Structural Studies of Lignin Isolation Procedures by<sup>13</sup>C NMR

Bartuska, Victor J.; Maciel, Gary E.; Bolker, H. I.; Fleming, B. I.

doi:10.1515/hfsg.1980.34.6.214

Cited by 79 publications

(31 citation statements)

References 9 publications

(5 reference statements)

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“…And the peak of 103 ppm is due to nonprotonated resonance peaks from tannin and lignin; 124 and 150 ppm originate from C-, H-substituted aromatic-C and Osubstituted aromatic-C, respectively. Generally, the phenolic-C of 150 ppm occurs in the process of lignin decomposing (Bartuska et al, 1980), however, the 150 ppm resonance peak is very weak in this experiment and this may indicate that the resonance peak of 150 ppm mainly comes from some decomposition material of straw or stubble but not lignin, or some phenolic-C coming from decomposing materials of lignin. The chemical shift around 173 ppm attributes to carboxyl-C of the amide and polypeptide.…”

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confidence: 64%

Tillage impacts on the fractions and compositions of soil organic carbon

Zhao

Wang

et al. 2012

Geoderma

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This study aimed to reveal the impacts of tillage systems on the fractions (active, slow, and passive carbon) and chemical compositions of soil organic carbon (SOC). A long-term (26 years) tillage experiment in northeast China examined no-tillage (NT), plowing tillage (PT) and deep loosing (DL). The soil samples (from a depth of 0-20 cm) were wet-sieved into five aggregate classes (1000-2000 μm, 500-1000 μm, 250-500 μm, 50-250 μm, and b50 μm). The active carbon (C) and passive C were detected in the 500-1000 μm, 250-500 μm, and 50-250 μm aggregates, and the chemical compositions of SOC in micro-aggregates (b 250 μm) and macro-aggregates (>250 μm) were assessed by CPMAS 13 C NMR. Macro-aggregates contained more SOC concentration than micro-aggregates. However, PT resulted in a greater SOC concentration in 50-500 μm aggregates. NT and DL increased the active C and decreased the slow C in 500-1000 μm aggregates, whereas PT showed the inverse. The 13 C NMR spectrum demonstrated that NT increased alkyl-C content, PT obtained a higher carbonyl-C concentration, and DL gained a greater O-alkyl-C concentration. Moreover, evaluating the impacts of tillage systems on the complexity revealed that the most complicated structure was presented in NT, the least in PT, whereas DL had an intermediate effect. Active C contains C2-C6 carbohydrate and anomeric C (C1) polysaccharides, slow C consists of aldehyde-C, ketonic-C and quinone-C, and the passive C is enriched in aromatic-C. In conclusion, long-term tillage systems significantly affected the fractions and compositions of SOC, with NT stabilizing the SOC.

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confidence: 64%

Tillage impacts on the fractions and compositions of soil organic carbon

Zhao

Wang

et al. 2012

Geoderma

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“…Nevertheless, the juvenile mutant appeared to have a similar or higher methoxyl content. The difference in the ratio of the peaks at 151 and 148 ppm can be explained at least in part by the incorporation of the 4-hydroxy-2-methoxybenzaldehyde subunit (9), the aromatic C-O (C 2 and C 4 ) signals of which are shifted downfield.…”

Section: Resultsmentioning

confidence: 99%

“…Due to this intimate association, quantitative isolation of the complete lignin polymer has proven to be impossible. As a result, most structural information has come from isolated lignin preparations, specifically solution-state nuclear magnetic resonance (NMR) of milled wood lignin (MWL) (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19), which is typically only 15-20% of the native lignin and is extracted as a dioxane-soluble, low molecular weight material (20).…”

Section: Introductionmentioning

confidence: 99%

Differences between Lignin in Unprocessed Wood, Milled Wood, Mutant Wood, and Extracted Lignin Detected by ¹³C Solid-State NMR

