Lignin Derivatives Research Articles

Recent Advancement and Emerging Applications of Lignin

Lignin is a significant renewable natural energy resource these days, used as an environmentally acceptable and sustainable alternative fossil fuel feedstock in a huge possibility of value-added products. Lignin is a polymeric molecule that possesses an aromatic unit structure, together with cellulose, and is a main component of the cell walls of plants. It is the byproduct of agriculture residues and biorefinery products and can be extracted from paper-pulp industries. Properties of lignin may differ depending on the extraction method and source and also on an aromatic ring as the main constituent of lignin in the structure. This rare composition of lignin makes it more valuable, allowing for value-added applications such as in the field of storage devices and energy harvesters. This review focuses on derivatives of lignin, structure and composition sources and characteristics, and its sustainable emerging application in various fields are discussed.

Enhancing Stability and Efficacy of Trichoderma Bio‐Control Agents Through Layer‐by‐Layer Encapsulation for Sustainable Plant Protection

AbstractAgricultural fungicide pollution poses a significant environmental challenge and causes adverse effects on human health. Therefore, strategies to limit fungicide usage are of paramount importance. Trichoderma fungi, due to their antagonistic activity against various pathogenic fungi, have shown potential as a sustainable alternative to chemical fungicides. However, bio‐control agents like Trichoderma are vulnerable to physical stimuli and show diminished efficacy during prolonged storage. To address these challenges, a mild and scalable encapsulation method for Trichoderma spores is introduced, employing a layer‐by‐layer (LbL) approach using biobased lignin derivatives. It is demonstrated that the LbL encapsulation technique significantly improved spore stability relative to naked spores, even under adverse conditions including extreme temperatures and prolonged exposure to Ultraviolet (UV) irradiation. Notably, encapsulated Trichoderma spores showed enhanced efficacy in cultivating tomato plants compared to naked spores. Additionally, the findings revealed that the in planta efficacy of encapsulated spores is dependent on the specific Trichoderma strain used. This study suggests that Trichoderma spores encapsulated with lignin through the LbL approach, are a promising and sustainable alternative to chemical fungicides with potential for commercialization.

Sensory signature of lignins, new generation of bio-based ingredients in cosmetics

Lignins represent a high interest in cosmetics as promising multifunctional ingredients. Despite this, uncovering the sensory profile of lignin-based emulsions has remained an unexplored frontier. This study aims to bridge this gap by employing expert sensory evaluation and instrumental characterization to assess the sensory attributes of lignin-based emulsions. A comparative analysis with commercial tinted products and discrimination among lignin derivatives were integral components of the research. Results underscored the distinctive sensory properties of lignin emulsions, exhibiting significantly higher “Integrity of shape” (7.0 ± 0.1) compared to commercial products (4.8 ± 0.1). Additionally, lignin emulsions displayed longer play-time until skin absorption (4.3 ± 0.1), contrasting with the quicker absorption of commercial products (2.7 ± 0.4) and their shorter play-time. Depending on application requirements, lignin derivatives offer formulators a versatile sensory toolbox. Discrimination of lignin emulsions on certain texture properties was achieved using various instrumental tools. Despite the complex formulation of commercial products compared to lignin emulsions, similar texture properties were observed, showcasing lignins' potential to replace multiple ingredients in tinted cosmetics. Beyond their established antioxidant, anti-UV, anti-bacterial, and emulsifying properties, this study reveals additional advantageous sensory properties of lignins, positioning them as promising plant-based sensory ingredients in sustainable cosmetic applications.

Ni/Ce co-doping metal–organic framework catalysts with oxygen vacancy for catalytic transfer hydrodeoxygenation of lignin derivatives vanillin

