Quantitative 31P NMR Spectroscopy of Lignins from Transgenic Poplars

Akim, Leonid G.; Argyropoulos, Dimitris S.; Jouanin, Lise; Leplé, Jean‐Charles; Pilate, Gilles; Pollet, Brigitte; Lapierre, Catherine

doi:10.1515/hf.2001.064

Cited by 46 publications

(47 citation statements)

References 9 publications

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“…Quantification was then carried out via peak integration using N-hydroxynaphthalimide as an internal standard. Details of signal acquisition, assignment, and integration can be found elsewhere (31)(32)(33).…”

Section: Resultsmentioning

confidence: 99%

Toward a Better Understanding of the Lignin Isolation Process from Wood

Guerra

Filpponen

Lucia

et al. 2006

J. Agric. Food Chem.

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210

213

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The recently developed protocol for isolating enzymatic mild acidolysis lignins (EMAL) coupled with the novel combination of derivatization followed by reductive cleavage (DFRC) and quantitative (31)P NMR spectroscopy were used to better understand the lignin isolation process from wood. The EMAL protocol is shown to offer access at lignin samples that are more representative of the overall lignin present in milled wood. The combination of DFRC/(31)P NMR provided a detailed picture on the effects of the isolation conditions on the lignin structure. More specifically, we have used vibratory and ball milling as the two methods of wood pulverization and have compared their effects on the lignin structures and molecular weights. Vibratory-milling conditions cause substantial lignin depolymerization. Lignin depolymerization occurs via the cleavage of uncondensed beta-aryl ether linkages, while condensed beta-aryl ethers and dibenzodioxocins were found to be resistant to such mechanical action. Condensation and side chain oxidations were induced mechanochemically under vibratory-milling conditions as evidenced by the increased amounts of condensed phenolic hydroxyl and carboxylic acid groups. Alternatively, the mild mechanical treatment offered by ball milling was found not to affect the isolated lignin macromolecular structure. However, the overall lignin yields were found to be compromised when the mechanical action was less intense, necessitating longer milling times under ball-milling conditions. As compared to other lignin preparations isolated from the same batch of milled wood, the yield of EMAL was about four times greater than the corresponding milled wood lignin (MWL) and about two times greater as compared to cellulolytic enzyme lignin (CEL). Molecular weight distribution analyses also pointed out that the EMAL protocol allows the isolation of lignin fractions that are not accessed by any other lignin isolation procedures.

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Section: Resultsmentioning

confidence: 99%

Toward a Better Understanding of the Lignin Isolation Process from Wood

Guerra

Filpponen

Lucia

et al. 2006

J. Agric. Food Chem.

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210

213

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“…[57][58][59] Ball-milled enzyme extracted lignin from P. deltoides was found to have 0.20 moles/C 9 phenolic OH groups, 1.18 moles/C 9 aliphatic OH, and 0.02 moles/C 9 COOH groups. 57 31 P NMR data from Wu and Argyropoulos 60 on P. tremuloides and Akim et al 59 on control and transgenic poplar lignin are summarized in Table 11. CAD and COMT down-regulation resulted in lignin with a lower amount of aliphatic OH and a higher condensed phenolic OH content than the control poplar lignin (Table 11).…”

Section: 58mentioning

confidence: 99%

“…CAD and COMT down-regulation resulted in lignin with a lower amount of aliphatic OH and a higher condensed phenolic OH content than the control poplar lignin (Table 11). 59 Genetic modifi cation of lignin content and composition in poplars S/G ratios increased slightly (from 1.6 to 2.0) from the pith …”

