Tunable and functional deep eutectic solvents for lignocellulose valorization

Choline chloride-based deep eutectic solvents as plasticizer and active agent in chitosan films

The growing concern over extending the shelf life of food products, coupled with the escalating environmental impact of synthetic plastic waste, has fuelled a quest for bio-based alternatives in packaging research. In response to this pressing need, our study delves into the synthesis of chitosan-based films incorporating a deep eutectic solvents (DES). Choline chloride and diverse hydrogen bond donors were used as plasticizers, we also explored the active properties of DES integrated into the chitosan (Ch) matrix. The Ch-based films with chlorine chloride: citric acid can prevent the mold spotting up to 29 days longer in comparison to bread wrapped in polyethylene films (PE). The obtained Ch/DES films exhibited mechanical properties comparable to conventional PE (e.g., up to tensile strength of 26 MPa and up to 210% in case of elongation at break). This synthesis approach represents a significant stride towards environmentally friendly packaging materials, aligning with the principles of green chemistry.

A designed ZrOCl2/ethylene glycol deep eutectic solvent for efficient lignocellulose valorization

Deep eutectic solvents (DESs) hold great potential in biorefining because they can efficiently deconstruct the recalcitrant structure of lignocellulose. In particular, inorganic salts with Lewis acids have been proven to be effective at cleaving lignin-carbohydrate complexes. Herein, a Zr-based DES system composed of metal chloride hydrate (ZrOCl2·8H2O) and ethylene glycol (EG) was designed and used for poplar powder pretreatment. Zr4+-based salts provide sufficient acidity for lignocellulose depolymerization. The acidity of the DES was analysed by the Kamlet-Taft solvatochromic parameter, and the results demonstrated that the acidity can be regulated by the DES composition. Under the optimum conditions (ZrOCl2·8H2O:EG molar ratio of 1:2), the DES pretreatment removes nearly 100 % hemicellulose and 94.7 % lignin. The recovered lignin exhibited a low polydispersity of 1.7. The cellulose residues deliver an efficiency of 94.4 % upon enzymatic digestion. Moreover, the DES can be easily recovered with high yield and purity, and the recycled DES still maintains high delignification and enzymatic hydrolysis efficiencies. The proposed DES pretreatment technology is promising for biomass valorization.

A flexible, stretchable and wearable strain sensor based on physical eutectogels for deep learning-assisted motion identification

Physical eutectogels as a newly emerging type of conductive gel have gained extensive interest for the next generation multifunctional electronic devices. Nevertheless, some obstacles, including weak mechanical performance, low self-adhesive strength, lack of self-healing capacity, and low conductivity, hinder their practical use in wearable strain sensors. Herein, lignin as a green filler and a multifunctional hydrogen bond donor was directly dissolved in a deep eutectic solvent (DES) composed of acrylic acid (AA) and choline chloride, and lignin-reinforced physical eutectogels (DESL) were obtained by the polymerization of AA. Due to the unique features of lignin and DES, the prepared DESL eutectogels exhibit good transparency, UV shielding capacity, excellent mechanical performance, outstanding self-adhesiveness, superior self-healing properties, and high conductivity. Based on the aforementioned integrated functions, a wearable strain sensor displaying a wide working range (0-1500%), high sensitivity (GF = 18.15), rapid responsiveness, and excellent stability and durability (1000 cycles) and capable of detecting diverse human motions was fabricated. Additionally, by combining DESL sensors with a deep learning technique, a gesture recognition system with accuracy as high as 98.8% was achieved. Overall, this work provides an innovative idea for constructing multifunction-integrated physical eutectogels for application in wearable electronics.

Hydrogen-transfer strategy in lignin refinery: Towards sustainable and versatile value-added biochemicals

Lignin, the most prevalent natural source of polyphenols on Earth, offers substantial possibilities for the conversion into aromatic compounds, which is critical for attaining sustainability and carbon neutrality. The hydrogen-transfer method has garnered significant interest owing to its environmental compatibility and economic viability. The efficacy of this approach is contingent upon the careful selection of catalytic and hydrogen-donating systems that decisively affect the yield and selectivity of the monomeric products resulting from lignin degradation. This paper highlights the hydrogen-transfer technique in lignin refinery, with a specific focus on the influence of hydrogen donors on the depolymerization pathways of lignin. It delineates the correlation between the structure and activity of catalytic hydrogen-transfer arrangements and the gamut of lignin-derived biochemicals, utilizing data from lignin model compounds, separated lignin, and lignocellulosic biomass. Additionally, the paper delves into the advantages and future directions of employing the hydrogen-transfer approach for lignin conversion. In essence, this concept investigation illuminates the efficacy of the hydrogen-transfer paradigm in lignin valorization, offering key insights and strategic directives to maximize lignin's value sustainably.

Lattice Strain Engineering on Metal-Organic Frameworks by Ligand Doping to Boost the Electrocatalytic Biomass Valorization

As an efficient and environmental-friendly strategy, electrocatalytic oxidation can realize biomass lignin valorization by cleaving its aryl ether bonds to produce value-added chemicals. However, the complex and polymerized structure of lignin presents challenges in terms of reactant adsorption on the catalyst surface, which hinders further refinement. Herein, NiCo-based metal-organic frameworks (MOFs) are employed as the electrocatalyst to enhance the adsorption of reactant molecules through π-π interaction. More importantly, lattice strain is introduced into the MOFs via curved ligand doping, which enables tuning of the d-band center of metal active sites to align with the reaction intermediates, leading to stronger adsorption and higher electrocatalytic activity toward bond cleavage within lignin model compounds and native lignin. When 2'-phenoxyacetophenone is utilized as the model compound, high yields of phenol (76.3%) and acetophenone (21.7%) are achieved, and the conversion rate of the reactants reaches 97%. Following pre-oxidation of extracted poplar lignin, >10 kinds of phenolic compounds are received using the as-designed MOFs electrocatalyst, providing ≈12.48% of the monomer, including guaiacol, vanillin, eugenol, etc., and p-hydroxybenzoic acid dominates all the products. This work presents a promising and deliberately designed electrocatalyst for realizing lignin valorization, making significant strides for the sustainability of this biomass resource.