Exploring an advanced catalytic strategy for the high value utilization of lignin derived chemicals into value-added aromatics has attracted tremendous sights for green manufacturing. In this paper, a series of bifunctional 3D rod-shaped mesoporous NiCe metal–organic framework catalysts coupling with hydrogen-donner solvent were reported for the hydrodeoxygenation of vanillin to obtain 2-methoxy-4-methylphenol. Under the optimal conditions, 3Ni-Ce/C catalyst realized the highest conversion of vanillin (>95.0 %) and selectivity of 81.4 % in the absence of additional hydrogen pressure. The characterization results indicated that the interaction of metallic Ni and CeO2 promoted the generation of Ni-CeO2-x interface and oxygen vacancies (Ov), which could efficiently adsorb and activate aldehyde group of vanillin to obtain reactive intermediates. And then metallic Ni sites activated the hydrogen-donner solvent to form adsorbed H atoms, which then spilled over to the adjacent Ov to stabilized reactive intermediates. Whereafter, bifunctional 3D rod-shaped mesoporous NiCe metal–organic framework catalysts achieved the hydrodeoxygenation upgrading of vanillin to obtain 2-methoxy-4-methylphenol. Density functional theory (DFT) calculations further revealed that the synergistic effect of Ni-CeO2 and oxygen vacancies promoted the activation and dissociation of aldehyde group bond in vanillin, enhanced the ability of protonation hydrogenolysis. Additionally, 3Ni-Ce/C catalyst displayed robust activity for no less than four recycles, which provided a feasible method for the build of simultaneous utilization of lignin derivates to value-added fuels and chemicals.

Mechanistic Insights into Hydrodeoxygenation of Lignin Derivatives over Ni Single Atoms Supported on Mo2C

Mechanistic Insights into Hydrodeoxygenation of Lignin Derivatives over Ni Single Atoms Supported on Mo₂C

From waste to protein: a new strategy of converting composted distilled grain wastes into animal feed.

Distilled grain waste (DGW) is rich in nutrients and can be a potential resource as animal feed. However, DGW contains as much as 14% lignin, dramatically reducing the feeding value. White-rot fungi such as Pleurotus ostreatus could preferentially degrade lignin with high efficiency. However, lignin derivatives generated during alcohol distillation inhibit P. ostreatus growth. Thus, finding a new strategy to adjust the DGW properties to facilitate P. ostreatus growth is critical for animal feed preparation and DGW recycling. In this study, three dominant indigenous bacteria, including Sphingobacterium thermophilum X1, Pseudoxanthomonas byssovorax X3, and Bacillus velezensis 15F were chosen to generate single and compound microbial inoculums for DGW composting to prepare substrates for P. ostreatus growth. Compared with non-inoculated control or single microbial inoculation, all composite inoculations, especially the three-microbial compound, led to faster organic metabolism, shorter composting process, and improved physicochemical properties of DGW. P. ostreatus growth assays showed the fastest mycelial colonization (20.43 μg·g-1 ergosterol) and extension (9 mm/d), the highest ligninolytic enzyme activities (Lac, 152.68 U·g-1; Lip, 15.56 U·g-1; MnP, 0.34 U·g-1; Xylanase, 10.98 U·g-1; FPase, 0.71 U·g-1), and the highest lignin degradation ratio (30.77%) in the DGW sample after 12 h of composting with the three-microbial compound inoculation when compared to other groups. This sample was relatively abundant in bacteria playing critical roles in amino acid, carbohydrate, energy metabolism, and xenobiotic biodegradation, as suggested by metagenomic analysis. The feed value analysis revealed that P. ostreatus mycelia full colonization in composted DGW led to high fiber content retention and decreased lignin content (final ratio of 5% lignin) but elevated protein concentrations (about 130 g·kg-1 DM). An additional daily weight gain of 0.4 kg/d was shown in cattle feeding experiments by replacing 60% of regular feed with it. These findings demonstrate that compound inoculant consisting of three indigenous microorganisms is efficient to compost DGW and facilitate P. ostreatus growth. P. ostreatus decreased the lignin content of composted DGW during its mycelial growth, improving the quality of DGW for feeding cattle.

Pathway and enzyme engineering for the bioconversion of lignin derivatives into homoeriodictyol in Saccharomyces cerevisiae

The innovative bioconversion route of lignin derivatives to homoeriodictyol meets the atom-economic concept, and paves a green, sustainable way for both the valorization of lignin and the production of valuable flavonoids.

Integrated Conversion of Lignocellulosic Biomass to Bio-Based Amphiphiles using a Functionalization-Defunctionalization Approach.

