignol biosynthetic pathway. As a result, the very definition of Lignin continues to be expanded and refined.
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manipulation of guaiacyl and syringyl monomer biosynthesis in an arabidopsis cinnamyl alcohol dehydrogenase mutant results in atypical Lignin biosynthesis and modified cell wall structure
The Plant Cell, 2015Co-Authors: Nickolas A Anderson, John Ralph, Yuki Tobimatsu, Eduardo Ximenes, Bryon S Donohoe, Peter N Ciesielski, Michael R LadischAbstract:Modifying Lignin composition and structure is a key strategy to increase plant cell wall digestibility for biofuel production. Disruption of the genes encoding both cinnamyl alcohol dehydrogenases (CADs), including CADC and CADD, in Arabidopsis thaliana results in the atypical incorporation of hydroxycinnamaldehydes into Lignin. Another strategy to change Lignin composition is downregulation or overexpression of ferulate 5-hydroxylase (F5H), which results in Lignins enriched in guaiacyl or syringyl units, respectively. Here, we combined these approaches to generate plants enriched in coniferaldehyde-derived Lignin units or Lignins derived primarily from sinapaldehyde. The cadc cadd and ferulic acid hydroxylase1 (fah1) cadc cadd plants are similar in growth to wild-type plants even though their Lignin compositions are drastically altered. In contrast, disruption of CAD in the F5H-overexpressing background results in dwarfism. The dwarfed phenotype observed in these plants does not appear to be related to collapsed xylem, a hallmark of many other Lignin-deficient dwarf mutants. cadc cadd, fah1 cadc cadd, and cadd F5H-overexpressing plants have increased enzyme-catalyzed cell wall digestibility. Given that these CAD-deficient plants have similar total Lignin contents and only differ in the amounts of hydroxycinnamaldehyde monomer incorporation, these results suggest that hydroxycinnamaldehyde content is a more important determinant of digestibility than Lignin content.
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coexistence but independent biosynthesis of catechyl and guaiacyl syringyl Lignin polymers in seed coats
The Plant Cell, 2013Co-Authors: Yuki Tobimatsu, John Ralph, Fang Chen, Jin Nakashima, Lisa Jackson, Richard A. Dixon, Luis EscamillatrevinoAbstract:Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl Lignin homopolymer (C Lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C Lignin or traditional guaiacyl/syringyl (G/S) Lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C Lignin together with traditional G/S Lignins in their seed coats. Solution-state NMR analyses, along with an in vitro Lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C Lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C Lignin appears successively after G Lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G Lignin precursors. This study exemplifies the flexible biosynthesis of different types of Lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells.
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Coexistence but Independent Biosynthesis of Catechyl and Guaiacyl/Syringyl Lignin Polymers in Seed Coats
The Plant Cell, 2013Co-Authors: Yuki Tobimatsu, Fang Chen, Jin Nakashima, Luis Escamilla-trevino, Lisa Jackson, Richard A. Dixon, John RalphAbstract:Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl Lignin homopolymer (C Lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C Lignin or traditional guaiacyl/syringyl (G/S) Lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C Lignin together with traditional G/S Lignins in their seed coats. Solution-state NMR analyses, along with an in vitro Lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C Lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C Lignin appears successively after G Lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G Lignin precursors. This study exemplifies the flexible biosynthesis of different types of Lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells.
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Chapter 6 – Lignin
Cereal Straw as a Resource for Sustainable Biomaterials and Biofuels, 2010Co-Authors: John RalphAbstract:Publisher Summary Lignin, as a natural polymer, exists in all terrestrial plants, although some aquatic organisms may contain Lignin or “Lignin-like” components. Lignin molecules, starting with dimerization of two monolignol radicals, grow via cross coupling between a monolignol radical and the previously formed dimeric or oligomeric lignol radicals. Lignins are plant polymers made from phenylpropanoid building units. They contain most of the wood methoxyl content. Lignins are resistant to acid hydrolysis, readily oxidized, soluble in hot alkaline and bisulfite, and readily condensed with phenols or thiols. Many attempts have been made to define Lignin or Lignins based on the constitution, structural features, and mechanism of formation. The problem of lack of precise definition for Lignin is associated with its nature: no regularly repeating multi-unit structures have been found, and compositions and structures of Lignin vary depending on their origins. Any simplified definition would risk excluding aspects of Lignin. Lignins in grass plant cell walls are much more complex than those in wood. Lignin precursors, monolignols, are more diverse in grasses, and the biosynthetic pathways for monolignols are still not quite clear as that for monolignols in woods and dicots. Because of the intimate associations between polysaccharides and Lignins in grasses, better procedures for isolating Lignins from grass plant cell walls are still needed to better understand structures of grass Lignins, as well as their cross-linking to polysaccharides. In grasses, cross-link polysaccharides and Lignins form so-called Lignin–hydroxycinnamate–polysaccharide complex, which severely decreases the digestibility of cell wall polysaccharides by ruminants.
