Isolation Of Lignin Research Articles

Structural variations of lignin macromolecule from different growth years of Triploid of Populus tomentosa Carr.

To better understand the variations of structural characteristics of lignin macromolecules during different growth years of Triploid of Populus tomentosa Carr, a novel lignin isolation procedure based on double ball-milling and enzymatic hydrolysis (DEL) was proposed in this study. The morphological distributions of lignin in the plant cell wall of these poplar wood samples were monitored by Confocal Raman Microscopy (CRM). The ultrahigh yields (105.1%–111.2%) of DELs were significantly higher than those (24.4–31.8%) of corresponding cellulolytic enzyme lignins (CELs). DELs and CELs were elaborately characterized by HPAEC, GPC, 2D-HSQC NMR and 31P NMR techniques, and NMR results showed that DEL samples possess similar structural features as compared to CEL counterparts except for the decreased S/G ratio and p-hydroxybenzoate (PB) as well as increased p-hydroxyphenyl units (H). There are no obvious differences in the structural characteristics except for high contents of PB and H units in DEL-1, as well as high S/G ratio and β-O-4′ linkages in DEL-5. It is believed that the DEL proposed in the present study can be used for characterizing the entire structural features of lignin macromolecules in the plant cell wall of different kinds of lignocellulosic biomass.

Isolation and Characterization of Gramineae and Fabaceae Soda Lignins.

Some agricultural residues such as wheat or barley straw, as well as certain fast-growing plants like Leucaena leucocephala and Chamaecytisus proliferus, could be used as raw materials for the paper industry as an alternative to traditional plants (eucalyptus, pine, etc.). In the present study, four types of lignin obtained from the spent liquors produced by the pulping processes using the abovementioned feedstocks were isolated and characterized. Lignin samples were acquired through an acid precipitation from these spent liquors. The characterization of the precipitated lignin samples were performed using a Fourier transform infrared spectroscopy (FT-IR) and both liquid- and solid-state nuclear magnetic resonance spectroscopy (NMR) to analyse the chemical structure, and thermogravimetric analysis (TGA) for determining the thermal properties. Additionally, chemical composition of lignin fractions was also measured. Even though they were of different botanical origin, all the studied samples except for wheat straw lignin had a similar chemical composition and thermal behaviour, and identical chemical structure. Wheat straw lignin showed a greater amount of Klason lignin and lower carbohydrate content. Furthermore, this lignin sample showed a higher thermal stability and significantly different cross-peak patterns in the 2D-NMR experiments. The molecular structures corresponding to p-coumarate (PCA), ferulate (FA) and cinnamyl aldehyde end-groups (J) were only detected in wheat isolated lignin.

Characterization of the precipitated lignin from Japanese beech as treated by semi-flow 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.

Lignin Isolation from Coconut Coir with Variation of Time and Concentration of NaOH in Process of Alkaline Delignification

Lignin Isolation from Coconut Coir with Variation of Time and Concentration of NaOH in Process of Alkaline Delignification

PEMBUATAN SURFAKTAN SODIUM LIGNO SULFONAT DARI AMPAS TEBU

Bagasse is one of the agricultural waste which is quite high at 19.7%. This research aims to assess the possibility of the use of bagasse as raw material for the manufacture of surfactants. Variable research is the concentration of NaHSO3 and long reaction time. The research was conducted using a three-neck flask reactor operated at 105 0 C and pH 4. Bagasse was pulverized to 120 mesh size, extracted with methanol for isolation of lignin. Furthermore, lignin reacted with NaHSO3 in a threeneck flask at 105 0C and pH 4. The results showed that the greater the concentration NaHSO3 and the longer the reaction time, the amount of lignosulfonates produced even greater. The optimum condition was obtained at a concentration of 30% NaHSO3 and the long reaction time of 60 minutes to produce the amount of lignosulfonate 17209.238 ppm or a yield of 20.717%.

Выделение, изучение и применение органосольвентных лигнинов (обзор)

Выделение, изучение и применение органосольвентных лигнинов (обзор)

Effect of hydrothermal pretreatment on the structural changes of alkaline ethanol lignin from wheat straw.

