Isolation Of Lignin Research Articles

Flow-through solvolysis enables production of native-like lignin from biomass

Flow-through solvolysis offers an opportunity to limit lignin condensation reactions that prevent isolation of native lignin in biomass processing, thus allowing for the study of intrinsic lignin properties and steady-state lignin depolymerization.

Bio-based Products from Lignocellulosic Waste Biomass

This review presents data on the chemical composition of harvest residues and food <br /> industry by-products as widely abundant representatives of lignocellulosic waste biomass. Pretreatment methods, with special emphasis on biological methods, are presented <br /> as an important step in utilization of lignocellulosic waste biomass for the production of <br /> sustainable biofuels and high-value chemicals. Special attention was paid to the methods <br /> of lignin isolation and its possible utilization within lignocellulosic biorefinery. The objectives of circular bioeconomy and the main aspects of lignocellulosic biorefinery are <br /> highlighted. Finally, current data on industrial, pilot, and research and development <br /> plants used in Europe for the production of a variety of bio-based products from different <br /> feedstocks are presented.

Isolasi Lignin dari Serbuk Grajen Kayu Jati (Tectona Grandis) dengan Metode Klasson

Isolation of lignin from Jepara teak furniture waste is an effort to utilize this waste and to overcome environmental pollution. Lignin was isolated by extraction from the sawdust of furniture waste, hydrolyzed and identified by Fourier Transport Infra-Red (FTIR). Isolation was carried out with a sample weight of 10 grams, a time of 2 hours and a temperature of 110oC and variations in the concentration of NaOH. The lignin yield of 0,106% (1,06 g) was obtained at a concentration of 12%-w NaOH, time of 2 hours and a temperature of 110oC. The guacil functional group as the dominated element of the lignin compounds was identified by FTIR spectra results at the absorption wavelength of 1269,6 cm-1.

Pyridinium protic ionic liquids: Effective solvents for delignification of wheat straw

Lignocellulosic biomass covers a vast area of the globe and contains many valuable components that can be envisaged for numerous renewable products. The valorization of these components is hindered by its cumbersome isolation due to the recalcitrant nature of lignocellulosic biomass. Acidic ionic liquids (AILs) have emerged in this field as effective pretreatment solvents. The unique property of disrupting lignin-cellulose-hemicellulose bonds and dissolving lignin makes these ILs significant for the separation of lignin and cellulosic constituents. In this study three protic ionic liquids based on pyridinium cation and hydrogen sulfate anion (HSO4−) have been synthesized; [PyH][HSO4] (IL1), [PyH][HSO4. (H2SO4)] (IL2), and [PyH][HSO4 . (H2SO4)3] (IL3) and utilized for the isolation of lignin from wheat straw. The synthesized ILs were characterized by NMR and FTIR analyses. The lignin yield was optimized with respect to reaction temperature, time, biomass loading, and type of IL. The lignin removal efficacy of the ionic liquid with highest ratio of acid [PyH][HSO4.(H2SO4)3] (IL3) is indicated by high delignification (79%) and lignin recovery (77%) under mild conditions (60 °C, 2 h). The cellulose rich material (CRM) and isolated lignin were characterized by FTIR, SEM, TGA, GPC, and HSQC NMR to assess their structure, molecular weight and stability. The cellulosic part was further hydrolyzed enzymatically to evaluate the capability of the recovered pulp to generate glucose. An appreciable yield of reducing sugars (85%) substantiates high lignin removal.

2G waste lignin to fuel and high value-added chemicals: Approaches, challenges and future outlook for sustainable development

Lignin is produced as a byproduct in cellulosic biorefinery as well in pulp and paper industries and has the potential for the synthesis of a variety of phenolics chemicals, biodegradable polymers, and high value-added chemicals surrogate to conventional petro-based fuels. Therefore, in this critical review, we emphasize the possible scenario for lignin isolation, transformation into value addition chemicals/materials for the economic viability of current biorefineries. Additionally, this review covers the chemical structure of lignocellulosic biomass/lignin, worldwide availability of lignin and describe various thermochemical (homogeneous/heterogeneous base/acid-catalyzed depolymerization, oxidative, hydrogenolysis etc.) and biotechnological developments for the production of bio-based low molecular weight phenolics, i.e. polyhydroxyalkanoates, vanillin, adipic acid, lipids etc. Besides, some functional chemicals applications, lignin-formaldehyde ion exchange resin, electrochemical and production of few targeted chemicals are also elaborated. Finally, we examine the challenges, opportunities and prospects way forward related to lignin valorization.