Fractionation of oil palm fronds using ethanol-assisted deep eutectic solvent: Influence of ethanol concentration on enhancing enzymatic saccharification and lignin β-O-4 content

Numerous fractionation methods have been developed in recent years for separating components such as cellulose, hemicellulose, and lignin from lignocellulosic biomass wastes. Deep eutectic solvents (DES) have recently been widely investigated as captivating green solvents for biomass fractionation. However, most acidic-based deep eutectic solvent fractionation produces condensed lignin with low β-O-4 content. Besides, most DESs exhibit high viscosity, which results in poor mass transfer properties. This study aimed to address the challenges above by incorporating ethanol into the deep eutectic solvent at various concentrations (10-50 wt%) to fractionate oil palm fronds at a mild condition, i.e., 80 °C, 1 atm. Cellulose residues fractionated with ethanol-assisted deep eutectic solvent showed a maximum glucose yield of 85.8% when 20 wt% of ethanol was incorporated in the deep eutectic solvent, significantly higher than that achieved by pure DES (44.8%). Lignin extracted with ethanol-assisted deep eutectic solvent is lighter in color and higher in β-O-4 contents (up to 44 β-O-4 per 100 aromatic units) than pure DES-extracted lignin. Overall, this study has demonstrated that incorporating ethanol into deep eutectic solvents could enhance the applicability of deep eutectic solvents in the complete valorization of lignocellulosic biomass. Highly enzymatic digestible cellulose-rich solid and β-O-4-rich lignin attained from the fractionation could serve as sustainable precursors for the production of biofuels.

ALACEN: A Holistic Herbaceous Biomass Fractionation Process Attaining a Xylose-Rich Stream for Direct Microbial Conversion to Bioplastics

Lignocellulose biorefining is a promising technology for the sustainable production of chemicals and biopolymers. Usually, when one component is focused on, the chemical nature and yield of the others are compromised. Thus, one of the bottlenecks in biomass biorefining is harnessing the maximum value from all of the lignocellulosic components. Here, we describe a mild stepwise process in a flow-through setup leading to separate flow-out streams containing cinnamic acid derivatives, glucose, xylose, and lignin as the main components from different herbaceous sources. The proposed process shows that minimal degradation of the individual components and conservation of their natural structure are possible. Under optimized conditions, the following fractions are produced from wheat straw based on their respective contents in the feed by the ALkaline ACid ENzyme process: (i) 78% ferulic acid from a mild ALkali step, (ii) 51% monomeric xylose free of fermentation inhibitors by mild ACidic treatment, (iii) 82% glucose from ENzymatic degradation of cellulose, and (iv) 55% native-like lignin. The benefits of using the flow-through setup are demonstrated. The retention of the lignin aryl ether structure was confirmed by HSQC NMR, and this allowed monomers to form from hydrogenolysis. More importantly, the crude xylose-rich fraction was shown to be suitable for producing polyhydroxybutyrate bioplastics. The direct use of the xylose-rich fraction by means of the thermophilic bacteria Schlegelella thermodepolymerans matched 91% of the PHA produced with commercial pure xylose, achieving 138.6 mgPHA/gxylose. Overall, the ALACEN fractionation method allows for a holistic valorization of the principal components of herbaceous biomasses.

Efficient extraction of lignin from moso bamboo by microwave-assisted ternary deep eutectic solvent pretreatment for enhanced enzymatic hydrolysis

Applications of deep eutectic solvent (DES) systems to separate lignocellulosic components are of interest to develop environmentally friendly processes and achieve efficient utilization of biomass. To enhance the performance of a binary neutral DES (glycerol:guanidine hydrochloride), various Lewis acids (e.g., AlCl3·6H2O, FeCl3·6H2O, etc.) were introduced to synthesize a series of ternary DES systems; these were coupled with microwave heating and applied to moso bamboo. Among the ternary DES systems evaluated, the FeCl3-based DES effectively removed lignin (81.17%) and xylan (85.42%), significantly improving enzymatic digestibility of the residual glucan and xylan (90.15% and 99.51%, respectively). Furthermore, 50.74% of the lignin, with high purity and a well-preserved structure, was recovered. A recyclability experiment showed that the pretreatment performance of the FeCl3-based DES was still basically maintained after five cycles. Overall, the microwave-assisted ternary DES pretreatment approach proposed in this study appears to be a promising option for sustainable biorefinery operations.

Screening of cellulose-degrading bacteria and optimization of cellulase production from Bacillus cereus A49 through response surface methodology

Cellulose-degrading microorganisms hold immense significance in utilizing cellulose resources efficiently. The screening of natural cellulase bacteria and the optimization of fermentation conditions are the hot spots of research. This study meticulously screened cellulose-degrading bacteria from mixed soil samples adopting a multi-step approach, encompassing preliminary culture medium screening, Congo red medium-based re-screening, and quantification of cellulase activity across various strains. Particularly, three robust cellulase-producing strains were identified: A24 (MT740356.1 Brevibacillus borstelensis), A49 (MT740358.1 Bacillus cereus), and A61 (MT740357.1 Paenibacillus sp.). For subsequent cultivation experiments, the growth curves of the three obtained isolates were monitored diligently. Additionally, optimal CMCase production conditions were determined, keeping CMCase activity as a key metric, through a series of single-factor experiments: agitation speed, cultivation temperature, unit medium concentration, and inoculum volume. Maximum CMCase production was observed at 150 rpm/37 °C, doubling the unit medium addition, and a 5 mL inoculation volume. Further optimization was conducted using the selected isolate A49 employing response surface methodology. The software model recommended a 2.21fold unit medium addition, 36.11 °C temperature, and 4.91 mL inoculant volume for optimal CMCase production. Consequently, three parallel experiments were conducted based on predicted conditions consistently yielding an average CMCase production activity of 15.63 U/mL, closely aligning with the predicted value of 16.41 U/mL. These findings validated the reliability of the model and demonstrated the effectiveness of optimized CMCase production conditions for isolate A49.

Enhancing bioavailable carbon sources and minimizing ammonia emissions in distillery sludge and distiller's grains waste co-composting through deep eutectic solvent addition

This study introduced two deep eutectic solvents, ChCl/oxalic acid (CO) and ChCl/ethylene glycol (CE), into a 34-day co-composting process of distillery sludge and distiller's grains waste to address challenges related to NH3 emissions. The addition of DES increased dissolved organic carbon by 68% to 92%, offering more utilizable carbon for microorganisms. SYTO9/PI staining and enzyme activity tests showed the CE group had higher bacterial activity and metabolic levels during the thermophilic phase than the control. Bacterial community analysis revealed that early dominance of Lactobacillus and Lysinibacillus in CE accelerated the onset of the thermophilic phase, reduced pile pH, and significantly decreased urease production by reducing Ureibacillus. Consequently, CE treatment substantially dropped NH3 emissions by 73% and nitrogen loss by 54%. Besides, CE fostered a more abundant functional microbial community during the cooling and maturation phases, enhancing deep degradation and humification of organic matter.