Concerns over the sustainability and end-of-life properties of fossil-derived surfactants have driven interest in bio-based alternatives. Lignocellulosic biomass with its polar functional groups is an obvious feedstock for surfactant production but its use is limited by process complexity and low yield. Here, we present a simple two-step approach to prepare bio-based amphiphiles directly from hemicellulose and lignin at high yields (29 % w/w based on the total raw biomass and >80 % w/w of these two fractions). Acetal functionalization of xylan and lignin with fatty aldehydes during fractionation introduced hydrophobic segments and subsequent defunctionalization by hydrogenolysis of the xylose derivatives or acidic hydrolysis of the lignin derivatives produced amphiphiles. The resulting biodegradable xylose acetals and/or ethers, and lignin-based amphiphilic polymers both largely retained their original natural structures, but exhibited competitive or superior surface activity in water/oil systems compared to common bio-based surfactants.

Integrated Conversion of Lignocellulosic Biomass to Bio‐Based Amphiphiles using a Functionalization‐Defunctionalization Approach

AbstractConcerns over the sustainability and end‐of‐life properties of fossil‐derived surfactants have driven interest in bio‐based alternatives. Lignocellulosic biomass with its polar functional groups is an obvious feedstock for surfactant production but its use is limited by process complexity and low yield. Here, we present a simple two‐step approach to prepare bio‐based amphiphiles directly from hemicellulose and lignin at high yields (29 % w/w based on the total raw biomass and >80 % w/w of these two fractions). Acetal functionalization of xylan and lignin with fatty aldehydes during fractionation introduced hydrophobic segments and subsequent defunctionalization by hydrogenolysis of the xylose derivatives or acidic hydrolysis of the lignin derivatives produced amphiphiles. The resulting biodegradable xylose acetals and/or ethers, and lignin‐based amphiphilic polymers both largely retained their original natural structures, but exhibited competitive or superior surface activity in water/oil systems compared to common bio‐based surfactants.

Сорбционно-структурные свойства аэрогельных материалов на основе биополимеров

Nowadays aerogel materials (AM) are successfully used as entero- and applicative sorbents to eliminate excessive amounts of heavy metals and toxins from living organisms. Natural biopolymers alginate and chitosan, as well as various lignin derivatives are an inexhaustible raw material base for the creation of AM. A significant number of sorption materials and wound coatings of various types have been developed on their basis, which is associated not only with a wide range of physicochemical properties of these polymers and their already proven biomedical activity, but also with the prevalence and renewability of raw material sources for the production of these polymers, ease of extraction, the possibility of achieving a high degree of purification and relatively low price. The key stage in the AM synthesis is the formation of a strong hydrogel which is the AM framework. One of the technological methods is to obtain interpolyelectrolyte solid hydrogel. The paper proposes two different packaging models for the formation of the structure of interpolyelectrolyte complexes (IPEC) based on biopolymers pairs: sodium alginate (ALNa)–chitosan (CT) and sodium lignosulfonate (LSNa)–CT. The first model is a block model, in which the structure is formed due to ionic bonds between the carboxyl groups of ALNa and amino groups of CT, as well as a cooperative system of hydrogen bonds and dispersion interactions. The second model is an aggregation-tubular model, the structure of which is formed through ionic bonds between sulfogroups (within the rod-shaped supramolecular structures of LSNa) and amino groups of CT, as well as hydrogen bonds and dispersion interactions. Upon the process of IPEC drying under supercritical (SC-) conditions, strong phase contacts are formed, and the changes in the gel structure become irreversible. As a result, hydrophobic micro- and mesoporous two-component AMs differing in internal structure were obtained. AM ALNa–CT are characterized by fibrillar structure, and LSNa–CT – by structural elements of spherical shape. The obtained AM ALNa–CT and LSNa–CT have high sorption activity towards water and a wide range of heavy metals and low molecular weight toxins. The purpose of the work is to study the structural and sorption properties of AM based on biopolymers of various structural organization. A significant increase in the sorption activity of AM ALNa–CT in comparison with LSNa–CT is apparently due to their different supramolecular structure. There is a combination of several sorption mechanisms such as wetting, absorption, diffusion, osmotic phenomena and chemical interaction due to the highly porous structure of AM and the presence of sorption-active centers. For citation: Brovko O.S., Palamarchuk I.A., Gorshkova N.A., Bogdanovich N.I., Ivakhnov A.D. Sorption and Structural Properties of Aerogel Materials Based on Biopolymers. Lesnoy Zhurnal = Russian Forestry Journal, 2023, no. 6, pp. 190–203. (In Russ.). https://doi.org/10.37482/0536-1036-2023-6-190-203