Section: 58mentioning

confidence: 99%

Poplar as a feedstock for biofuels: A review of compositional characteristics

Sannigrahi

Ragauskas

Tuskan³

2010

Biofuels Bioprod Bioref

593

422

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The growing demand for transportation fuels, along with concerns about the harmful effects of greenhouse gas emissions from the burning of fossil fuels, has assured a viable future for the development of alternative fuels from renewable resources, such as lignocellulosic biomass. The effi cient utilization of these biomass resources is critically dependant on the in-depth knowledge of their chemical constituents. This, together with the desired fuel properties, helps tailor the chemical and/or enzymatic processes involved in converting biomass to biofuels. Hybrid poplars are among the fastest growing temperate trees in the world and a very promising feedstock for biofuels and other value-added products. Sequencing of the poplar genome has paved the way for tailoring new cultivars and clones optimized for biofuels production. Our objective is to review published research on the composition of the key chemical constituents of hybrid poplar species used for biofuels. Biomass yields, elemental composition, carbohydrate and lignin content and composition are some of the characteristics reviewed, with emphasis on lignin structure. Genetic modifi cations used to alter lignin content and composition, with the aim of improving biofuels yields, are also examined.

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“…1 H-NMR: Varian INOVA300 FT-NMR spectrometer (300 MHz) in chloroform-d with tetramethylsilane as the internal standard (0.0 ppm). Quantitative 31 P-NMR analyses of S/G-(9:1)-DHPs were conducted according to Argyropoulos (1994), Granata and Argyropoulos (1995), and Akim et al (2001). Phosphitylations of the DHPs were carried out in anhydrous pyridine containing chrominium (III) acetylacetonate as a relaxation reagent by 2-chrolo-1,3,2-dioxaphospholane and 2-chrolo-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane with dimethyl-L-tartate and cyclohexanol as an internal standard, respectively.…”

Section: Structural Characterization Of Dhpsmentioning

confidence: 99%

Reactivity of syringyl quinone methide intermediates in dehydrogenative polymerization. Part 2: pH effect in horseradish peroxidase-catalyzed polymerization of sinapyl alcohol

et al. 2010

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The solvent pH effect in the horseradish peroxidase (HRP)-catalyzed polymerization of sinapyl alcohol (S-alc) and analogously, sinapyl alcohol g-O-glucoside (isosyringin, iso-S) was investigated particularly focusing on the behavior of syringyl-type quinone methide intermediates (S-type QMs) under acidic conditions. At first, the HRP-catalyzed polymerization of iso-S at pH 6.5-2.5, which produces watersoluble dehydrogenation polymer (DHP) intermediates in a homogeneous phase, was monitored by UV spectroscopy and gel permeation chromatography with photodiode array detection (GPC-PDA). Under acidic conditions at pH below 4.5, unstablilized S-type QMs from iso-S are rapidly quenched resulting in efficient productions of DHPs, although substantial loss of HRP activity and the resulting insufficient polymerization were inevitable at pH below 3.5. In addition, it was found that a small addition of guaiacyl-type comonomer (isoconiferin, iso-G) effectively promotes the polymerization of iso-S under acidic conditions, in which the comonomer serves as a radical mediator to facilitate the HRP-catalyzed oxidations of iso-S. Next, the HRP-catalyzed polymerization of S-alc at various pH values was conducted and the resulting DHPs were characterized by GPC and NMR measurements. The yields of isolated DHPs significantly increased as solvent pH decreased below 4.5. The structural analyses of the DHPs demonstrated that reaction selectivity of S-type QMs during the polymerization drastically changed at pH below 4.5: they react efficiently with water molecules as solvent leading to the formation of benzyl alcohol type b-O-4 substructures preferentially to the formation of a-O-aryl type substructures. Consequently, the data in this study demonstrated that acidic conditions at pH below 4.5 are favored in the dehydrogenative polymerization of S-alc from the viewpoint of the reactivity of S-type QMs.

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Quantitative 31P NMR Spectroscopy of Lignins from Transgenic Poplars

Cited by 46 publications

References 9 publications

Toward a Better Understanding of the Lignin Isolation Process from Wood

Toward a Better Understanding of the Lignin Isolation Process from Wood

Poplar as a feedstock for biofuels: A review of compositional characteristics

Reactivity of syringyl quinone methide intermediates in dehydrogenative polymerization. Part 2: pH effect in horseradish peroxidase-catalyzed polymerization of sinapyl alcohol

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