Interpretation of the phenolation and structural changes of lignin in a novel ternary deep eutectic solvent

Deep eutectic solvents (DES) are promising green solvents for depolymerization and reconstruction of lignin. Revealing the transformations of lignin during DES treatment is beneficial for high potential lignin applications. In this study, bagasse lignin was treated with a binary DES and three ternary DESs, respectively. The results showed that net hydrogen bonding acidity(α-β) value of DES was positively correlated to the increment of phenolic hydroxyl of lignin, and the ternary DES of choline chloride-formic acid-oxalic acid (ChCl-FA-OA) exhibited the best phenolation performances. The phenolic hydroxyl content of ChCl-FA-OA treated lignin was increased by 50.4 %, reaching 2.41 mmol/g under optimum conditions (120 °C, 4 h, ChCl-FA-OA = 1:2:1). Moreover, it was found that the cleavage of β-O-4' aryl ether bond and ester bond were dominant reactions during the treatment, accompanied by condensation reactions. Additionally, the obtained lignin oil contained various syringyl and guaiacyl derived phenolic compounds. Especially, the content of acetovanillone in lignin oil reached 29.94 %, much higher than in previous studies. Finally, the degradation mechanism of lignin in ChCl-FA-OA system was proposed. The present work provided insights into the relationship between lignin phenolation and DES properties. The novel ChCl-FA-OA system can achieve efficient lignin depolymerization, and convert lignin biomass into value-added chemical products.

A state-of-the-art review on plant-derived cellulose-based green hydrogels and their multifunctional role in advanced biomedical applications

The most prevalent carbohydrate on Earth is cellulose, a polysaccharide composed of glucose units that may be found in diverse sources, such as cell walls of wood and plants and some bacterial and algal species. The inherent availability of this versatile material provides a natural pathway for exploring and identifying novel uses. This study comprehensively analyzes cellulose and its derivatives, exploring their structural and biochemical features and assessing their wide-ranging applications in tissue fabrication, surgical dressings, and pharmaceutical delivery systems. The use of diverse cellulose particles as fundamental components gives rise to materials with distinct microstructures and characteristics, fulfilling the requirements of various biological applications. Although cellulose boasts substantial potential across various sectors, its exploration has predominantly unfolded within industrial realms, leaving the biomedical domain somewhat overlooked in its initial stages. This investigation, therefore, endeavors to shed light on the contemporary strides made in synthesizing cellulose and its derivatives. These innovative techniques give rise to distinctive attributes, presenting a treasure trove of advantages for their compelling integration into the intricate tapestry of biomedical applications.

Promising cellulose-based functional gels for advanced biomedical applications: A review

Novel biomedical materials provide a new horizon for the diagnosis/treatment of diseases and tissue repair in medical engineering. As the most abundant biomass polymer on earth, cellulose is characterized by natural biocompatibility, good mechanical properties, and structure-performance designability. Owing to these outstanding features, cellulose as a biomacromolecule can be designed as functional biomaterials via hydrogen bonding (H-bonding) interaction or chemical modification for human tissue repair, implantable tissue organs, and controlling drug release. Moreover, cellulose can also be used to construct medical sensors for monitoring human physiological signals. In this study, the structural characteristics, functionalization approaches, and advanced biomedical applications of cellulose are reviewed. The current status and application prospects of cellulose and its functional materials for wound dressings, drug delivery, tissue engineering, and electronic skin (e-skin) are discussed. Finally, the key technologies and methods used for designing cellulosic biomaterials and broadening their application prospects in biomedical fields are highlighted.

Environmentally sustainable ethyl levulinate synthesis from delignified sugarcane bagasse using ternary eutectic solvent under MW-xenon irradiation: engine performance and emission assessment

For the first time, a synergistic energy-efficient combination of microwave-xenon (MW-XE) irradiations in presence of photoactive ternary acidic deep eutectic solvents (TADES) has been applied for intensification of ethyl levulinate synthesis from delignified sugarcane bagasse (DSB) under mild (90 min, 90 °C) and environmentally benign process conditions. The Taguchi orthogonal designed optimized conditions (20 W/cm3 of MW specific irradiation power input, 1 mol/mol of FeCl3 to citric acid ratio, 90 min of reaction time, 150 W of XE specific power input) rendered maximum 61.3 mol% of EL yield (selectivity: 87.70 [Formula: see text] 0.5%). Remarkably, synergistic effect of MW and XE irradiation significantly enhanced the EL yield (61.3 mol%) compared to the individual MW (34.52 mol%) and XE (22.67 mol%) irradiation at otherwise optimized reaction conditions. Moreover, the MWXE irradiated reactor (MWXER) exhibited a significant 79.10% increase in EL yield compared to the conventional thermal reactor (CTR), at the expense of 10% less energy consumption. The ethyl levulinate could be recovered efficiently through green protocol from reaction mix resulting in high purity (97 [Formula: see text] 0.5%) and TADES was sustainably reused in the process. The optimally generated product EL when blended (5 and 10 vol.%) with B10 and B20 (10% and 20% biodiesel-diesel blend) could provide 21-31% reduction in HC and 7.3-36% reduction in CO in comparison with petro-diesel. It was also explored that, at similar optimal parametric combinations, the TADES produced 29.5% greater EL yield in comparison with the standard ionic liquid BMIMCl. The life cycle environmental impact analysis (LCEIA) of the overall process revealed that the 5 vol.% EL blending with B10 contributed lowest environmental impacts mitigating marine ecotoxicity, human toxicity, fossil depletion, and climate change by 77.9%, 77.4%, 78.4% and 77.5%, respectively.

Preparation of uniform lignin/titanium dioxide nanoparticles by confined assembly: A multifunctional nanofiller for a waterborne polyurethane wood coating

We report a facile synthesis for lignin/titanium dioxide (TiO2) nanoparticles (LT NPs) at room temperature by confining assembly of lignin macromolecules. The LT NPs had a uniform nanosize distribution (average diameter ∼ 68 nm) and were directly employed as multifunctional nanofillers to reinforce a waterborne polyurethane wood coating (WBC). X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy revealed the mechanism by which formed TiO2 confined lignin assembly. The LT NPs considerably increased the tensile strength of a WBC film from 16.3 MPa to 28.1 MPa. The WBC-LT NPs exhibited excellent ultraviolet (UV) A and UVB blocking performances of 87 % and 98 %, respectively, while maintaining 94 % transmittance in the visible region. Incorporating LT NPs into the WBC enhanced the coating performance (the hardness, adhesion, and abrasion resistance) on wood substrates. A quantitative color and texture analysis revealed that the LT NPs increased the decorativeness of actual wooden products. After nearly 1800 h of UV irradiation, wood coated with the WBC-LT NPs exhibited good color stability, where the original color remained unchanged or even became brighter. In this study, value-added valorization of lignin is enabled by using organic-inorganic nanofillers and insights are gained into developing multifunctional WBCs.

