Lignin Carbohydrate Complex. Pt. IV. Lignin as Side Chain of the Carbohydrate in Björkman LCC

Yaku, Fumiko; Tanaka, Ryutaro; Koshijima, Tetsuo

doi:10.1515/hfsg.1981.35.4.177

Cited by 26 publications

(20 citation statements)

References 2 publications

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“…It is derived from three hydroxycinnamyl alcohols (p-coumaryl, coniferyl and sinapyl alcohols) by a dehydrogenating polymerization involving radical coupling [7]. Lignin is known to bind physically/chemically to cellulose/hemicellulose by covalent bonding such as benzyl-ether, benzyl-ester, and phenyl-glycoside bonds, forming lignin-carbohydrate complexes (LCC) in plant cell walls [8]. The lignin is separated from lignocellulosic materials by use of various methods.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of PLA–lignin bioplastics properties before and after accelerated weathering

Spiridon¹,

Leluk

Resmeriță³

et al. 2015

Composites Part B: Engineering

200

109

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Section: Introductionmentioning

confidence: 99%

Evaluation of PLA–lignin bioplastics properties before and after accelerated weathering

Spiridon¹,

Leluk

Resmeriță³

et al. 2015

Composites Part B: Engineering

200

109

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“…1 In addition, lignin is covalently linked to polysaccharides, forming a ligninhemicellulose network made up of benzyl-ether, [2][3][4] benzyl-ester, [5][6][7] and phenyl-glycoside bonds. 8,9 It provides mechanical support for plants, facilitates the transport of nutrients, and defends against attack from microorganisms.…”

Section: Introductionmentioning

confidence: 99%

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Sun

Zhai³

et al. 2008

J of Applied Polymer Sci

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Six lignin fractions from mild ball-milled Tamarix austromogoliac (TA) and Caragana sepium (CS) were sequentially isolated with 80% dioxane containing 0.05M HCl at 758C for 4 h, 50% aqueous ethanol containing 1M triethylamine at 708C for 4 h, and 8% aqueous NaOH at 458C for 3 h. The results showed that the successive treatments made it possible to isolate lignin from wood with a high yield and purity, in which 89.4 and 90.6% of the original lignin from TA and CS were released, respectively. The lignin fractions isolated with the three-step method were analyzed with Fourier transform infrared, 1 H-and 13 C-NMR, alkaline nitrobenzene oxidation, and gel permeation chromatography. It was found that the three lignin fractions isolated from TA were rich in syringyl units, and the molar ratio of the relatively total moles of vanillin, vanillic acid, and acetovanillin to the relatively total moles of syringaldehyde, syringic acid, and acetosyringone decreased from 1 : 2.6 to 1 : 3.2 to 1 : 3.6 in the lignin preparations, whereas this ratio in the corresponding lignin fractions isolated from CS was found to be 1.4 : 1, 1.1 : 1, and 1 : 1.4, respectively. More importantly, the results revealed that the sequential extractions of the mild ball-milled TA and CS with 80% acidic dioxane, 50% alkaline ethanol, and 8% aqueous NaOH under the conditions used did not significantly cleave the b-O-4 and a-O-4 linkages in lignin macromolecules.

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Section: Discussionmentioning

confidence: 71%

“…The most plausible explanation for the acquisition of alkali resistance is the formation of a quinone methide (Figure 7, structure 3), rapidly followed by nucleophilic attack by a sugar residue (structure 4), creating a p-hydroxybenzyl ether bond (structure 5). Analogous benzyl-sugar ether bonds, formed via quinone methide intermediates, have been reported in lignin structures (Yaku et al, 1981;Takahashi and Koshijima, 1988;Barakat et al, 2007). Compared with the two ester bonds (COO)) of structure 5, the benzyl ether bond is expected to be more resistant to mild alkali, albeit more alkali-labile (as in structure VIII of Enoki et al, 1983) than most other types of ether bond.…”

Section: Proposed Mechanism Of Formation Of Mild-alkali-stable Cross-mentioning

confidence: 88%

Extracellular cross‐linking of maize arabinoxylans by oxidation of feruloyl esters to form oligoferuloyl esters and ether‐like bonds

Burr

Fry²

2009

The Plant Journal

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SUMMARYPrimary cell walls of grasses and cereals contain arabinoxylans with esterified ferulate side chains, which are proposed to cross-link the polysaccharides during maturation by undergoing oxidative coupling. However, the mechanisms and control of arabinoxylan cross-linking in vivo are unclear. Non-lignifying maize (Zea mays L.) cell cultures were incubated with L-[1-3 H]arabinose or (E)-[U-14 C]cinnamate (radiolabelling the pentosyl and feruloyl groups of endogenous arabinoxylans, respectively), or with exogenous feruloyl-[ 3 H]arabinoxylans. The cross-linking rate of soluble extracellular arabinoxylans, monitored on Sepharose CL-2B, peaked suddenly and transiently, typically at $9 days after subculture. This peak was not associated with appreciable changes in peroxidase activity, and was probably governed by fluctuations in H 2 O 2 and/or inhibitors. De-esterified arabinoxylans failed to cross-link, supporting a role for the feruloyl ester groups. The cross-links were stable in vivo. Some of them also withstood mild alkaline conditions, indicating that they were not (only) based on ester bonds; however, most were cleaved by 6 M NaOH, which is a property of p-hydroxybenzyl-sugar ether bonds. Cross-linking of [ 14 C]feruloyl-arabinoxylans also occurred in vitro, in the presence of endogenous peroxidases plus exogenous H 2 O 2 . During cross-linking, the feruloyl groups were oxidized, as shown by ultraviolet spectra and thin-layer chromatography. Esterified diferulates were minor oxidation products; major products were: (i) esterified oligoferulates, released by treatment with mild alkali; and (ii) phenolic components attached to polysaccharides via relatively alkali-stable (ether-like) bonds. Thus, feruloyl esters participate in polysaccharide cross-linking, but mainly by oligomerization rather than by dimerization. We propose that, after the oxidative coupling, strong p-hydroxybenzyl-polysaccharide ether bonds are formed via quinone-methide intermediates.

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Lignin Carbohydrate Complex. Pt. IV. Lignin as Side Chain of the Carbohydrate in Björkman LCC

Cited by 26 publications

References 2 publications

Evaluation of PLA–lignin bioplastics properties before and after accelerated weathering

Evaluation of PLA–lignin bioplastics properties before and after accelerated weathering

Comparative study of three lignin fractions isolated from mild ball‐milled Tamarix austromogoliac and Caragana sepium

Extracellular cross‐linking of maize arabinoxylans by oxidation of feruloyl esters to form oligoferuloyl esters and ether‐like bonds

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