Optimization of lignin extraction from alkaline treated mango seed husk by high shear homogenization-assisted organosolv process using response surface methodology

Lignin valorisation into materials such as resins is essential to increase the value obtained from biomass. However, biomass recalcitrance limits the selective isolation of lignin for economic gains. This study developed a new process for fractionating alkaline treated mango seed husk into high purity lignin and cellulose-rich pulp, using high shear homogenization-organosolv (HSHO) process. The HSHO process conditions (ethanol concentration (50–70%), temperature (130–150 °C) and homogenizing time (10–20 min)) were optimized using response surface methodology to maximize the solubilised lignin with high purity while obtaining a fibrillated cellulose-rich pulp. Optimum process conditions of 60% ethanol, 148.41 °C, and 15 min homogenization, yielded 70.23% lignin of 96.18% purity, higher than those of the non-assisted process (68.58% and 94.74%, respectively). Nuclear magnetic resonance spectroscopy showed syringyl and guaiacyl lignin units with a molecular weight of 3247 g/mol and thermal degradation temperature of 298 °C. Sulphur and nitrogen contents in the resulting lignin were lower than 0.15%. Fibrillated cellulose pulp with diameters of <1–10 μm were obtained. This study has established the proficiency of an HSHO process for biomass fractionation and more so, for the extraction of lignin with >90% purity suitable for varied applications.

Effect of amphiphilic lignin derivatives (A-LD) surfactant addition on the fermentation process of sorghum bagasse kraft pulp for bioethanol production

This research was intended to study the effect of Amphiphilic Lignin Derivatives (A-LD) surfactant addition on the bioethanol production by using simultaneous saccharification and fermentation (SSF) system. A-LD synthesis was obtained from single-step lignin isolation from black liquor as a by-product of the Acacia mangium kraft process. This synthesis was carried out by reacting single-step lignin isolation with the polyethylene glycoldiglycidylether (PEDGE), which was heated at 60 °C for one h. SSF was performed by using Saccharomyces cerevisiae InaCC Y93, cellulase enzyme of 50 FPU/g, yeast inoculum in 10% and 20%, and a 15 mg/mL A-LD added into 5.37 g (wet weight) of sweet sorghum bagasse (SSB) kraft pulp. The concentration of reducing sugar and the ethanol contents were analyzed every 24 h for 72 h and also at 89 h. The ethanol concentration, ethanol yield, and the highest percentage of theoretical ethanol yield were 4.91 ± 0.10 g/L, 0.06 ± 0.001 g/g, and 11.29 ± 0.22%, respectively. They were obtained by 20% of yeast inoculum for 24 h fermentation on the SSF system and the addition of A-LD surfactant. The addition of A-LD on the SSF process increased ethanol production and shortened the fermentation time.

Techno-economic analysis of different integrated biorefinery scenarios using lignocellulosic waste streams as source for phenolic alcohols production

The whole process of lignin extraction from a lignocellulosic waste streams (almond shell) by sulfur-free methods and its depolymerization by base catalyzed or solvolysis reactions have been addressed in this work. In addition, the influence of avoiding the lignin isolation stage prior to its depolymerization reaction has been studied based on the final product yields (phenolic monomers compounds, such as catechol derivatives), energy requirements and production costs. As summary, four different scenarios were approached using experimental data values from previous works and compared by the help of a simulation software (AspenTech®). The direct lignin depolymerization from black liquors equalized the phenolic monomer yields of the precipitated lignin depolymerization for the organosolv process (0.08 wt%), and increased in the soda process (0.05 wt% against 0.03 wt%). However, the bigger volume to be treated in the depolymerization reaction and downstream stages significantly increased the production costs (chemicals consumptions, energetic duties and waste stream disposal), as well as the investment cost. Regarding the depolymerization from the precipitated lignin, despite the loss of lignin during the isolation stage, the reduction of the volume to be treated led to hugely reduce the production costs and the environmental impact. Among these last two mentioned scenarios, the organosolv process presented better indicators. Even though the lignin extraction yield was poorer for the organosolv process, the depolymerization performance was improved in such level, that the most desirable product (phenolic oil) was obtained in higher amount.