Microwave-assisted extraction of cellulose and aromatic compounds from rose petals based on deep eutectic solvent

High-value utilization of agricultural wastes such as rose petals promotes the development of the dual carbon economy. In this study, rose petals were pretreated by microwave-assisted deep eutectic solvent (DES). Choline chloride-ethylene glycol (ChCl-EG) was used as the basis for the addition of P-toluenesulfonic acid (TsOH) or Ferric chloride (FeCl3). Forming ternary DESs, as well as designing quaternary DESs with a synergistic effect. The effects of different types of multicomponent DES on treating anthocyanins, cellulose, and lignin in rose flowers were explored. The results showed that the highest anthocyanin extraction of 173.71 mg/g and the highest lignin removal of 40.80 % could be achieved after tetrad DES pretreatment when the molar ratio was ChCl:EG:TsOH:FeCl3 = 1:2:0.3:0.3. The interaction energy between anthocyanins and DES was calculated using density functional theory (DFT), and the maximum was -543.14 kcal/mol. This study demonstrated that DES pretreatment can provide novel insights for the utilization of roses in high-value.

Aqueous amine enables sustainable monosaccharide, monophenol, and pyridine base coproduction in lignocellulosic biorefineries

Thought-out utilization of entire lignocellulose is of great importance to achieving sustainable and cost-effective biorefineries. However, there is a trade-off between efficient carbohydrate utilization and lignin-to-chemical conversion yield. Here, we fractionate corn stover into a carbohydrate fraction with high enzymatic digestibility and reactive lignin with satisfactory catalytic depolymerization activity using a mild high-solid process with aqueous diethylamine (DEA). During the fractionation, in situ amination of lignin achieves extensive delignification, effective lignin stabilization, and dramatically reduced nonproductive adsorption of cellulase on the substrate. Furthermore, by designing a tandem fractionation-hydrogenolysis strategy, the dissolved lignin is depolymerized and aminated simultaneously to co-produce monophenolics and pyridine bases. The process represents the viable scheme of transforming real lignin into pyridine bases in high yield, resulting from the reactions between cleaved lignin side chains and amines. This work opens a promising approach to the efficient valorization of lignocellulose.

Clean Synthetic Strategies to Biologically Active Molecules from Lignin: A Green Path to Drug Discovery

Deriving active pharmaceutical agents from renewable resources is crucial to increasing the economic feasibility of modern biorefineries and promises to alleviate critical supply-chain dependencies in pharma manufacturing. Our multidisciplinary approach combines research in lignin-first biorefining, sustainable catalysis, and alternative solvents with bioactivity screening, an in vivo efficacy study, and a structural-similarity search. The resulting sustainable path to novel anti-infective, anti-inflammatory, and anticancer molecules enabled the rapid identification of frontrunners for key therapeutic indications, including an anti-infective against the priority pathogen Streptococcus pneumoniae with efficacy in vivo and promising plasma and metabolic stability. Our catalytic methods provided straightforward access, inspired by the innate structural features of lignin, to synthetically challenging biologically active molecules with the core structure of dopamine, namely, tetrahydroisoquinolines, quinazolinones, 3-arylindoles and the natural product tetrahydropapaveroline. Our diverse array of atom-economic transformations produces only harmless side products and uses benign reaction media, such as tunable deep eutectic solvents for modulating reactivity in challenging cyclization steps.

Efficient separation and production of high-quality rubber, lignin nanoparticles and fermentable sugars from Eucommia ulmoides pericarp via deep eutectic solvent pretreatment

The natural barriers of lignocellulose hinder the separation of Eucommia ulmoides rubber (EUR) from Eucommia ulmoides pericarp (EUP), whereas traditional separation methods normally lead to the waste of Eucommia ulmoides lignocellulose resource and environmental pollution. In this study, an acidic deep eutectic solvent composed of lactic acid and ZnCl2 was developed as a pretreatment medium to reduce the separation barriers of EUR while producing lignin nanoparticles and fermentable sugars. Results showed that DES pretreatment could accelerate the extraction efficiency (91.0 %) and purity (>99 %) of EUR and maintain its chemical structure compared to the traditional alkaline and mechanical methods. Meanwhile, the regenerated nano-lignin showed excellent antioxidant activity (IC50 = 46.3 μg/mL) comparable to commercial antioxidant BHA. Besides, the enzymatic hydrolysis efficiency of EUP with DES pretreatment was significantly enhanced about 9 times than the control groups. Overall, the acidic DES pretreatment could be considered a promising pretreatment method for separation of high-quality EUR and valorization of lignocellulosic components.

Low-temperature pretreatment by AlCl3-catalyzed 1,4-butanediol solution for producing 'ideal' lignin with super-high content of β-O-4 linkages

High contents of internal β-O-4 linkages in lignin are critical for high-yield production of high-value aromatic monomers by depolymerization. However, it remains great challenge due to lack of suitable protection strategy. In this work, a very effective lignin-first strategy was developed to produce ideal lignin with a super high content of β-O-4 linkages (up to 72 %) from poplar, in which the pretreatment was undertaken at low temperatures of 90-130 °C with the use of AlCl3-catalyzed 1, 4-butanediol solution. 2D-HSQC NMR spectra revealed that lignin β-O-4 linkages were protected from etherification of the OH group by 1, 4-butanediol at the α position of lignin aliphatic chains. Besides, the OH groups at the γ position of lignin was also etherified, leading the formation of a structure of Ph-CH=CHCH2O(CH2)4OH. Interestingly, structure protection facilitated the formation of lignin nanoparticles via self-assembly (<100 nm). In addition, it was observed from pyrolysis results that addition of 1, 4-butanediol remarkably protected the structure of lignin by avoiding condensation, promoting the production of aromatics. The cellulose-rich fraction possessed a high cellulose digestibility of 91.64 % by enzymatic hydrolysis at a cellulase dosage of 15 FPU/g cellulose, approximately 6-fold untreated poplar (15.91 %). This low-temperature lignin-first strategy was of great importance for multi-products biorefining lignocellulose because it leads to the production of both lignin with super high content of β-O-4 linkages for depolymerization and highly digestible cellulose for sugar production.