Alain Castellan - One of the best experts on this subject based on the ideXlab platform.
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Adding value to Lignins isolated from sugarcane bagasse and Miscanthus
Industrial Crops and Products, 2013Co-Authors: C. G. Da Silva, Elisabete Frollini, Stéphane Grelier, Frédérique Ham-pichavant, Alain CastellanAbstract:Attempt to depolymerize industrial organosolv Lignin (from sugarcane bagasse) and Lignins extracted from sugarcane bagasse and Miscanthus fibers (isolated by a soda/anthraquinone process) in presence of an anthraquinone acid catalyst (AQCOOH) was described. With the aim to substitute formaldehyde by glutaraldehyde, a dialdehyde that can be obtained from natural sources, Lignins were reacted with glutaraldehyde and studied as phenolic-type resins for thermosets. The reactions were predominantly analyzed be SEC and P-31 NMR spectrometry. The Organosolv Lignin-glutaraldehyde resin was used to prepare a composite reinforced with sugarcane bagasse fibers. Control samples were also prepared; specifically, composites based on phenol-formaldehyde and organosolv Lignin-formaldehyde matrices. The results of the impact and the flexural strength tests of these composites showed that the organosolv Lignin and glutaraldehyde can successfully replace phenol and formaldehyde, respectively.
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sugar cane bagasse and curaua Lignins oxidized by chlorine dioxide and reacted with furfuryl alcohol characterization and stability
Polymer Degradation and Stability, 2004Co-Authors: William Hoareau, Wanderson G Trindade, Bertrand Siegmund, Alain Castellan, Elisabete FrolliniAbstract:Abstract Sugar cane bagasse and curaua acidolysis Lignins were used to get a better understanding of the mechanism involved in a new chemical modification of sugar cane bagasse and curaua fibres, consisting in a selective oxidation of Lignin by chlorine dioxide and reacting some of the created unsaturated units (quinones or muconic derivatives) with furfuryl alcohol (FA). The objective of the treatment was to create a fibre coating increasing compatibility between fibres and phenolic resins in composites. The Lignins were reacted with chlorine dioxide to oxidize the phenolic units of the polymer and then treated with furfuryl alcohol. Weight percent gain of 14% and 10% were obtained for sugar cane bagasse and curaua, respectively. 1 H and 31 P NMR, as well as FT-IR results showed that bagasse Lignin had more guaiacyl than syringyl units and the reverse for curaua Lignin. 1 H NMR of oxidized Lignins revealed a decrease of the aromatic and methoxy content after the ClO 2 oxidation, due to partial degradation of the macromolecule. Thermal analysis showed that sugar cane Lignin decomposes at lower temperature than curaua Lignin, partly due to the high content of condensed structural units present in curaua Lignin. Condensed units decompose at higher temperatures than uncondensed ones. The reaction of oxidized Lignin with FA shifted the decomposition exotherm to lower temperature for both curaua and sugar cane bagasse Lignins, due to the modification introduced into their structures.
Yuki Tobimatsu - One of the best experts on this subject based on the ideXlab platform.