Lignin isolation from black liquor from oil palm empty fruit bunch using acid

This study aimed to obtain the characteristics of lignin isolated from oil palm empty fruit bunch by using HCl. Treatments were conducted using HCl at concentrations of 10%, 20%, 30% and 40% (v/v). Increasing HCl concentrations reduced yields but increased equivalent lignin weights and methoxyl contents. Results of functional group testing via Fourier transform infrared spectroscopy showed no change in the structure of functional groups at all HCl concentrations employed. Amongst the acid concentrations employed in this work, 20% HCl produced the maximum yield (15.61%). Increases in HCl concentration could increase methoxyl contents. In this study, average methoxyl contents were in in the range of 12.4–44.95%. The equivalent weight produced in this study ranged from 200% to 250%. Scanning electron microscopy–energy-dispersive X-ray results further showed that the dominant elements were carbon, oxygen, aluminium and iron. In addition, Chromatograms and identification of lignin compounds isolated using 40% HCl were presented.

Acidic deep eutectic solvent assisted isolation of lignin containing nanocellulose from thermomechanical pulp

Nanocellulose is a promising material but its isolation generally requires unrecyclable hazardous chemicals and high energy consumption and its overall yield is low due to the use of high purity cellulose as precursor. In order to overcome these shortcomings, in this study, thermomechanical pulp (TMP) was investigated as a precursor for isolating lignin containing nanocellulose (LNC) using an environmentally friendly acidic deep eutectic solvent (DES) pre-treatment. Flat “ribbon” like LNCs (around 7.1 nm wide, 3.7 nm thick) with uniformly distributed lignin nanoparticles of 20−50 nm in diameter were successfully obtained at 57 % yield under optimum pre-treatment conditions (90 °C, 6 h, 1:1 oxalic acid dihydrate to choline chloride ratio). The LNCs exhibit cellulose Iβ structure, high lignin content (32.6 %), and high thermal stability (Tmax of 358 °C). In general, green acidic DES pre-treatment has shown high efficiency in converting high lignin content biomass into value-added LNC, which benefits both lignocellulose utilization and environmental protection.

Nontargeted Analysis Strategy for the Identification of Phenolic Compounds in Complex Technical Lignin Samples.

Lignin is the second most abundant biopolymer in nature and a promising renewable resource for aromatic chemicals. For the understanding of different lignin isolation and conversion processes, the identification of phenolic compounds is of importance. However, given the vast number of possible chemical transformations, the prediction of produced phenolic structures is challenging and a nontargeted analysis method is therefore needed. In this study, a nontargeted analysis method has been developed for the identification of phenolic compounds by using an ultrahigh‐performance supercritical fluid chromatography–high‐resolution multiple stage tandem mass spectrometry method, combined with a Kendrick mass defect‐based classification model. The method is applied to a Lignoboost Kraft lignin (LKL), a sodium lignosulfonate lignin (SLS), and a depolymerized Kraft lignin (DKL) sample. In total, 260 tentative phenolic compounds are identified in the LKL sample, 50 in the SLS sample, and 77 in the DKL sample.

Structural changes in lignin of thermally treated eucalyptus wood

Changes in the lignin structure of eight eucalypt species (E. botryoides, E. globulus, E. grandis, E. maculata, E. propinqua, E. rudis, E. saligna, and E. viminalis) upon mild thermal treatment, where the temperature was gradually raised from 160 to 230 °C over 3 h, were studied by solid-state carbon nuclear magnetic resonance (13C NMR) and after lignin isolation from the wood by acidolysis employing liquid-state 1D and 2D NMR techniques. The molecular weight of the isolated lignins was assessed by size exclusion chromatography (SEC) and their composition by analytic pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS). The thermal treatment induced in lignin partial demethylation (up to ca. 30% from total) and a remarkable reduction in β-O-4 structures (up to ca. 60%), in an extent depending on the ratio of syringyl and guaiacyl units of the specific lignins. The lignin molecular weight reduced only ca. 25% under the thermal treatment due to the likely occurrence of condensation reactions by homolytic and heterolytic mechanisms. The noticeable increase in phenylcoumaran (β-5) and pinoresinol/syringaresinol (β-β) structures in lignin after thermal treatment was tentatively explained by their relative thermal resistance and by newly formed structures as the result of radical coupling reactions occurred during homolytic dissociation of the β-O-4 linkages. Lignins in thermally treated wood contained more than twice phenolic hydroxyls and more aliphatic carboxyl groups than lignins in untreated wood.