Electrocatalytic Lignin Valorization into Aromatic Products via Oxidative Cleavage of Cα-Cβ Bonds

Lignin is the most promising candidate for producing aromatic compounds from biomass. However, the challenge lies in the cleavage of C-C bonds between lignin monomers under mild conditions, as these bonds have high dissociation energy. Electrochemical oxidation, which allows for mild cleavage of C-C bonds, is considered an attractive solution. To achieve low-energy consumption in the valorization of lignin, the use of highly efficient electrocatalysts is essential. In this study, a meticulously designed catalyst consisting of cobalt-doped nickel (oxy)hydroxide on molybdenum disulfide heterojunction was developed. The presence of molybdenum in a high valence state promoted the adsorption of tert-butyl hydroperoxide, leading to the formation of critical radical intermediates. In addition, the incorporation of cobalt doping regulated the electronic structure of nickel, resulting in a lower energy barrier. As a result, the heterojunction catalyst demonstrated a selectivity of 85.36% for cleaving the Cα-Cβ bond in lignin model compound, achieving a substrate conversion of 93.69% under ambient conditions. In addition, the electrocatalyst depolymerized 49.82 wt% of soluble fractions from organosolv lignin (OL), resulting in a yield of up to 13 wt% of aromatic monomers. Significantly, the effectiveness of the prepared electrocatalyst was also demonstrated using industrial Kraft lignin (KL). Therefore, this research offers a practical approach for implementing electrocatalytic oxidation in lignin refining.

Efficient extraction of nanocellulose from lignocellulose using aqueous butanediol fractionation to improve the performance of waterborne wood coating

The highly efficient extraction of cellulose from lignocellulose with an excellent yield of 95.2 % and purity of 96.7 % was demonstrated using acid-catalyzed fractionation with aqueous butanediol. This cellulose was subsequently transformed into cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) with specific dimensions and surface functional groups through various chemomechanical treatments. The average diameters of CNFs and CNCs produced by sulfuric acid hydrolysis-ultrasonication and deep eutectic solvent treatment-ultrasonication (DES-CNCs) were 29.7, 21.9 and 17.3 nm, respectively. The DES-CNCs were obtained in a good yield of 71 ± 1.27 wt% and exhibited a high zeta potential of -33.5 ± 2.51 mV following posthydrolysis and esterification during the DES treatment. These CNFs and CNCs were used as nanofillers in a waterborne wood coating (WWC), which significantly improved its dynamic viscosity and storage modulus. The addition of these materials also enhanced the mechanical strength of the WWC but had little effect on transmittance. Glossiness, hardness, abrasion resistance and adhesion strength were evaluated, and the DES-CNCs provided the greatest improvements at a low concentration. A plausible reinforcement mechanism was presented. This work provided an efficient cellulose extraction method and detailed structure elucidation of the nanocellulose together with suggestions for value-added applications of cellulosic nanofillers for reinforcing WWC.

Novel supramolecular deep eutectic solvent-enabled in-situ lignin protection for full valorization of all components of wheat straw

Lignin is usually deemed as an inhibitor to enzymatic hydrolysis of cellulose due to its physical barrier, non-productive adsorption, and steric hindrance. Herein, a novel supramolecular deep eutectic solvent (SUPRADES), comprising ethylene glycol and citric acid in 5:1 M ratio, and β-cyclodextrin (β-CD) in a concentration of 3.5% (w/w), was developed to be efficient for pretreating wheat straw. The delignification rate, cellulose enzymatic digestibility, and hemicellulose removal reached 90.45%, 97.36% and 87.24%, respectively, which may be attributed to the introduction of β-CD with superior ability of both adsorption and in-situ lignin protection to efficiently remove lignin with intact structure from cellulose surface. The mechanisms of high-efficiency lignin extraction/protection were systematically illustrated by adsorption kinetics. Moreover, Trichosporon cutaneum grown on the hemicellulose and cellulose fractions after pretreatment afforded 8.8 g total lipids from 100 g wheat straw. The green SUPARDES pretreatment strategy offers a new avenue for upgrading lignocellulose to biofuels.

Structure investigation of light-colored lignin extracted by Lewis acid-based deep eutectic solvent from softwood

Lignin is the most abundant natural phenolic polymer. However, the severe condensations of industrial lignin resulted in an undesirable apparent morphology and darker color, which hindered its application in the field of daily chemicals. Therefore, a ternary deep eutectic solvent is used to obtain lignin with light-color and low condensations from softwood. The results showed that the brightness value of lignin extracted from aluminum chloride-1,4-butanediol-choline chloride at 100 °C and 1.0 h was 77.9, and the lignin yield was 32.2 ± 0.6%. It is important that 95.8% of β-O-4 linkages (β-O-4 and β-O-4') was retained. Lignin is used to prepare sunscreens and is added to physical sunscreens at 5%, with SPF up to 26.95 ± 4.20. Meanwhile, enzyme hydrolysis experiments and reaction liquid composition tests were also conducted. In conclusion, a systematic understanding of this efficient process could facilitate high-value utilization of lignocellulosic biomass in industrial processes.

Recent advances in the application of alcohols in extracting lignin with preserved β-O-4 content from lignocellulosic biomass

Utilizing lignocellulosic biomass wastes to produce bioproducts is essential to address the reliance on depleting fossil fuels. However, lignin is often treated as a low-value-added component in lignocellulosic wastes. Valorization of lignin into value-added products is crucial to improve the economic competitiveness of lignocellulosic biorefinery. Monomers obtained from lignin depolymerization could be upgraded into fuel-related products. However, lignins obtained from conventional methods are low in β-O-4 content and, therefore, unsuitable for monomer production. Recent literature has demonstrated that lignins extracted with alcohol-based solvents exhibit preserved structures with high β-O-4 content. This review discusses the recent advances in utilizing alcohols to extract β-O-4-rich lignin, where discussion based on different alcohol groups is considered. Emerging strategies in employing alcohols for β-O-4-rich lignin extraction, including alcohol-based deep eutectic solvent, flow-through fractionation, and microwave-assisted fractionation, are reviewed. Finally, strategies for recycling or utilizing the spent alcohol solvents are also discussed.