Effect of Polyphenolic Composition BP-C2 on Lung Carcinogenesis Induced by Urethane in Progeny of Irradiated Male BALB/c Mice.

We studied the effects of polyphenolic composition BP-C2, comprising molybdenum with lignin derivatives, on lung carcinogenesis induced by urethane in the progeny of F0 male BALB/c mice preconceptionally exposed to radiation in a dose of 1 Gy. The multiplicity of lung tumors in the progeny of irradiated mice was higher than in the progeny of non-irradiated male parents by 50% in females and 43% in males (p<0.05). In F1 mice (progeny of irradiated F0 male parents treated with BP-C2), the multiplicity of lung tumors was also higher, but this increase was less pronounced: 35% in females (p=0.3852) and 23% in males (p=0.0766). We have demonstrated that administration of BP-C2 to irradiated parents (F0) efficiently inhibits carcinogenesis in their F1 progeny. The use of BP-C2 in irradiated male parents and their progeny not only reduced the multiplicity of tumors, but also normalized body weights in the F1 progeny. Our study demonstrates potential of the polyphenolic composition BP-C2 for chemoprophylaxis of radiation-induced transgenerational carcinogenesis.

Heteropolyacids promoted MOF-derived high-performance Co(H4)@C-HPW0.25 catalysts for catalytic transfer hydrogenation of vanillin in mild condition

Catalytic transfer hydrogenation (CTH) was recognized as a promising technique for converting various lignin derivatives to fuels and high-value compounds in heterogeneous systems. Herein, Co@C catalysts with diverse organic ligands, Keggin-type heteropolyacids, acid addition quantities, and metal/organic ligand molar ratios were synthesized via one-pot hydrothermal processes and carbonization methods. The optimized catalyst demonstrated highly efficient active hydrogen generation from isopropanol and the best conversion (100 %) for vanillin (VAN) hydrodeoxygenation (HDO) with 90 % 2-methoxy-4-methylphenol (MMP) yield at 180 °C for one hour under mild conditions of 0 MPa N2 (hydrogen-free circumstance), which were strongly connected to the higher specific surface area (154.45 m2/g), acidic site density (4.67 mmol/g), and stronger metal-P interactions of the Co(H4)@C-HPW0.25 catalyst. The findings in this work provided an advanced thinking for designing high-performance non-noble-metal catalysts that could be applied in the catalytic HDO transformation of various biomass derivatives into green fuel and chemicals under mild circumstances.

Straw mulching decreased the contribution of Fe-bound organic carbon to soil organic carbon in a banana orchard

The association between iron (Fe) oxides (Fe-O) and organic carbon is a vital mechanism for the long-term accumulation and stabilization of soil organic carbon (SOC). To thoroughly explore the impacts of straw mulching on Fe-bound organic carbon (Fe-OC), we conducted a mulching application experiment in a 2-year no-tillage banana orchard. Two treatments (a 2-year straw mulching treatment and no straw return treatment) were established using a randomized complete block design. The Fe-OC and SOC pools in the surface soil were determined, and the results showed that straw mulching significantly increased the SOC contents by 34.02 %, and soil Fe-OC accounted for approximately 12.24 %–25.34 % of the SOC. Compared with the control treatment, straw mulching significantly decreased the Fe-OC contents and their contribution to SOC, which may have been due to soil dithionite-extractable Fe oxide (Fed) contents, the abundance of the Acidibacter, and α-glucosidase activities. Synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy indicated that straw mulching increased the colocalization between cellulose/hemicelluloses and peptides, and the relationships among lignin, Fe-O, and peptides became stronger than those in the CK treatment. These findings imply that straw mulching may decrease Fe-OC pools through various physicochemical and microbial mechanisms, these soil Fe-OC contents may be preserved as lignin derivatives and microbial-derived organic compounds.