Biovalorization of Lignin

Lignocellulosic biomass comprises three components – cellulose, hemicellulose and lignin. Biorefining is defined as the separation, isolation and conversion of cellulose, hemicellulose and lignin from lignocellulosic biomass into fuels, chemicals, materials and energy. While a number of processes have been developed over the years to produce valuable products from cellulose and hemicellulose, processes utilizing lignin have been few and far between, largely owing to the severe recalcitrance of lignin. Our inability to utilize lignin is a lost opportunity for the green economy. Lignin is abundant and can provide a myriad of chemicals that could be used as building blocks for life-saving pharmaceuticals or even as flavours and food ingredients. The development of greener conversion platforms that can efficiently convert lignin into valuable products is highly desired. This paper summarizes recent progress made towards the development of a family of biocatalytic processes that convert lignin to pharmaceutical building blocks, flavouring agents and drug delivery platforms. Biocatalytic processes are greener, emit lesser carbon dioxide and are more energy efficient than other alternatives. The first family of biocatalysts selectively degrades lignin to its monoaromatic constituents and the second family of biocatalysts then modifies the monoaromatic constituents to desired target molecules. In particular, this paper describes the novel use of functional metagenomics and whole-cell biosensors for the discovery of 147 new biocatalysts that convert lignin into vanillin and syringaldehyde, and the identification of a novel transaminase that catalyzes the asymmetric synthesis of chiral amines from vanillin, syringaldehyde and 12 other monoaromatic aldehyde and ketone degradation products of lignin. Recent progress on the assembly of a metabolic pathway for the biosynthesis of the spice molecule capsaicin from vanillylamine, and the integration of the entire pathway that valorizes lignin to capsaicin into the metabolic network of E. coli has also been discussed. This work will eventually lead to the development of consolidated bioprocesses that convert lignin into value-added chemicals.

Isolation and Characterisation of Cellulose Nanofibre and Lignin from Oil Palm Empty Fruit Bunches.

A study on isolation and characterisation of cellulose nanofibre (CNF) and lignin was conducted to expand the application of CNF and lignin from oil palm biomass. CNF was extracted by steam explosion and the by-product was precipitated to obtain lignin by using the soda-pulping method. The concentrations of NaOH used for CNF by-product precipitation were 2%, 4%, and 6%. The morphology of CNF and lignin was characterised using scanning electron microscopy (SEM). The nanofibre of CNF with dimension between 50 nm and 100 nm was investigated using transmission electron microscopy (TEM). The functional group was observed using Fourier-transform infrared (FTIR) spectroscopy, showing that CNF had the structure of cellulose-I. In addition, the chemical structures of isolated and commercial lignin were analysed using 1H-NMR spectrometry. CNF had a 72% crystallinity index characterised by X-ray diffraction (XRD), while lignin showed an amorphous form. The characterisation of isolated lignin was compared with commercial lignin. The two lignins had similar particle size distribution from 1 to 100 μm. From UV-visible analysis, the lignin had aromatic rings/non-conjugated phenolic groups. The morphology of isolated lignin was rough and flaky. Commercial lignin was in powder form with near-spherical morphology. Thermogravimetric analysis (TGA) of CNF showed 30% of residue at 600 °C. The results showed a simple method to isolate CNF and lignin from oil palm empty fruit bunches.

Comparative evaluation of laccase mediated oxidized and unoxidized lignin of sugarcane bagasse for the synthesis of lignin-based formaldehyde resin

Pretreatment using dilute acid is one of the strategies employed in a lignocellulosic biorefinery. The current study deals with the isolation, characterization, and oxidation of lignin from the enzymatic residue of acid pre-treated sugarcane bagasse. The study also focused on evaluating the reactivity of Laccase mediated oxidized lignin with the non-oxidized one for the preparation of lignin-based formaldehyde (LF) resin. In the current study, 100 % phenolic lignin was utilized for the synthesis of LF resin. Three different approaches (Alkaline hydrolysis, mild acidolysis & organosolv) have been employed to evaluate the effect of isolation method on the physicochemical properties of lignin. The isolation method had a bearing on the properties of lignin and its reactivity towards formaldehyde for the synthesis of LF resin. Alkali and organosolv lignin were found as promising candidates for the preparation of LF resin. Oxidized lignin exhibited better reactivity than the non-oxidized one.

