Characterization of autohydrolysis aspen (P. tremuloides) lignins. Part 4. Residual autohydrolysis lignin

Lignocellulosic residue remaining after autohydrolysis of extractive-free aspen wood meal at 195 °C for periods of time varying from 5 to 120 min followed by extraction with 90% dioxane was subjected to enzymatic hydrolysis to obtain residual lignin. Infrared studies indicated that in the early stages of autohydrolysis residual lignin resembles protolignin, but as autohydrolysis proceeds it changes to resemble more and more the extracted lignin. Residual lignin was found to be higher in carbon but lower in hydrogen and oxygen than aspen milled wood lignin. The methoxyl content was also lower than the reference lignin. From alkaline nitrobenzene oxidation, residual lignin is seen to become more condensed with increasing autohydrolysis time. The insolubility of residual lignin is attributed to the existence of strong bonds between this lignin and carbohydrate.

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Characterization of autohydrolysis aspen (P. tremuloides) lignins. Part 2. Alkaline nitrobenzene oxidation studies of extracted autohydrolysis lignin

Canadian Journal of Chemistry ◽

10.1139/v79-420 ◽

1979 ◽

Vol 57 (19) ◽

pp. 2599-2602 ◽

Cited By ~ 24

Author(s):

Morris Wayman ◽

Miranda G. S. Chua

Keyword(s):

Molecular Weight ◽

Molar Ratio ◽

Low Molecular Weight ◽

Aspen Wood ◽

Milled Wood Lignin ◽

Wood Meal ◽

Nitrobenzene Oxidation ◽

Carbon Carbon Bonds ◽

Degree Of Condensation

Alkaline nitrobenzene oxidation of the lignins extracted from extractive-free aspen wood meal after autohydrolysis at 195 °C for periods varying from 5 min to 2 h indicated that these lignins were structurally more condensed in terms of an increase in new carbon–carbon bonds than aspen milled wood lignin. The degree of condensation generally increased with longer autohydrolysis times. It is postulated that condensation involved materials from both the carbohydrate and lignin components of the wood which were generated during the autohydrolysis. The molar ratio of syringaldehyde to vanillin of extracted lignin on oxidation was observed to decrease with increasing autohydrolysis time. It is suggested that syringyl units are preferentially extracted as low molecular weight material.

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Understanding the effects of different residual lignin fractions in acid-pretreated bamboo residues on its enzymatic digestibility

Biotechnology for Biofuels ◽

10.1186/s13068-021-01994-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Wenqian Lin ◽

Jinlai Yang ◽

Yayue Zheng ◽

Caoxing Huang ◽

Qiang Yong

Keyword(s):

Enzymatic Hydrolysis ◽

Negative Impact ◽

Dilute Acid Pretreatment ◽

Residual Lignin ◽

Dilute Acid ◽

Enzymatic Digestibility ◽

Acid Pretreatment ◽

Organic Reagents ◽

Milled Wood Lignin ◽

Affinity Constants

Abstract Background During the dilute acid pretreatment process, the resulting pseudo-lignin and lignin droplets deposited on the surface of lignocellulose and inhibit the enzymatic digestibility of cellulose in lignocellulose. However, how these lignins interact with cellulase enzymes and then affect enzymatic hydrolysis is still unknown. In this work, different fractions of surface lignin (SL) obtained from dilute acid-pretreated bamboo residues (DAP-BR) were extracted by various organic reagents and the residual lignin in extracted DAP-BR was obtained by the milled wood lignin (MWL) method. All of the lignin fractions obtained from DAP-BR were used to investigate the mechanism for interaction between lignin and cellulase using surface plasmon resonance (SPR) technology to understand how they affect enzymatic hydrolysis Results The results showed that removing surface lignin significantly decreased the yield for enzymatic hydrolysis DAP-BR from 36.5% to 18.6%. The addition of MWL samples to Avicel inhibited its enzymatic hydrolysis, while different SL samples showed slight increases in enzymatic digestibility. Due to the higher molecular weight and hydrophobicity of MWL samples versus SL samples, a stronger affinity for MWL (KD = 6.8–24.7 nM) was found versus that of SL (KD = 39.4–52.6 nM) by SPR analysis. The affinity constants of all tested lignins exhibited good correlations (r > 0.6) with the effects on enzymatic digestibility of extracted DAP-BR and Avicel. Conclusions This work revealed that the surface lignin on DAP-BR is necessary for maintaining enzyme digestibility levels, and its removal has a negative impact on substrate digestibility.

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Characterization of Residual Lignin Obtained by the Enzymatic Hydrolysis of Oil Palm Empty Fruit Bunch Pulps

BioResources ◽

10.15376/biores.12.1.183-194 ◽

2016 ◽

Vol 12 (1) ◽

Cited By ~ 2

Author(s):

Yin Ying H'ng ◽

Akiko Nakagawa-Izumi ◽

Cheu Peng Leh ◽

Atanu Kumar Das ◽

Hiroshi Ohi

Keyword(s):

Enzymatic Hydrolysis ◽

Oil Palm ◽

Empty Fruit Bunch ◽

Residual Lignin ◽

Hydrolysis Of

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THE ALKALINE NITROBENZENE OXIDATION OF ASPEN WOOD AND LIGNIN MODEL SUBSTANCES