Due to the enormous abundance of lignin and its unique aromatic nature, lignin has great potential for the production of industrially useful fuels, chemicals, and materials. However, the rigid and compact structure of the plant cell walls significantly blocks the separation of lignin. In this study, wheat straw was hydrothermally pretreated at different temperatures (120–200 °C) followed by post-treatment with 70% ethanol containing 1% NaOH to improve the isolation of lignin. Results demonstrated that the content of associated carbohydrates of the lignin fractions was gradually reduced with the increment of the hydrothermal severity. The structure of the lignins changed regularly with the increase of the pretreatment temperature from 120 to 200 °C. In particular, the contents of β-O-4′, β-β′, β-5′ linkages and aliphatic OH in the lignins showed a tendency of decrease, while the content of phenolic OH and thermal stability of the lignin fractions increased steadily as the increment of the pretreatment temperature.

Structural elucidation of Eucalyptus lignin and its dynamic changes in the cell walls during an integrated process of ionic liquids and successive alkali treatments

An integrated process based on ionic liquids ([Bmim]Cl and [Bmim]OAc) pretreatment and successive alkali post-treatments (0.5, 2.0, and 4.0% NaOH at 90°C for 2h) was performed to isolate lignins from Eucalyptus. The structural features and spatial distribution of lignin in the Eucalyptus cell wall were investigated thoroughly. Results revealed that the ionic liquids pretreatment promoted the isolation of alkaline lignin from the pretreated samples without obvious structural changes. Additionally, the integrated process resulted in syringyl-rich lignin macromolecules with more β-O-4′ linkages and less phenolic hydroxyl groups. Confocal Raman microscopy analysis showed that the dissolution behavior of lignin was varied in the morphologically distinct regions during the successive alkali treatments, and lignin dissolved was mainly stemmed from the secondary wall regions. These results provided some useful information for understanding the mechanisms of delignification during the integrated process and enhancing the potential utilizations of lignin in future biorefineries.

Characterization of Lignin Isolated from Wheat Leaf Based on LiCl/DMSO Dissolution and Regeneration

The isolation of lignin is of great importance to understand its structural characteristics. A lithium chloride/dimethyl sulfoxide (LiCl/DMSO) solvent system has been developed for the dissolution of lignocellulose and for the isolation of lignin for this purpose. In this work, ball-milled wheat leaf (sheath included) was dissolved in the LiCl/DMSO solvent system and then regenerated in water. Two lignin preparations, cellulolytic enzyme lignin from the ball-milled leaf (CEL) and from the regenerated leaf (RCEL), were obtained through a cellulolytic enzyme lignin procedure. The RCEL and CEL were comparatively investigated by the use of wet chemistry and spectroscopic methods. The results indicate that the effects of ball milling and regeneration on the aromatic structure and β-O-4’ linkages of lignin were not significant. The RCEL had a higher isolation yield and purity, but a similar structure with the corresponding CEL. The RCEL can be used for structural analysis.

Isolation and Characterization of Organosolv and Alkaline Lignins from Hardwood and Softwood Biomass

Isolation of lignins from hardwood and softwood biomass samples, containing 26.1% and 28.1% lignin, respectively, has been performed with the use of alkaline and organosolv pretreatment methods. The effect of catalyst loading, ethanol content, particle size, and pretreatment time on the yields and properties of the isolated lignins were investigated. Alkaline lignins had higher carbohydrate content—up to 30%—and exhibited higher molecular weights in the range of 3000 Da, with a maximum phenolic hydroxyl content of 1 mmol g–1 for birch and 2 mmol g–1 for spruce. Organosolv lignins, on the other hand, showed high purity—93% or higher—despite the more extensive biomass dissolution into the pretreatment medium; they also exhibited a lower range of molecular weights between 600 and 1600 Da depending on the source and pretreatment conditions. Due to the lower molecular weight, phenolic hydroxyl content was also increased, reaching as high as 4 mmol g–1 with a simultaneous decrease in aliphatic hydroxyl content ...

Solubility of Organosolv Lignin in γ-Valerolactone/Water Binary Mixtures.

The solubility of lignin in a mixture of γ‐valerolactone (GVL) and water at different weight ratios was measured using the Hildebrand solubility parameters. Based on the molecular structure of lignin, its solubility parameter (δ‐value) was calculated as 25.5 MPa1/2. The δ‐value for aqueous GVL solvent increased from 23.1 MPa1/2 for pure GVL to 45.6 MPa1/2 for pure water. Therefore, the lignin solubility was predicted to increase with increasing GVL concentration in the aqueous mixture up to approximately 92–96 wt % of GVL. A ternary diagram describing the phase behavior of water–GVL–lignin mixtures at room temperature was constructed based on the experimental results. The three‐component system exhibited a complex behavior with a liquid–liquid and solid–liquid–liquid phase split. The efficiency of the selected fractionation trials in a previous work was validated using the ternary solubility diagram. A promising recovery pathway and lignin isolation method were deduced from the results of this work.