Optimizing pyrolysis parameters and product analysis of a fluidized bed pilot plant for Leucaena leucocephala biomass

This study aimed to optimize the production of bio-oil from Leucaena leucocephala wood using a fluidized bed reactor. Response surface methodology was used to optimize the fast pyrolysis through three operational parameters: pyrolysis temperature, nitrogen flow rate, and temperature of the first condensation stage. The optimum conditions obtained for bio-oil production were 500 °C, 26.4 L min–1, that is, about 3.3 times the minimum fluidization flow, and 80 °C, respectively. The bio-oil obtained under optimum conditions was of good quality and did not require further treatment. Physical properties of the bio-oil were analysed according to ASTM D7544-12. In addition, the chemical composition of the non-condensed gases and bio-oil were identified using GC–MS. The non-condensed gases were found to contain mainly ketones and lignin derivatives, while the bio-oil contained cyclic ketones, alcohol ethers, aromatic alcohols, and lignin derivatives. The study found that increasing the pyrolysis temperature did not significantly increase the yield of H2 and CO for syngas production. Regarding the solid obtained, a large amount of unreacted material (66.7 wt.%) is generated at 400 °C, and as the temperature is increased, a high-quality biochar is obtained.

Thermoplastic Polymer from Lignin: Creating an Extended Polyamide Network through Reactive Kraft Lignin Derivatives.

Thermoplastic polymers have many desirable properties for consumer applications and are complemented by efficient thermal processing techniques, reducing the cost of manufacturing. Lignin exists as an immense biobased carbon source but has largely been researched for its use in thermoset materials due to its own cross-linked, polyfunctional nature. In this study, a new reaction design is employed to create a thermoplastic polyamide network incorporating lignin that is tested to be 99% biobased carbon by radiocarbon analysis. Chemical analysis reveals the nature of lignin incorporation based on chain extension and cross-linking models. The thermal and rheological properties of the new polymers are thoroughly investigated to demonstrate the higher melt-strength capability of the lignin-based polymers facilitating their use in modern processing equipment. This analysis results in finding an optimal lignin loading ratio in the polymer composition reflected by improved tensile strength and stiffness. The results point to a promising polymer design for applying industrial kraft lignin in high-value thermoplastic polymer applications.

Efficient preparation of polyethylene glycol (PEG)-modified lignin from steam exploded hardwood biomass

The structures and characteristics of lignin derivatives prepared from steam exploded beech under alkali delignification and acid catalyzed polyethylene glycol (PEG) solvolysis were studied in detail. An efficient method for directly isolating PEG-modified lignin from wood was proposed to improve its thermal stability. The effects of steam explosion (SE) parameters and delignification process on lignin structure were studied by high performance anion exchange chromatograph, fourier transform infrared spectroscopy (FTIR), heteronuclear single quantum coherence (HSQC) NMR spectroscopies, ultraviolet and visible spectrophotometry, size exclusion chromatography (SEC) and thermogravimetric analysis (TGA). The results showed that SE pretreatment can greatly promote the yield of PEG-modified lignin. The PEG-modified lignin, isolated from steam exploded wood at 210 °C for 2.5 min, was ∼14% yield. The PEG moiety was located at the alpha carbon position of the β-O-4 linkage. The PEG-modified lignin exhibited improved thermal properties with a maximum weight loss temperature (Tdmax) greater than 380 ℃, and a degradation starting temperature (Tdst) in the range of 258–277 °C, met the temperature for polymer processing and contribute to improve the added value of lignin.

Lignin Functionalized with Catechol for Large‐Scale Organic Electrodes in Bio‐Based Batteries

Lignin, obtained as a waste product in huge quantities from the large‐scale cellulose processing industries, holds a great potential to be used as sustainable electrode material for large‐scale electroactive energy storage systems. The fixed number of redox‐active phenolic groups present within the lignin structure limits the electrochemical performance and the total energy storage capacity of the lignin‐based electrodes. Herein, the way to enhance the charge storage capacity of lignin by incorporating additional small catechol molecules into the lignin structure is demonstrated. The catechol derivatives are covalently attached to the lignin via aromatic electrophilic substitution reaction. The increased phenolic groups in all functionalized lignin derivatives notably increase the values of capacitance compared to pristine lignin. Further, solvent fractionation of lignin followed by functionalization using catechol boosts three times the charge capacity of lignin electrode.