Canadian Journal of Chemistry ◽

10.1139/v55-005 ◽

1955 ◽

Vol 33 (1) ◽

pp. 24-30 ◽

Cited By ~ 18

Author(s):

K. R. Kavanagh ◽

J. M. Pepper

Keyword(s):

Reaction Time ◽

Sodium Hydroxide ◽

Maximum Yield ◽

Aspen Wood ◽

Wood Meal ◽

Nitrobenzene Oxidation ◽

Subsequent Heating ◽

Lignin Model ◽

Model Substances

The yields of vanillin and syringaldehyde obtained by the alkaline nitrobenzene oxidation of aspen wood meal have been determined at various temperatures for various times. The maximum yield of each of these aldehydes, ca. 15 and 36% respectively, was obtained under the same conditions. Similar maximum yields result at 130 ± 5 °C. as at 170 ± 5 °C. if the reaction time is markedly increased. Treatment of the wood meal with sodium hydroxide at 160 °C. for two and one half hours prior to the addition of nitrobenzene and subsequent heating under the same conditions decreases, by over 30%, the yields of aldehydes. Samples of 3,4,5-trimethoxybenzaldehyde, β-D-glucovanillin, and β-D-glucosyringaldehyde were oxidized by alkaline nitrobenzene at 160 °C. for two and one half hours and yields of the corresponding phenolic aldehydes of 10.7, 69.6, and 71.9% respectively were obtained. These results are discussed with respect to the chemistry of aspen lignin.

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Characterization of Residual Lignin after SO2-Catalyzed Steam Explosion and Enzymatic Hydrolysis ofEucalyptus viminalisWood Chips

Journal of Agricultural and Food Chemistry ◽

10.1021/jf9810665 ◽

1999 ◽

Vol 47 (6) ◽

pp. 2295-2302 ◽

Cited By ~ 14

Author(s):

L. P. Ramos ◽

A. L. Mathias ◽

F. T. Silva ◽

A. R. Cotrim ◽

A. L. Ferraz ◽

...

Keyword(s):

Enzymatic Hydrolysis ◽

Steam Explosion ◽

Residual Lignin

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Characterization of autohydrolysis aspen (P. tremuloides) lignins. Part 1. Composition and molecular weight distribution of extracted autohydrolysis lignin

Canadian Journal of Chemistry ◽

10.1139/v79-187 ◽

1979 ◽

Vol 57 (10) ◽

pp. 1141-1149 ◽

Cited By ~ 112

Author(s):

Miranda G. S. Chua ◽

Morris Wayman

Keyword(s):

Molecular Weight ◽

Molecular Weight Distribution ◽

Weight Distribution ◽

Blocking Agent ◽

Low Molecular Weight ◽

Aspen Wood ◽

Milled Wood Lignin ◽

Carbonium Ions ◽

Distribution Studies

Extractive-free aspen wood meal was subjected to autohydrolysis at 195 °C for 5 min to 2 h, and the lignin extracted with 90% dioxane. Extracted autohydrolysis lignin was found to be higher in carbon but lower in hydrogen and oxygen content than aspen milled wood lignin. The methoxyl content was also lower than the reference lignin. These differences have been attributed to condensation and incorporation into the lignin of non-lignin components. A lignin extractability curve with a maximum delignification at autohydrolysis time of 30–40 min was found. From molecular weight distribution studies the ratio of high molecular weight to low molecular weight materials varied for the different extracted lignins and reached a maximum at autohydrolysis time of 40 min. A mechanism of depolymerization/repolymerization of the lignin via carbonium ions has been proposed. p-Hydroxybenzoic acid is postulated as contributing to the extractability of aspen lignin by acting as a blocking agent.

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Characterization of the precipitated lignin from Japanese beech as treated by semi-flow hot-compressed water

Holzforschung ◽

10.1515/hf-2016-0139 ◽

2017 ◽

Vol 71 (4) ◽

pp. 285-290 ◽

Cited By ~ 3

Author(s):

Masatsugu Takada ◽

Eiji Minami ◽

Kazuchika Yamauchi ◽

Haruo Kawamoto ◽

Shiro Saka

Keyword(s):

Secondary Wall ◽

Fagus Crenata ◽

Spectroscopic Methods ◽

Ambient Conditions ◽

Flow Process ◽

Japanese Beech ◽

Milled Wood Lignin ◽

Nitrobenzene Oxidation ◽

Hot Compressed Water

Abstract Japanese beech (Fagus crenata) was decomposed by a semi-flow process in hot-compressed water (HCW) at 150~230°C/10 MPa for 25 min. Mainly hemicelluloses and partly the lignin moiety of the wood was affected and liquefied in water. A part of the liquefied products can be precipitated after 12 h standing at ambient conditions. The precipitates are composed of around 90% of lignin, which was quantified and characterized by various chemical and spectroscopic methods in comparison of milled wood lignin (MWL), which is considered to be a representative compound for the native lignin in wood. The yield of the precipitated lignin (Lprecip) is higher than that of MWL and its syringyl content is also higher as demonstrated by alkaline nitrobenzene oxidation (NBO) giving rise to higher syringaldehyde/vanillin (SA/VA) ratios. Its OHphen group content was also high. The interpretation is that Lprecip is mainly from the secondary wall, and accordingly, the presented semi-flow HCW treatment offers the possibility for an efficient lignin isolation.

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