Isolation of lignin by organosolv process from different varieties of rice husk: Understanding their physical and chemical properties

The aim of this work was to study the difference in properties of lignins, those (organosolv lignins (ORGLs, 12±3% yield and 93±5% mass balance) were isolated from diverse rice husk (RH) substrates using organosolv procedure (water:ethanol, H2SO4) carried out at 180°C for 1h. To identify the possible alterations in lignin structures several bulk and molecular level advanced characterization tools were employed. Even though lignins were extracted using common isolation procedure from three varieties of similar species of RH; from XRD, GPC, and elemental analysis it was found that those have comparable properties on bulk level. But molecular level analysis conducted using UV–vis, ATR, 1D/2D HSQC NMR techniques could help disclose that isolated lignins have varying concentrations of G, H, S and T substructures. Additionally, the double bond equivalence of 4.4–4.7 reveals that few of the aromatic rings are devoid of substituent.

The utilization of soybean straw III: Isolation and characterization of lignin from soybean straw

To improve the yield of cellulolytic enzyme lignin (CEL) and to minimize the structural changes induced by isolation, the dissolution-regeneration of ball-milled soybean stem in a lithium chloride (LiCl)/dimethyl sulfoxide (DMSO) solvent was applied prior to enzymatic hydrolysis. The regenerated stem was enzymatically hydrolyzed for 72 h to remove the carbohydrates and then extracted with 1, 4-dioxane to obtain the cellulolytic enzyme lignin (named as DR-CEL). As expected, the yield of DR-CEL was much higher than that of CEL. With 2 h of ball-milling, the yield of DR-CEL was 40.1% (based on the total lignin in the raw stem). As the ball-milling time increased to 4 h, the yield of DR-CEL improved up to 82.4%, which was much higher than that of CEL with a yield of 26.0%. All the isolated lignin preparations were characterized using FT-IR, 1H NMR and 1H-13C HSQC NMR. The results showed that the main structural characteristics of these two kinds of lignin (CEL & DR-CEL) were similar, except for a slightly higher amount of carbohydrates in DR-CEL. As a result, the combination of the dissolution–regeneration and enzyme hydrolysis of ball-milled sample has a great potential in isolating lignin with higher yield and minimal structural changes.

ChemInform Abstract: Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

AbstractReview: 427 refs.

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis.

Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine‐tuning of multiple “upstream” (i.e., lignin bioengineering, lignin isolation and “early‐stage catalytic conversion of lignin”) and “downstream” (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a “beginning‐to‐end” analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

Complete Dissolution of Ball-Milled Masson Pine Using an Aqueous Sodium Hydroxide Solvent

An inorganic sodium hydroxide aqueous solution was developed for the dissolution of ball-milled softwood. Extractive-free Masson pine powder was prepared from the wood meal by planetary ball milling for various lengths of time. The effects of ball milling on the dissolution and regeneration of Masson pine powder were investigated. After 4 h of ball milling, the wood powder was completely dissolved in 6 wt% NaOH aqueous solution under vigorous magnetic stirring for 10 to 20 min at room temperature. The alkaline nitrobenzene oxidation products yield of 4 h ball-milled wood was very close to that of coarse wood meal without ball milling. Regeneration of the lignin fraction was easier than cellulose during the acid neutralization process, and the dialysis regeneration yield of total biomass was 91.1%. Therefore, the complete dissolution of the Masson pine in sodium hydroxide solution is of great potential for enhancing lignin isolation with a very little structural change.

Isolation and Thermal Characterization of Softwood-Derived Lignin with Thermal Flow Properties

A potential alternative biorefinery platform, in which high quality lignin is the main product of the process, is demonstrated. The polyethylene glycol (PEG)-modified softwood lignin (glycol lignin, GL) was isolated from Japanese cedar by acid-catalyzed PEG solvolysis, where liquid PEG with varying polymer chain length was used as the solvolysis reagent with a small amount of acid catalyst. The isolated glycol lignin had the weight-average molecular weight of 4000–7000 and exhibited a viscous thermal flow property, which is impossible for industrial softwood lignin without further processing steps. Thermal analyses, such as thermomechanical analysis (TMA) and capillary flow tester rheometer (CFT), proved to be sensitive techniques for determination of thermal flow behavior. The lignin yield and solid residue (mostly cellulosic residue), respectively, of 28%–31% and 36%–38% (dry wood basis) were obtained from PEG200 solvolysis with 0.5%–0.7% acid catalyst. The results indicated the effectiveness of the one...