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manipulation of guaiacyl and syringyl monomer biosynthesis in an arabidopsis cinnamyl alcohol dehydrogenase mutant results in atypical Lignin biosynthesis and modified cell wall structure
The Plant Cell, 2015Co-Authors: Nickolas A Anderson, John Ralph, Yuki Tobimatsu, Eduardo Ximenes, Bryon S Donohoe, Peter N Ciesielski, Michael R LadischAbstract:Modifying Lignin composition and structure is a key strategy to increase plant cell wall digestibility for biofuel production. Disruption of the genes encoding both cinnamyl alcohol dehydrogenases (CADs), including CADC and CADD, in Arabidopsis thaliana results in the atypical incorporation of hydroxycinnamaldehydes into Lignin. Another strategy to change Lignin composition is downregulation or overexpression of ferulate 5-hydroxylase (F5H), which results in Lignins enriched in guaiacyl or syringyl units, respectively. Here, we combined these approaches to generate plants enriched in coniferaldehyde-derived Lignin units or Lignins derived primarily from sinapaldehyde. The cadc cadd and ferulic acid hydroxylase1 (fah1) cadc cadd plants are similar in growth to wild-type plants even though their Lignin compositions are drastically altered. In contrast, disruption of CAD in the F5H-overexpressing background results in dwarfism. The dwarfed phenotype observed in these plants does not appear to be related to collapsed xylem, a hallmark of many other Lignin-deficient dwarf mutants. cadc cadd, fah1 cadc cadd, and cadd F5H-overexpressing plants have increased enzyme-catalyzed cell wall digestibility. Given that these CAD-deficient plants have similar total Lignin contents and only differ in the amounts of hydroxycinnamaldehyde monomer incorporation, these results suggest that hydroxycinnamaldehyde content is a more important determinant of digestibility than Lignin content.
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Coexistence but Independent Biosynthesis of Catechyl and Guaiacyl/Syringyl Lignin Polymers in Seed Coats
The Plant Cell, 2013Co-Authors: Yuki Tobimatsu, Fang Chen, Jin Nakashima, Luis Escamilla-trevino, Lisa Jackson, Richard A. Dixon, John RalphAbstract:Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl Lignin homopolymer (C Lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C Lignin or traditional guaiacyl/syringyl (G/S) Lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C Lignin together with traditional G/S Lignins in their seed coats. Solution-state NMR analyses, along with an in vitro Lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C Lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C Lignin appears successively after G Lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G Lignin precursors. This study exemplifies the flexible biosynthesis of different types of Lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells.
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coexistence but independent biosynthesis of catechyl and guaiacyl syringyl Lignin polymers in seed coats
The Plant Cell, 2013Co-Authors: Yuki Tobimatsu, John Ralph, Fang Chen, Jin Nakashima, Lisa Jackson, Richard A. Dixon, Luis EscamillatrevinoAbstract:Lignins are phenylpropanoid polymers, derived from monolignols, commonly found in terrestrial plant secondary cell walls. We recently reported evidence of an unanticipated catechyl Lignin homopolymer (C Lignin) derived solely from caffeyl alcohol in the seed coats of several monocot and dicot plants. We previously identified plant seeds that possessed either C Lignin or traditional guaiacyl/syringyl (G/S) Lignins, but not both. Here, we identified several dicot plants (Euphorbiaceae and Cleomaceae) that produce C Lignin together with traditional G/S Lignins in their seed coats. Solution-state NMR analyses, along with an in vitro Lignin polymerization study, determined that there is, however, no copolymerization detectable (i.e., that the synthesis and polymerization of caffeyl alcohol and conventional monolignols in vivo is spatially and/or temporally separated). In particular, the deposition of G and C Lignins in Cleome hassleriana seed coats is developmentally regulated during seed maturation; C Lignin appears successively after G Lignin within the same testa layers, concurrently with apparent loss of the functionality of O-methyltransferases, which are key enzymes for the conversion of C to G Lignin precursors. This study exemplifies the flexible biosynthesis of different types of Lignin polymers in plants dictated by substantial, but poorly understood, control of monomer supply by the cells.
Catherine Lapierre - One of the best experts on this subject based on the ideXlab platform.
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Lignin structure and its engineering
Current Opinion in Biotechnology, 2019Co-Authors: John Ralph, Catherine Lapierre, Wout BoerjanAbstract:Studies on Lignin structure and its engineering are inextricably and bidirectionally linked. Perturbations of genes on the Lignin biosynthetic pathway may result in striking compositional and structural changes that in turn suggest novel approaches for altering Lignin and even 'designing' the polymer to enhance its value or with a view toward its simpler removal from the cell wall polysaccharides. Basic structural studies on various native Lignins increasingly refine our knowledge of Lignin structure, and examining Lignins in different species reveals the extent to which evolution and natural variation have resulted in the incorporation of 'non-traditional' phenolic monomers, including phenolics from beyond the monolignol biosynthetic pathway. As a result, the very definition of Lignin continues to be expanded and refined.