Mechanism of enhanced enzymatic hydrolysis performance by ethanol assisted deep eutectic solvent pretreatment- from the perspective of lignin

Valorization of lignocellulose has received a lot of attention due to the abundance of lignocellulosics. It was showed that synergistic carbohydrate conversion and delignification could be achieved via ethanol assisted DES (choline chloride/lactic acid) pretreatment. To explore the reaction mechanism of lignin in the DES, milled wood lignin obtained from Broussonetia papyrifera was subjected to pretreatment at critical temperatures. The results suggested that ethanol assistance could contribute the incorporation of ethyl groups and reduce condensation structures of Hibbert's ketone. Adding ethanol at 150 °C not only decreased formation of condensed G unit (from 7.23% to 0.87%), but also removed J and S' substructures, thus effectively reducing the adsorption of lignin on cellulase, and promoting the glucose yield after enzymatic hydrolysis.

Novel dual-action vanillic acid pretreatment for efficient hemicellulose separation with simultaneous inhibition of lignin condensation

Aromatic acids play a selective role in the separation of hemicellulose. Phenolic acids have demonstrated an inhibitory effect on lignin condensation. In the current study, vanillic acid (VA), which combines the characteristics of aromatic and phenolic acids, is used to separate eucalyptus. The efficient and selective separation of hemicellulose is achieved simultaneously at 170 °C, 8.0% VA concentration, and 80 min. The separation yield of xylose increased from 78.80% to 88.59% compared to acetic acid (AA) pretreatment. The separation yield of lignin decreased from 19.32% to 11.19%. In particular, the β-O-4 content of lignin increased by 5.78% after pretreatment. The results indicate that VA, as a "carbon positive ion scavenger", it preferentially reacts with the carbon-positive ion intermediate of lignin. Surprisingly, the inhibition of lignin condensation is achieved. This study provides a new starting point for the development of an efficient and sustainable commercial technology by organic acid pretreatment.

Exploration of the interaction mechanism of lignocellulosic hybrid systems based on deep eutectic solvents

The interactions of three deep eutectic solvents (DES) choline chloride-glycerol (ChCl-GLY), ChCl-lactic acid (ChCl-LA) and ChCl-urea (ChCl-U) with cellulose-hemicellulose and cellulose-lignin hybrid systems were investigated using the simulated computational approach. Aiming to simulate DES pretreatment of real lignocellulosic biomass in nature. DES pretreatment could disrupt the original hydrogen bonding network structure among the lignocellulosic components and reconstruct the new DES-lignocellulosic hydrogen bonding network structure. ChCl-U had the highest intensity of action on the hybrid systems, removing 78.3% of the hydrogen bonds between cellulose-4-O-methyl Gluconic acid xylan (cellulose-Gxyl) and 68.4% of the hydrogen bonds between cellulose-Veratrylglycerol-b-guaiacyl ether (cellulose-VG), respectively. The increase of urea content facilitated the interaction between DES and lignocellulosic blend system. Finally, the addition of appropriate water (DES:H₂O = 1:5) and DES formed the new DES-water hydrogen bonding network structure more favorable for the interaction of DES with lignocellulose.

Laccase-catalyzed lignin depolymerization in deep eutectic solvents: challenges and prospects

Lignin has enormous potential as a renewable feedstock for depolymerizing to numerous high-value chemicals. However, lignin depolymerization is challenging owing to its recalcitrant, heterogenous, and limited water-soluble nature. From the standpoint of environmental friendliness and sustainability, enzymatic depolymerization of lignin is of great significance. Notably, laccases play an essential role in the enzymatic depolymerization of lignin and are considered the ultimate green catalysts. Deep eutectic solvent (DES), an efficient media in biocatalysis, are increasingly recognized as the newest and utmost green solvent that highly dissolves lignin. This review centers on a lignin depolymerization strategy by harnessing the good lignin fractionating capability of DES and the high substrate and product selectivity of laccase. Recent progress and insights into the laccase-DES interactions, protein engineering strategies for improving DES compatibility with laccase, and controlling the product selectivity of lignin degradation by laccase or in DES systems are extensively provided. Lastly, the challenges and prospects of the alliance between DES and laccase for lignin depolymerization are discussed. The collaboration of laccase and DES provides a great opportunity to develop an enzymatic route for lignin depolymerization.

Process intensification strategies for green solvent mediated biomass pretreatment

Demonstrated to be highly effective for lignocellulosic biomass pretreatment, deep eutectic solvent (DES) has attracted increasing attention owing to its advantages of simple synthesis, relatively low chemical cost, and better biocompatibility as compared to certain ionic liquids. Here we provide a critical review of the status of the design/selection of DES for the pretreatment of biomass feedstocks with an emphasis on the process intensification strategies: 1) integration of microwave, ultrasound, and high solid extrusion for pretreating biomass, 2) one-pot DES pretreatment, enzymatic hydrolysis, and fermentation, 3) strategies for DES recycling and product recovery; and 4) recent progress on molecular simulations toward understanding the interactions between DES and biomass compounds such as lignin and cellulose. Lastly, we provide perspectives toward cost-effective, continuous, high-solid, environmental-benign, and industrial-relevant applications and point to future research directions to address the challenges associated with DES pretreatment.

High value valorization of lignin as environmental benign antimicrobial

Lignin is a natural aromatic polymer of p-hydroxyphenylpropanoids with various biological activities. Noticeably, plants have made use of lignin as biocides to defend themselves from pathogen microbial invasions. Thus, the use of isolated lignin as environmentally benign antimicrobial is believed to be a promising high value approach for lignin valorization. On the other hand, as green and sustainable product of plant photosynthesis, lignin should be beneficial to reduce the carbon footprint of antimicrobial industry. There have been many reports that make use of lignin to prepare antimicrobials for different applications. However, lignin is highly heterogeneous polymers different in their monomers, linkages, molecular weight, and functional groups. The structure and property relationship, and the mechanism of action of lignin as antimicrobial remains ambiguous. To show light on these issues, we reviewed the publications on lignin chemistry, antimicrobial activity of lignin models and isolated lignin and associated mechanism of actions, approaches in synthesis of lignin with improved antimicrobial activity, and the applications of lignin as antimicrobial in different fields. Hopefully, this review will help and inspire researchers in the preparation of lignin antimicrobial for their applications.

A novel ternary deep eutectic solvent pretreatment for the efficient separation and conversion of high-quality gutta-percha, value-added lignin and monosaccharide from Eucommia ulmoides seed shells

A novel ternary deep eutectic solvent (DES), consisted of choline chloride, oxalic acid and ethylene glycol, was developed as a green, low-cost and recyclable pretreatment system for multi-stage utilization of Eucommia ulmoides seed shells. Under optimum conditions, 79.7 % hemicellulose and 65.6 % lignin were quickly removed while 84.0 % cellulose was retained. After DES pretreatment, the yield and purity of gutta-percha achieved 85.1 mg/g and 96.2 %, which increased 1.4 and 1.8 folds higher than that of un-treatment ones. Meanwhile, 69.1 % enzymatic digestibility of cellulose was obtained, that was 2.3 folds higher than that of raw substrates. Moreover, 53.6 % low-condensation lignin with aromatic structures and valuable aryl-ether linkages was well collected. Importantly, the DES that has been recycled five runs can still remove 73.9 % hemicellulose and 58.0 % lignin. Overall, the DES was determined to efficiently promote the separation and conversion of high-quality gutta-percha, value-added lignin and high-yield glucose from Eucommia ulmoides seed shells.

