Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

Contreras, Sofía; Gaspar, Armindo R.; Guerra, Anderson; Lucia, Lucian A.; Argyropoulos, Dimitris S.

doi:10.1021/bm800673a

Cited by 89 publications

(93 citation statements)

References 34 publications

(109 reference statements)

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“…Data acquisition and processing were performed by ASTRA 6.1.4 software (Wyatt Technologies). The averaged molecular weights of the lignin samples were calculated from the MALLS data using the dn/dc (RI increment) value of 0.18 mL g -1 obtained from the literature [36]. All the samples were diluted with water and filtered through a 0.2-μm polytetrafluoroethylene (PTFE) disposable membrane prior to injection.…”

Section: Methodsmentioning

confidence: 99%

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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The production of carboxylic acids by partial wet oxidation of alkali lignin was studied experimentally. The factors influencing the different types of products, their yields and concentrations were investigated. Formic, acetic, succinic, oxalic, and glutaconic acid were the main identified products. Both the temperature and oxygen partial pressure are shown to have direct effects on the product yields whereas the lignin concentration has an indirect effect. At low lignin concentrations, the yield of products was relatively high. However, at higher concentrations, the yield decreased. By measuring the lignin molecular weight distributions, it is shown that this decrease is linked to repolymerization/condensation reactions of lignin fragments which compete with oxidative lignin depolymerization.

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Section: Methodsmentioning

confidence: 99%

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

et al. 2015

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“…Furthermore, softwood lignins displayed a greater tendency for reversible self-assembly compared to hardwood lignins (Table 2) [129]. The effect of environmental factors such as ionic strength, pH, temperature, solvent, time and aging effects upon lignin self-assembly were studied by changes to the molecular mass using the light scattering techniques of multiangle laser light scattering (MALLS) and differential refractometry (DR) [130]. Lignin molecular weight distributions were related to guaiacyl and syringyl content and structural variations such as hardwood lignin being more linear than softwood lignin (Table 2).…”

Section: Supramolecular Ligninmentioning

confidence: 99%

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

et al. 2010

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Phenylpropanoid metabolism yields a mixture of monolignols that undergo chaotic, non-enzymatic reactions such as free radical polymerization and spontaneous selfassembly in order to form the polyphenolic lignin which is a barrier to cost-effective lignocellulosic biofuels. Post-synthesis lignin integration into the plant cell wall is unclear, including how the hydrophobic lignin incorporates into the wall in an initially hydrophilic milieu. Self-assembly, self-organization and aggregation give rise to a complex, 3D network of lignin that displays randomly branched topology and fractal properties. Attempts at isolating lignin, analogous to archaeology, are instantly destructive and nonrepresentative of in planta. Lack of plant ligninases or enzymes that hydrolyze specific bonds in lignin-carbohydrate complexes (LCCs) also frustrate a better grasp of lignin. Supramolecular self-assembly, nano-mechanical properties of lignin-lignin, ligninpolysaccharide interactions and association-dissociation kinetics affect biomass deconstruction and thereby cost-effective biofuels production. OPEN ACCESSMolecules 2010, 15 8642

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“…This is particularly true for kraft lignins. The MALS instruments with a red laser (633–690 nm) equipped with narrow band filters can be completely sufficient only in case of selected lignosulfonates and mildly extracted lignins, which have a reduced number of fluorescent groups 32, 33, 34, 35…”

Section: Introductionmentioning

confidence: 99%

Getting Closer to Absolute Molar Masses of Technical Lignins

et al. 2018

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Determination of molecular weight parameters of native and, in particular, technical lignins are based on size exclusion chromatography (SEC) approaches. However, no matter which approach is used, either conventional SEC with a refractive index detector and calibration with standards or multi‐angle light scattering (MALS) detection at 488 nm, 633 nm, 658 nm, or 690 nm, all variants can be severely erroneous. The lack of calibration standards with high structural similarity to lignin impairs the quality of the molar masses determined by conventional SEC, and the typical fluorescence of (technical) lignins renders the corresponding MALS data rather questionable. Application of MALS detection at 785 nm by using an infrared laser largely overcomes those problems and allows for a reliable and reproducible determination of the molar mass distributions of all types of lignins, which has been demonstrated in this study for various and structurally different analytes, such as kraft lignins, milled‐wood lignin, lignosulfonates, and biorefinery lignins. The topics of calibration, lignin fluorescence, and lignin UV absorption in connection with MALS detection are critically discussed in detail, and a reliable protocol is presented. Correction factors based on MALS measurements have been determined for commercially available calibration standards, such as pullulan and polystyrene sulfonate, so that now more reliable mass data can be obtained also if no MALS system is available and these conventional calibration standards have to be resorted to.

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Propensity of Lignin to Associate: Light Scattering Photometry Study with Native Lignins

Cited by 89 publications

References 34 publications

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

Alkaline Partial Wet Oxidation of Lignin for the Production of Carboxylic Acids

Supramolecular Self-Assembled Chaos: Polyphenolic Lignin’s Barrier to Cost-Effective Lignocellulosic Biofuels

Getting Closer to Absolute Molar Masses of Technical Lignins

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