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Structural Redesigning Arabidopsis Lignins into Alkali-Soluble Lignins through the Expression of p- Coumaroyl-CoA:Monolignol Transferase PMT
Plant Physiology, 2016Co-Authors: Richard Sibout, Philippe Le Bris, Frédéric Legée, Laurent Cezard, Hugues Renault, Catherine LapierreAbstract:Grass Lignins can contain up to 10% to 15% by weight of p-coumaric esters. This acylation is performed on monolignols under the catalysis of p-coumaroyl-coenzyme A monolignol transferase (PMT). To study the impact of p-coumaroylation on lignification, we first introduced the Brachypodium distachyon Bradi2g36910 (BdPMT1) gene into Arabidopsis (Arabidopsis thaliana) under the control of the constitutive maize (Zea mays) ubiquitin promoter. The resulting p-coumaroylation was far lower than that of Lignins from mature grass stems and had no impact on stem Lignin content. By contrast, introducing either the BdPMT1 or the Bradi1g36980 (BdPMT2) gene into Arabidopsis under the control of the Arabidopsis cinnamate-4-hydroxylase promoter boosted the p-coumaroylation of mature stems up to the grass Lignin level (8% to 9% by weight), without any impact on plant development. The analysis of purified Lignin fractions and the identification of diagnostic products confirmed that p-coumaric acid was associated with Lignins. BdPMT1-driven p-coumaroylation was also obtained in the fah1 (deficient for ferulate 5-hydroxylase) and ccr1g (deficient for cinnamoyl-coenzyme A reductase) lines, albeit to a lower extent. Lignins from BdPMT1-expressing ccr1g lines were also found to be feruloylated. In Arabidopsis mature stems, substantial p-coumaroylation of Lignins was achieved at the expense of Lignin content and induced Lignin structural alterations, with an unexpected increase of Lignin units with free phenolic groups. This higher frequency of free phenolic groups in Arabidopsis Lignins doubled their solubility in alkali at room temperature. These findings suggest that the formation of alkali-leachable Lignin domains rich in free phenolic groups is favored when p-coumaroylated monolignols participate in lignification in a grass in a similar manner.
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Isolation of structurally distinct Lignin-carbohydrate fractions from maize stem by sequential alkaline extractions and endoglucanase treatment
Bioresource Technology, 2013Co-Authors: Mika Sipponen, Valerie Mechin, Catherine Lapierre, Stéphanie BaumbergerAbstract:Sequential fractionation of extractive-free maize stems was carried out using two mild alkaline extractions (0.5 and 2 M NaOH, 20 degrees C, 24 h) before and after endoglucanase treatment. This procedure provided two Lignin-carbohydrate fractions (LC1 and LC2) recovered after each alkali treatment. LC1 and LC2 contained 39% and 8% of the total Lignin amount, respectively. These two fractions contained structurally distinct Lignin molecules. While the content of resistant interunit bonds in Lignin was 77% in LC1, it was increased up to 98% in LC2. Not unexpectedly, both alkali-soluble fractions contained substantial amount of p-coumaric and ferulic acids ether-linked to Lignins. These results outline heterogeneity of maize stem Lignins related to fractionation of grass materials. (C) 2013 Elsevier Ltd. All rights reserved.
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In search of a maize ideotype for cell wall enzymatic degradability using histological and biochemical Lignin characterization.
Journal of Agricultural and Food Chemistry, 2005Co-Authors: Valerie Mechin, O. Argillier, Françoise Rocher, Y. Hébert, Brigitte Pollet, Yves Barriere, Isabelle Mila, Catherine LapierreAbstract:Grass cell wall degradability is conventionally related to the Lignin content and to the ferulic-mediated cross-linking of Lignins to polysaccharides. To better understand the variations in degradability, 22 maize inbred lines were subjected to image analyses of Fasga- and Maule-stained stem sections and to chemical analyses of Lignins and p-hydroxycinnamic acids. For the first time, the nearness of biochemical and histological estimates of Lignin levels was established. Combination of histological and biochemical traits could explain 89% of the variations for cell wall degradability and define a maize ideotype for cell wall degradability. In addition to a reduced Lignin level, such an ideotype would contain Lignins richer in syringyl than in guaiacyl units and preferentially localized in the cortical region rather than in the pith. Such enrichment in syringyl units would favor wall degradability in grasses, contrary to dicots, and could be related to the fact that grass syringyl units are noticeably p-coumaroylated. This might affect the interaction capabilities of Lignins and polysaccharides.