Effective fractionation of lignocellulose components and lignin valorization by combination of deep eutectic solvent with ethanol

Introduction: A combination of deep eutectic solvent with ethanol was developed for pretreatment of Broussonetia papyrifera to effectively extract lignin and promote the subsequent enzymatic hydrolysis. Methods: In order to further explore the optimal conditions for enzymatic hydrolysis, a central composite design method was applied. Results and Discussion: The correlation between each factor and glucose yield was obtained, and the optimal conditions was 160°C, 60 min, the ratio of DES to E was 1/1 (mol/mol). The results showed that compared with control, the glucose yield increased by 130.67% under the optimal pretreatment conditions. Furthermore, the specific surface area of biomass was increased by 66.95%, and the content of xylan and lignin was decreased by 86.71% and 85.83%. The correlation between xylan/lignin removal and enzymatic hydrolysis showed that the removal of lignin facilitated the glucose yield more significantly than that of xylan. To further explore the lignin valorization, the structural and antioxidant analysis of recovered lignin revealed that high temperature was favorable for lignin with good antioxidant performance. This pretreatment is a promising method for separating lignin with high antioxidant activity and improving cellulose digestibility.

One-Pot Protolignin Extraction by Targeted Unlocking Lignin-Carbohydrate Esters via Nucleophilic Addition-Elimination Strategy

Protolignin extraction can facilitate structure elucidation and valorization of lignin in biorefinery, but is rather challenging due to the complex chemical bonds present. Here, we developed the in situ generated NH₃-reline (IGNR) system to realize one-pot protolignin extraction from lignocellulose. In the IGNR system, reline consisting of choline chloride and urea acted as both a solvent and a nucleophile generator, and the nucleophilic addition-elimination mechanism was verified by model compound studies. The in situ generated NH₃ could precisely cleave the lignin-carbohydrate esters in lignocellulose with a near-quantitative retention of carbohydrates. The extracted IGNR-Protolignin exhibited native lignin substructure with high molecular weight and high β-O-4' content (41.5 per 100 aromatic units). In addition, the up-scaled kilogram reaction demonstrated the feasibility of the IGNR system for potential industrial application in a green and sustainable pathway. This work represents a breakthrough toward protolignin extraction in practice with the future goal of achieving total biorefinery.

Mild pretreatment with Brønsted acidic deep eutectic solvents for fractionating β-O-4 linkage-rich lignin with high sunscreen performance and evaluation of enzymatic saccharification synergism

Herein, a mild fractionation method by employing polyol-based Brønsted acidic DESs (BDESs) was proposed to extract lignin with well-preserved β-O-4 substructures and to enhance fermentable sugar yields simultaneously. For ethylene glycol-oxalic acid (EG-OA), more than 53 % of lignin was obtained and superb carbohydrate digestibility (i.e., glucose and xylose yields were reached to 94.6 % and 87.7 %, respectively) was achieved after pretreatment. Remarkably, detailed structural studies revealed that the polyol was incorporated into lignin, which stabilized reactive carbocation intermediates formed during BDESs treatment and prevented undesired recondensation reactions. This lignin protection mechanism was shown to play a key role in enzymatic hydrolysis enhancement and lignin valorization. The resultant β-O-4 linkage-rich lignin fractions were attractive for natural sunscreen applications due to their lighter color and excellent UV-blocking performance. Overall, this work proposed a sustainable and economically practical lignin-first biorefinery approach that is beneficial for achieving comprehensive valorization of lignocellulose.

Pretreatment of Wheat Straw Lignocelluloses by Deep Eutectic Solvent for Lignin Extraction

In order to increase the fractionation efficiency of the wheat straw, a deep eutectic solvent (DES) system consisting of chlorine/lactic acid was used in this study for wheat straw pretreatment. The outcomes exhibited that DES pretreatment significantly enhanced the capability to extract lignin, retain cellulose, and remove hemicellulose. The best condition for the pretreatment of wheat straw was 150 °C for 6 h. The process retained most cellulose in the pretreated biomass (49.94-73.60%), and the enzymatic digestibility of the pretreatment residue reached 89.98%. Further characterization of lignin showed that the high yield (81.54%) and the high purity (91.33%) resulted from the ether bond cleavage in lignin and the connection between hemicellulose and lignin. As for application, the enzymatic hydrolysis of the best condition reached 89.98%, and the lignin also had suitable stability. The investigation exhibited that DES pretreatment has the potential to realize an efficient fractionation of lignocellulosic biomass into high-applicability cellulose and lignin of high-quality.

Mechanism study of ternary deep eutectic solvents with protonic acid for lignin fractionation

This paper investigated the fractionation of lignin by ternary DES of different polyols using simulation calculation. ChCl-EG-PTSA showed the highest degradability of lignin with the absolute value of total interaction energy of -8023.80 kJ/mol, and the total number of hydrogen bonds was 91.4. The highest degradability was observed for ChCl:EG: PTSA = 2:4:1. The results show that CL^- plays a dominant role in lignin fractionation and readily forms hydrogen bonds with γ-OH. The difference is that the polyol preferred to form hydrogen bonds with α-OH in lignin. The addition of PTSA provided protons to the original system. It formed a new π-π stacking interaction with the lignin benzene ring, which destroyed the π-π stacking interaction between the original lignin. And increased the interaction of DES on lignin from -39.73 kcal/mol to -58.15 kcal/mol based on DFT.

Low-condensed lignin and high-purity cellulose production from poplar by synergistic deep eutectic solvent-hydrogenolysis pretreatment

This paper presented a green and environmentally friendly method to obtain lignin with a structure similar to milled wood lignin (MWL) and high-purity cellulose from biomass in a two-step process. The first step, maleic acid (MA), choline chloride (ChCl), and ethylene glycol (EG) ternary deep eutectic solvent (DES) pretreatment was performed to obtain lignin with less-condensed structure. The results showed that the obtained lignin had similar properties to MWL under the condition (MA/ChCl/EG = 1:5:15, 80°C, 10 h). The DES recovered still had good cycle performance. The second step, the cellulose-rich residue was hydrogenated with isopropanol-water solvent and Raney nickel to obtain high-purity cellulose. The results showed that the purity of cellulose obtained by catalytic hydrogenolysis was > 94%. The glucose yield after enzymatic hydrolysis was 243.72 mg/g, which was 14.7 times higher than the untreated poplar. Overall, this work was of great significance for the effective separation of biomass.