Glycerol-based liquefied palm kernel shell product and its blend with citric acid as bio-based wood adhesive

Concerns for the environment and for human health have become critical factors that motivate creating bio-based wood adhesives. Therefore, this study proposes replacing toxic chemicals with alternative adhesives. In the first step, glycerol was added to the natural phenolic compounds from liquefaction of palm kernel shell (PKS), having a high content of lignin. The obtained glycerol-based liquefied PKS, and its blend with citric acid, were tested for bonding in a study on the effects of hot-pressing conditions (temperature and time). The results revealed that the liquefaction system in this study achieved an 83% conversion of the PKS components into glycerol-based liquefaction. According to the Fourier transform infrared and carbon-13 nuclear magnetic resonance analyses, the glycerol-based PKS contained lignin derivatives and furan products. This accounted for its great performance in bonding rubberwood veneers. The tensile shear strength was improved by blending with 15% citric acid, especially when applying the high 190 °C pressing temperature for 15 min.

Slurry co-hydroprocessing of Kraft lignin and pyrolysis oil over unsupported NiMoS catalyst: A strategy for char suppression

Pyrolysis oil (PO) assisted Kraft lignin (KL) liquefaction over an unsupported NiMoS catalyst in a paraffin solvent was explored in this work. A paraffin solvent was used to represent hydrogenated vegetable oil (HVO) which is a biofuel. We have for the first time showed that when co-processing Kraft lignin with pyrolysis oil in a paraffin solvent the char formation could be completely suppressed. The complex composition of PO, containing various compounds with different functional groups, was able to aid the depolymerization pathways of lignin by obstructing the condensation path of reactive lignin derivatives. To further understand the role of different functional groups present in pyrolysis oil during lignin liquefaction, we investigate the co-hydroprocessing of Kraft lignin with various oxygenate monomers using unsupported NiMoS. 4-propylguaiacol (PG) was found to be the most efficient monomer for stabilizing the reactive lignin intermediates, resulting in a low char yield (3.7%), which was 4 times lower than the char production from Kraft lignin hydrotreatment alone. The suppressed rate of lignin fragment repolymerization can be attributed to the synergistic effect of functional groups like hydroxyl (-OH), methoxy (-OCH3), and propyl (-C3H7) groups present in PG. These groups were found to be able to stabilize the lignin depolymerized fragments and blocked the repolymerization routes enabling efficient lignin depolymerization. It was found that the presence of a co-reactant like PG during the heating period of the reactor acted as a blocking agent facilitating further depolymerization routes. Finally, a reaction network is proposed describing multiple routes of lignin hydroconversion to solid char, lignin-derived monomers, dimers, and oligomers, explaining why the co-processing of pyrolysis oil and Kraft lignin completely suppressed the solid char formation.

Catalytic hydroconversion of guaiacol and a poplar lignin derivate to cyclanes over Ni20%/β25

Upgrading lignin derivatives (LDs) to cyclanes by catalytic hydroconversion facilitates the value-added utilizations. Ni20%/β25 was prepared via a deposition-precipitation method and used for catalytically hydroconverting guaiacol and a poplar lignin derivate (PLD). Guaiacol was completely converted to cyclohexane (CH) as the main product in the yield of 93.3 mol% at 220 °C under initial hydrogen pressure of 4 MPa for 2 h, while the PLD was significantly converted to cyclanes over Ni20%/β25 for 8 h. Density functional theory combined with experiments explained the related mechanisms, i.e., H2 was activated to H…H, which was split to relatively mobile H+ and immobile H- over Ni20%/β25. H…H transfer to benzene ring (BR) leads to BR hydrogenation and subsequent H+ transfer to the oxygen atom in -OCH3 and -OH connected to the hydrogenated BR induces the demethoxylation and dehydroxylation.