Isolation and Physicochemical Characterization of Lignin from <i>Chromolaena Odorata</i> and <i>Tithonia Diversifolia</i>

This study dealt with isolation of lignin from soft woods namely; Chromolaena odorata (Siam Weed) and Tithonia diversifolia (Mexican Sunflower) using alkali pretreatment method. The raw samples were characterized by some physico-chemical parameters before extraction. Chromolaena odorata gave higher lignin yield and lesser ash content of 15.12 % and 4.22 % respectively compared to Tithonia diversifolia with 7.40 % and 9.56 % respectively. The isolated lignins were characterized by some physico-chemical parameters and spectroscopy methods like Futran Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). Lignin from Chromolaena odorata was found to be more pure than the one from Tithonia diversifolia as evident from the values of ash content (4.22%) and klason lignin (33.65 %) for Chromolaena odorata while ash content (9.56 %) and klason lignin (21.96 %) were obtained from Tithonia diversifolia. The FT-IR spectra of both lignins revealed the presence of syringyl and guaiacyl units.Keywords: Chromolaena odorata, Tithonia diversifolia, Lignin, FT-IR, Physico chemical parameters

PEMBUATAN PEREKAT LIGNIN RESORSINOL FORMALDEHID DARI NATRIUM LIGNOSULFONAT TANDAN KOSONG KELAPA SAWIT

Oil palm empty fruit bunchesn are waste from palm oil mill utilization is still limited. Lignin utilization of oil palm empty fruit bunhes made of natural adhesive manufacture. Making adhesive is carried out in several stages namely the manufacture of powder oil palm empty fruit bunches free extractives, lignin isolation, the manufacture of sodium lignosulfonate, sodium purification lignosulfonate and the manufacture of adhesive. Making the lignin resorcinol formaldehide adhesive is done by differences sodium lignosulfonate : resorcinol : formaldehyde mole ratio are ratio 1:1:1, ratio 1:1:2 and ratio 1:1:3. The results obtained from testing the appearance of the adhesive has a blackish brown color. pH of each ratio is ratio 1:1:1 11,2, ratio 1:1:2 11,4 and ratio 1:1:3 12,0. Adhesive densities are ration 1:1:1 1,2857, ratio 1:1:2 1,2119, and ratio 1:1:3 1,3097. Viscosities are ratio 1:1:1 108,83 cps, ratio 1:1:2 94,31 cps and ratio 1:1:3 129,92 cps. The rest of the evaporation are ratio 1:1:1 50,77%, ratio 1:1:2 42,35% and ratio 1:1:3 41,01%. Test results compared with standard phenol formaldehyde which is SNI 06-4567-1998 liquid phenol formaldehyde and result ratio 1:1:3 the best of another ratio .

Isolation and characterization of lignin from okra (Abelmoschus esculentus) fibre and stick

The okra (Abelmoschus esculentus) plant consists of bast fiber and core (stick). The bast fibre of okra plant was characterized with high ?-cellulose (56.7%) and low lignin (12.6%) and stick withlow ?-cellulose (34.3%) and high lignin (25.2%) content. Lignin was isolated from the fiber and stick by acidolytic dioxane method and characterized for elemental analysis, methoxyl analysis and FTIR and 1H-NMR spectroscopy. The C9 formulas for okra stick and fibre lignin were C9H9.61O4.63(OCH3)1.24 and C9H8.61O4.66(OCH3)1.49, respectively. Both of the lignins were of the guaiacyl-syringyl type. The bands of FT-IR spectrum at 1327 cm-1, 1122 cm-1 and 837 cm-1 associated with syringyl unit was higher in okra fibre lignin than in the okra stick lignin. The structural analysis revealed that the average numbers of proton of ?-O-4 (H? & H?) per C9 unit in okra stick and fibre lignin were 1.53 and 1.20, respectively. The ?-O-4 units in these lignins had predominately erythro stereochemistry type.Bangladesh J. Sci. Ind. Res. 50(4), 257-262, 2015