Successive organic solvent fractionation and homogenization of technical lignin for polyurethane foam with high mechanical performance

This work demonstrates an organic solvent fractionation method for lignin homogenization, which can effectively reduce the lignin heterogeneity and use each lignin fraction to prepare polyurethane foams (PUFs) with excellent mechanical properties. Such fractions were fully characterized by GPC, NMR (³¹P, 2D-HSQC), FTIR, and TG to obtain a detailed description of the structures and properties. The properties of PUFs from each lignin fraction showed higher compatibility than that from unfractionated industrial lignin, as studied by morphology and DSC analysis. The improvement of compatibility between the fractionated lignin fractions and polyethylene glycol can effectively enhance the mechanical properties of the prepared PUFs. The hysteresis loss (43.10%-51.85%) and resilience (95.81%-98.81%) of the fractionated lignin polyurethane foams (LPUFs) were better than that from the unfractionated LPUFs (hysteresis loss 41.64%, resilience 94.67%) at the lignin content of 5%. Subsequently, the strong relationships between lignin structures and PUF properties were demonstrated in detail. The suggested approach provides greater possibilities to prepare LPUFs with tunable properties based on real industrial lignin fractions, rather than modified lignin.

Enabling dual valorization of lignocellulose by fluorescent lignin carbon dots and biochar-supported persulfate activation: Towards waste-treats-pollutant

The rationally-designed lignocellulose valorization that promotes a novel "waste-treats-pollutant" standpoint is highly desired yet still challenging for the spread of biomass industry. At this point, a cascade technique with the assistance of deep eutectic solvent (DES) fractionation is tailored to dually valorize wheat straw into fluorescent lignin carbon dots (LCDs) and bimetallic Mg-Fe oxide-decorated biochar (MBC) via solvothermal engineering and co-precipitation/pyrolysis respectively. Benefitting from the abundance of β-aryl ether and hydroxyl groups in DES-extracted lignin, the photoluminescence LCDs emit blue color in a wide excitation span, which can be adopted to selectively detect ferric ions (Fe³⁺) in a broad dosage scale with a highly linear correlation of 10-50 μM. Taking advantages of the MBC-aided persulfate activation, we propose the efficient arbidol removal system with a universal concentration of 20-200 ppm in the scalable pH ranging from 3 to 11. The dominate migration pathways involving with active oxygen species and surface electron transfer are comprehensively studied via electron paramagnetic resonance, radical-quenching experiments, and theoretical arithmetic. With the endeavor of biorefineries, this full-scale platform ignites the dazzling wildfire from dual lignocellulose valorization that will also seek its accurate position in the kingdoms of functional materials and wastewater restoration.

Hydrogenation of Xylose to Xylitol in the Presence of Bimetallic Nanoparticles Ni3Fe Catalyst in the Presence of Choline Chloride

Hydrogenation of sugars to sugars alcohols is of prime interest for food applications for instance. Xylose obtained from the hemicellulose fraction of lignocellulosic biomass can be hydrogenated to xylitol. Herein, we conducted catalytic hydrogenation reactions in a non-conventional media approach by using choline chloride, a non-toxic naturally occurring organic compound that can form a deep eutectic solvent with xylose. Acknowledging the benefits of cost-effective transition metal-based alloys, Ni3Fe1 bimetallic nanoparticles were utilized as a hetero-catalyst. Under optimized reaction conditions (110 °C, 3 h and 30 bar H2), a highly concentrated feed of xylose (76 wt.%) was converted to 80% of xylitol, showing the benefit of using choline chloride. Overall, the catalytic conversion activity and the product selectivity in the substrate-assisted DES media are relatively high but, the recyclability of the catalyst should be improved in the presence of such media.

Polymerizable Deep Eutectic Solvent-Based Skin-Like Elastomers with Dynamic Schemochrome and Self-Healing Ability

Animal skin is a huge source of inspiration when it comes to multifunctional sensing materials. Bioinspired sensors integrated with the intriguing performance of skin-like steady wide-range strain detection, real-time dynamic visual cues, and self-healing ability hold great promise for next-generation electronic skin materials. Here, inspired by the skins of a chameleon, cellulose nanocrystals (CNCs) liquid crystal skeleton is embedded into polymerizable deep eutectic solvent (PDES) via in situ polymerization to develop a skin-like elastomer. Benefiting from the elastic ionic conductive PDES matrix and dynamic interfacial hydrogen bonding, this strategy has broken through the limitations that CNCs-based cholesteric structure is fragile and its helical pitch is non-adjustable, endowing the resulting elastomer with strain-induced wide-range (0-500%) dynamic structural colors and excellent self-healing ability (78.9-90.7%). Furthermore, the resulting materials exhibit high stretch-ability (1163.7%), strain-sensing and self-adhesive abilities, which make them well-suitable for developing widely applicable and highly reliable flexible sensors. The proposed approach of constructing biomimetic skin-like materials with wide-range dynamic schemochrome is expected to extend new possibilities in diverse applications including anti-counterfeit labels, soft foldable displays, and wearable optical devices.

Deep eutectic solvents composed of bio-phenol-derived superbase ionic liquids and ethylene glycol for CO2 capture

Deep eutectic solvents (DESs) formed by bio-phenol-derived superbase ionic liquids (ILs) and ethylene glycol (EG) exhibit a high CO₂ capacity, up to 1.0 mol CO₂/mol DESs, which is much better than those of the parent ILs. Surprisingly, mechanism results indicate that CO₂ reacts with EG, but doesn't react with phenolic anions in the solvent, which is different from other DESs formed by superbase ILs and EG. The reaction pathway between CO₂ and DESs used in this work may include two steps. The first step is the acid-base reaction between the phenolic anion and EG, which forms HO-CH₂-CH₂-O^-, and then CO₂ is attached to the anion HO-CH₂-CH₂-O^- to form a carbonate species.

Lignin condensation inhibition and antioxidant activity improvement in a reductive ternary DES fractionation microenvironment by thiourea dioxide self-decomposition

Deep eutectic solvents (DESs) as promising green solvents can efficiently remove the lignin component in lignocellulosic biomass.