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Concerns about food safety and environmental impact from chemical surfactants have prompted interest in natural lignocellulosic materials as alternatives. In this study, we combined hydrated deep eutectic solvent (DES) pretreatment with ultrasound treatment to prepare lignocellulosic nanofibrils (LCNF) from bamboo shoot shells with appropriate surface properties for stabilizing Pickering emulsions. The pretreatment intensity effectively modulated the surface characteristics of LCNF, achieving desirable wettability through lignin retention and in-situ esterification. The resulting LCNF/curcumin Pickering emulsion (CPE) demonstrated curcumin protection and pH-responsive color changes, while the ensuing CPE/PVA composite film exhibited ultraviolet shielding, mechanical strength, oxygen barrier, and antioxidant properties. Furthermore, the CPE/PVA film showed promise as a real-time indicator for monitoring shrimp freshness, maintaining sensitivity to spoilage even after six months of storage. These findings advance the advancement of green LCNF technologies, providing eco-friendly solutions for valorizing bamboo shoot shells and enhancing the application of LCNF in Pickering emulsions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Deep eutectic solvents (DES) are renowned for their effectiveness in deconstructing lignocellulose and extracting lignin, yet the challenges lie in lignin condensation and the disposal of the DES remnants after pretreatment. To overcome these issues, this work proposed a holistic strategy utilizing deep eutectic solvent (DES)-driven lignocellulose deconstruction to upgrade lignocellulose into nitrogen-doped carbon dots (CDs) and iron-decorated porous carbons, serving as photocatalysts and adsorbents, respectively. These nitrogen-doped CDs via the choline chloride/FeCl 3 DES pretreatment exhibited abundant nitrogen/oxygen functional groups, enhancing photocatalytic activities and facilitating effective charge separation and transfer. The photocatalytic efficiency of the CDs on dyes reached 97 % under acidic conditions primarily, and free radical quenching experiments indicated that singlet oxygen was the dominant oxidant species. Moreover, the adsorption capabilities of Fe-decorated porous carbons for Congo red reached 2432.3 mg·g -1 , surpassing most existing carbon materials. The adsorption mechanism was due to a synergistic effect including physical adsorption, coordination, hydrogen bonding, electrostatic, and π-π interactions. This study proposed a synergetic conversion of DES and lignocellulose into functional carbon materials for wastewater remediation, which inspired the development of a green and cost-effective biorefinery., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

In recent years, nanocellulose (NC) has gained significant attention due to its remarkable properties, such as adjustable surface chemistry, extraordinary biological properties, low toxicity and low density. This review summarizes the preparation of NC derived from lignocellulosic biomass (LCB), including cellulose nanofibrils (CNF), cellulose nanocrystals (CNC), and lignin-containing cellulose nanofibrils (LCNF). It focuses on examining the impact of non-cellulosic components such as lignin and hemicellulose on the functionality of NC. Additionally, various surface modification strategies of NC were discussed, including esterification, etherification and silylation. The review also emphasizes the progress of NC application in areas such as Pickering emulsions, food packaging materials, food additives, and hydrogels. Finally, the prospects for producing NC from LCB and its application in food-related fields are examined. This work aims to demonstrate the effective benefits of preparing NC from lignocellulosic biomass and its potential application in the food industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The practical applications of lithium-sulfur (Li-S) batteries have severely been hindered by notorious shuttle effect and sluggish redox kinetics of lithium polysulfide intermediates (LiPSs), which bring about rapid capacity degradation, low coulombic efficiency and poor cycling stability. In this work, 1T-rich MoS 2 nanosheets are in-situ developed onto the conductive porous carbon matrix (1T-rich MoS 2 @PC) as efficient polysulfide promotors for high-performance Li-S batteries. The porous carbon skeleton tightly anchors MoS 2 nanosheets to prevent their reaggregation and ensures accessible electrical channels, and at the same time provides a favorable confined space that promotes the generation of 1T-rich MoS 2 structure. More importantly, the uniformly distributed metallic 1T-rich MoS 2 nanosheets not only affords rich sulfphilic sites and high binding energy for immobilizing LiPSs, but also favors rapid electron transfer and LiPSs conversation kinetics, substantially regulating sulfur chemistry in working cells. Consequently, the Li-S cell assembled with 1T-rich MoS 2 @PC modified separator delivers a remarkable cycling stability with ultralow capacity decay rate of 0.067% over 500 cycles at 1C. Encouragingly, under harsh conditions (high sulfur loading of 4.78 mg cm -2 and low E/S ratio of 8 μL mg -1 ), a favorable electrochemical performance can still be demonstrated. This study highlights the profitable design of 1T-rich MoS 2 /carbon based electrocatalyst for suppressing shuttle effect and promoting catalytic conversation of LiPSs, and has the potential to be applied to in other energy storage systems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Understanding and recognizing the structural characteristics of lignin-carbohydrate complexes (LCCs) and lignin in different growth stages and tissue types of bamboo will facilitate industrial processes and practical applications of bamboo biomass. Herein, the LCC and lignin samples were sequentially isolated from fibers and parenchyma cells of bamboo with different growth ages. The diverse yields of sequential fractions not only reflect the different biomass recalcitrance between bamboo fibers and parenchyma cells but also uncover the structural heterogeneity of these tissues at different growth stages. The molecular structures and structural inhomogeneities of the isolated lignin and LCC samples were comprehensively investigated. The results showed that the structural features of lignin and LCC linkages in parenchyma cells were abundant in β- O -4 linkages but less with carbon-carbon linkages, suggesting that lignin and cross-linked LCC in parenchyma cells are simple in nature and easily to be tamed and tractable in the current biorefinery. Parallelly, the different ball-milled samples were directly characterized by high-resolution (800 M) solution-state 2D-HSQC NMR to analyze the whole lignocellulosic material. Overall, the scheme presented in this study will provide a comprehensive understanding of lignin and LCC linkages in fibers and parenchyma cells of bamboo and enable the utilization of bamboo biomass.