Mao

Holtman

Scott

et al. 2006

J. Agric. Food Chem.

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Solid-state 13C nuclear magnetic resonance (NMR) spectroscopy was applied to intact and isolated loblolly pine wood samples to identify potential structural changes induced by tree age, milling, lignin extraction, or naturally occurring mutations. Special attention was paid to ketone and aldehyde as well as nonpolar alkyl groups, which could be observed at low concentrations (<2 in 1000 C) using improved spinning-sideband suppression with gated decoupling. Carbonyl structures were present in intact wood, and there are more keto groups than aldehydes. Their concentrations increased from juvenile to mature wood and with milling time, whereas extraction did not alter the C=O fraction. Significant amounts of aldehyde and dihydroconiferyl alcohol residues were present in coniferyl aldehyde dehydrogenase-deficient wood, confirming solution-state NMR spectra of the corresponding lignin. These results demonstrate the utility of solid-state NMR as an assay for changes in the lignin structure of genetically modified plants.

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“…[14] Solid-state cross polarization magic angle spinning (CPMAS) 13 C NMR is the traditional method of choice for solid lignin preparations. [14,18,19] This technique has also been used to analyze the structures of DHPs and natural lignin in samples whose side chains have been labeled with 13 C. [14,16] Lignin side chains may have various oxidation states, displaying a combination of hydroxyl, carbonyl, and carboxyl groups, and its monomers are bonded together in irregular patterns. Furthermore, lignin can display different stereochemical arrangements, as up to two asymmetric centers on each of its side chain units are possible.…”

Section: Introductionmentioning

confidence: 99%

NMR Structural Characterization ofQuercus alba(White Oak) Degraded by the Brown Rot Fungus,Laetiporus sulphureus

Koenig

Sleighter

Salmon

et al. 2010

Journal of Wood Chemistry and Technology

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High resolution magic angle spinning (HRMAS) is utilized here to characterize the structure of solid lignin from Quercus alba (white oak) wood that has been biodegraded by the brown rot (BR) fungus Laetiporus sulphureus. The ground wood sample is swelled in deuterated solvent, allowing an enhanced molecular motion that is required for obtaining 2D HRMAS spectra. This technique provides for direct, noninvasive analysis of solid biodegraded lignin. Emphasis is placed on the characterization of the lignin side chains in an effort to elucidate the types of linkages connecting the various monomers. The HRMAS spectra obtained provide evidence for the presence of structures in this biodegraded lignin that have been commonly found in chemically extracted lignins and model compounds. This information supports the existence of several of the six major types of lignin linkages (β-O-4, β-5, β-1, 5-5, 4-O-5, and β-β) as well as three other structures: dibenzodioxocin, isochroman, and spirodienone.

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Structural Studies of Lignin Isolation Procedures by¹³C NMR

Cited by 79 publications

References 9 publications

Tillage impacts on the fractions and compositions of soil organic carbon

Tillage impacts on the fractions and compositions of soil organic carbon

Differences between Lignin in Unprocessed Wood, Milled Wood, Mutant Wood, and Extracted Lignin Detected by ¹³C Solid-State NMR

NMR Structural Characterization ofQuercus alba(White Oak) Degraded by the Brown Rot Fungus,Laetiporus sulphureus

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Structural Studies of Lignin Isolation Procedures by13C NMR

Cited by 79 publications

References 9 publications

Tillage impacts on the fractions and compositions of soil organic carbon

Tillage impacts on the fractions and compositions of soil organic carbon

Differences between Lignin in Unprocessed Wood, Milled Wood, Mutant Wood, and Extracted Lignin Detected by 13C Solid-State NMR

NMR Structural Characterization ofQuercus alba(White Oak) Degraded by the Brown Rot Fungus,Laetiporus sulphureus

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Product

Resources

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Structural Studies of Lignin Isolation Procedures by¹³C NMR

Differences between Lignin in Unprocessed Wood, Milled Wood, Mutant Wood, and Extracted Lignin Detected by ¹³C Solid-State NMR