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Lignin structure in a mutant pine deficient in cinnamyl alcohol dehydrogenase
Journal of Agricultural and Food Chemistry, 2000Co-Authors: Catherine Lapierre, Igitte Polle, Joh Mackay, Ronald R SederoffAbstract:Cinnamyl alcohol dehydrogenase (CAD) activity is deficient in loblolly pine (Pinus taeda L.) harboring a mutated allele of the cad gene (cad-n1). We compared Lignin structure of CAD-deficient and wild-type pines, both types segregating within full-sib families obtained by controlled crosses. The type and frequency of Lignin building units and distribution of interunit bonds were determined from the GC−MS analysis of thioacidolysis monomers and dimers. While the Lignin content was only slightly reduced, the Lignin structure was dramatically modified by the mutation in both mature and juvenile trees. Lignins from CAD-deficient pine displayed unusually high levels of coniferaldehyde and dihydroconiferyl alcohol. In addition, biphenyl and biphenyl ether bonds were in large excess in these abnormal Lignins. These results suggest that the CAD-deficient pines efficiently compensate for the shortage in normal Lignin precursors by utilizing nontraditional wall phenolics to construct unusual Lignins particularly en...
Elisabete Frollini - One of the best experts on this subject based on the ideXlab platform.
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Adding value to Lignins isolated from sugarcane bagasse and Miscanthus
Industrial Crops and Products, 2013Co-Authors: C. G. Da Silva, Elisabete Frollini, Stéphane Grelier, Frédérique Ham-pichavant, Alain CastellanAbstract:Attempt to depolymerize industrial organosolv Lignin (from sugarcane bagasse) and Lignins extracted from sugarcane bagasse and Miscanthus fibers (isolated by a soda/anthraquinone process) in presence of an anthraquinone acid catalyst (AQCOOH) was described. With the aim to substitute formaldehyde by glutaraldehyde, a dialdehyde that can be obtained from natural sources, Lignins were reacted with glutaraldehyde and studied as phenolic-type resins for thermosets. The reactions were predominantly analyzed be SEC and P-31 NMR spectrometry. The Organosolv Lignin-glutaraldehyde resin was used to prepare a composite reinforced with sugarcane bagasse fibers. Control samples were also prepared; specifically, composites based on phenol-formaldehyde and organosolv Lignin-formaldehyde matrices. The results of the impact and the flexural strength tests of these composites showed that the organosolv Lignin and glutaraldehyde can successfully replace phenol and formaldehyde, respectively.
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sugar cane bagasse and curaua Lignins oxidized by chlorine dioxide and reacted with furfuryl alcohol characterization and stability
Polymer Degradation and Stability, 2004Co-Authors: William Hoareau, Wanderson G Trindade, Bertrand Siegmund, Alain Castellan, Elisabete FrolliniAbstract:Abstract Sugar cane bagasse and curaua acidolysis Lignins were used to get a better understanding of the mechanism involved in a new chemical modification of sugar cane bagasse and curaua fibres, consisting in a selective oxidation of Lignin by chlorine dioxide and reacting some of the created unsaturated units (quinones or muconic derivatives) with furfuryl alcohol (FA). The objective of the treatment was to create a fibre coating increasing compatibility between fibres and phenolic resins in composites. The Lignins were reacted with chlorine dioxide to oxidize the phenolic units of the polymer and then treated with furfuryl alcohol. Weight percent gain of 14% and 10% were obtained for sugar cane bagasse and curaua, respectively. 1 H and 31 P NMR, as well as FT-IR results showed that bagasse Lignin had more guaiacyl than syringyl units and the reverse for curaua Lignin. 1 H NMR of oxidized Lignins revealed a decrease of the aromatic and methoxy content after the ClO 2 oxidation, due to partial degradation of the macromolecule. Thermal analysis showed that sugar cane Lignin decomposes at lower temperature than curaua Lignin, partly due to the high content of condensed structural units present in curaua Lignin. Condensed units decompose at higher temperatures than uncondensed ones. The reaction of oxidized Lignin with FA shifted the decomposition exotherm to lower temperature for both curaua and sugar cane bagasse Lignins, due to the modification introduced into their structures.