Pretreatment of lignocellulosic biomass at atmospheric conditions by using different organosolv liquors: a comparison of lignins

In order to strengthen the bio-based economy, it is necessary to produce value-added products by processing all fractions of the biomass, especially lignin. Isolation of lignin at atmospheric pressure and lower temperature will make it possible to recover lignin and use it for different purposes. In the present study, lignins were recovered from wood sawdust by applying six different organosolv treatments at atmospheric pressure. The lignins (ethanol organosolv lignin (EOL), alkaline glycerol organosolv lignin (AGOL), acetic acid organosolv lignin (AAOL), formic acid/acetic acid/water organosolv lignin (FAWOL 1 (40/40/20, v/v/v), FAWOL 2 (50/30/20, v/v/v), FAWOL 3 (30/50/20, v/v/v)) were compared in terms of yield, thermal properties, weight-average molecular weight, and fast pyrolysis properties. The effect of isolation method on lignin yield and structure was remarkable. Organosolv treatments at atmospheric conditions resulted in precipitation yields between 6.6% (ethanol organosolv) and 42% (alkaline glycerol organosolv). The lignin precipitated with the highest yield (AGOL) actually had the highest ash content (3.9%) and the lignin precipitated with the lowest yield (EOL) had the lowest ash content (1.2%). According to FTIR analysis, all lignins exhibited peaks at similar wavelengths but with different intensities. The weight-average molecular weight of lignins ranged between 1373 g/mol (AGOL) and 7400 g/mol (FAWOL 1). The polydispersity index of lignins ranged between 7.3 (FAWOL 1) and 2.5 (EOL and AAOL), where the lignins isolated from formic acid/acetic acid/water liquors showed higher polydispersity index compared to other lignins. Pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) revealed that pyrolysis product distribution was strongly affected from the isolation method. The most abundant phenolic compound, which was observed in all lignins, was 2-methoxy-4-methylphenol (4-methylguaiacol), which was followed by 2-methoxy-4- (2-propenyl) phenol (eugenol) and guaiacol, respectively. It has been observed that each lignin is a good candidate for a different end-use due to their own characteristics.

Isolation and Characterization of Lignin Using Coagulant Treatment in Black Liquid

Isolation and Characterization of Lignin Using Coagulant Treatment in Black Liquid

Valorization of Bark Using Ethanol–Water Organosolv Treatment: Isolation and Characterization of Crude Lignin

Bark serves multiple functions for a tree by combining protection and fluid transport. The tissue itself is composed of multiple types of material that includes typical cell wall structural polymer...

Fractionation by Sequential Antisolvent Precipitation of Grass, Softwood, and Hardwood Lignins Isolated Using Low-Cost Ionic Liquids and Water

In this study, fractionation by sequential anti-solvent precipitation was applied to ionoSolv lignins for the first time. Pretreatment with the aqueous low-cost protic ionic liquid N,N-dimethylbutylammonium hydrogen sulfate ([DMBA][HSO4], 80 wt% in water) was applied to Miscanthus (herbaceous), willow (hardwood) and pine (softwood) to extract lignin. Then, lignin was sequentially precipitated by addition of water as anti-solvent. Fractionation appeared to be controlled by molecular weight of lignin polymers. Fractions isolated with minimal water volumes were shown to have high molecular weight, polydispersity, thermal stability and Tg (178 °C). Later precipitates were more monodisperse, had high phenolic and total hydroxyl content, lower thermal stability and Tg (136 °C). Addition of 1 g of water per g of dry IL was able to precipitate up to 90 wt% of lignin. Fractional precipitation represents a novel lignin isolation technique that can be performed as part of the lignin recovery procedure enabling a hig...

Lignin Isolation from Black Liquor for Wastewater Quality Improvement and Bio-material Recovery

Spent pulping chemicals along with liberated lignin called black liquor are a major liquid waste stream from wood digestion process. For wastewater quality improvement, lignin residue could be isolated via various techniques. According to difference in chemical pulping process (kraft and soda), variations of organic and inorganic substance were suspended in waste stream. This research aims to investigate the effects of the cooking chemical on organic waste (lignin) in black liquor. Organic waste in black liquor was isolated as soda lignin (SL) from soda black liquor (SBL) and kraft lignin (KL) from kraft black liquor (KBL) by acidic precipitation. In addition, lignin model compound (LMC) was used to establish base case measurement. The elemental analysis revealed the similarity of C, H, and O content of samples in range of 32-33%, 3-4%, and 35-38%, respectively. FTIR results showed that structures of lignin, functional group and guaiacyl to syringyl ratio were vary depended on type of chemical pulping with β-O-4 as the primary composition of the samples. Moreover, Py-GC/MS technique was applied for analyzing the degradation products in order to corroborate the result with the structure and thermal behavior analysis. The TGA results showed high stability of lignin up to around 400°C. Main degraded compounds of all samples were phenol, vanillin, catechol, and guaiacol. This finding suggested that not only lignin which caused high BOD and COD could potentially be isolated for value added product but also the discharge quality could be improved. In addition, different chemical processes effect residual lignin in black liquor and underscore the importance of lignin in black liquor as a potential material for renewable energy and chemical production.