Utilizing renewable lignocellulosic resources for wastewater remediation is crucial to achieving sustainable social development. However, the resulting by-products and the synthetic process characterized by complexity, high cost, and environmental pollution limit the further development of lignocellulose-based materials. Here, we developed a sustainable strategy that involved a new functional deep eutectic solvent (DES) to deconstruct industrial xylose residue into cellulose-rich residue with carboxyl groups, lignin with carboxyl and quaternary ammonium salt groups, and DES effluent rich in lignin fragments. Subsequently, these fractions equipped with customized functionality were used to produce efficient wastewater remediation materials in cost-effective and environmentally sound manners, namely, photocatalyst prepared by carboxyl-modified cellulose residue, biochar-based adsorbent originated from modified lignin, and flocculant synthesized by self-catalytic in situ copolymerization of residual DES effluent at room temperature. Under the no-waste principle, this strategy upgraded the whole components of waste lignocellulose into high-value-added wastewater remediation materials with excellent universality. These materials in coordination with each other can stepwise purify high-hazardous mineral processing wastewater into drinkable water, including the removal of 99.81% of suspended solids, almost all various heavy metal ions, and 97.09% chemical oxygen demand, respectively. This work provided promising solutions and blueprints for lignocellulosic resources to alleviate water shortages while also advancing the global goal of carbon neutrality., Competing Interests: Competing interests: T.-Q.Y., X.S., and B.W. are the inventors on a patent application submitted by Beijing Forestry University that covers the current method for preparing flocculants from DES residues. The authors declare that they have no other competing interests., (Copyright © 2024 Bin Wang et al.)

Blending poly (butylene adipate-co-terephthalate) (PBAT) and polylactic acid (PLA) is a cost-effective strategy to obtain biodegradable plastic with complementary properties. However, the incompatibility between PBAT and PLA is a great challenge for fabricating high-performance composite films. Herein, the ethyl acetate fractionated lignin with the small glass transition temperature and low molecular weight was achieved and incorporated into the PBAT/PLA composite as a compatibilizer. The fractionated lignin can be uniformly dispersed within the PBAT/PLA matrix through a melt blending process and interact with the molecular chain of PBAT and PLA as a bonding bridge, which enhances the intermolecular interactions and reduces the interfacial tension of PBAT/PLA. By adding fractionated lignin, the tensile strength of the PBAT/PLA composite increased by 35.4 % and the yield strength increased by 37.7 %. Owing to lignin, the composite films possessed the ultraviolet shielding function and exhibited better water vapor barrier properties (1.73 ± 0.08 × 10 -13  g·cm/cm 2 ·s·Pa). This work conclusively demonstrated that fractionated lignin can be used as a green compatibilizer and a low-cost functional filler for PBAT/PLA materials, and provides guidance for the application of lignin in biodegradable plastics., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Deep eutectic solvents (DESs) have emerged as promising and eco-friendly solvents for the efficient extraction of lignin from biomass due to their low cost and environmental benefits. Nevertheless, the prevalent use of acidic DESs in lignin extraction often results in excessive depolymerization and recondensation of lignin, thereby impeding its downstream applications. In this study, we developed a range of alkaline DESs (ADESs), both pure and peroxide-containing, for the extraction of high-quality lignin from bamboo. Moreover, carbon dioxide (CO 2 ) was employed for the precipitation and regeneration of the extracted lignin. The obtained lignin fractions were comprehensively characterized in terms of yield, purity, morphology, solubility, structural features, and anti-UV/oxidant activity. The results showed that the monoethanolamine-based ADES demonstrated superior performance among the pure ADESs. Structural analysis confirmed the well-preserved substructures of lignin fractions obtained using ADESs, with β-O-4 bond retention ranging from 49.8 % to 68.4 %. The incorporation of a suitable amount of peroxide improved lignin yield, morphology, solubility, and anti-UV/oxidant activity. Additionally, the anti-UV/oxidant activity of lignin exhibited a positive correlation with its phenolic hydroxyl content. This study provides a valuable reference for the green and sustainable production and valorization of lignin within the existing biorefinery framework., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Effective separation of lignin macromolecules from the xylose pre-hydrolysates (XPH) during the xylose production, thus optimizing the separation and purification process of xylose, is of great significance for reducing the production costs, achieving the high value-added utilization of lignin and increasing the industrial revenue. In this study, a simple and robust method (pH adjustment) for the separation of lignin from XPH was proposed and systematically compared with the conventional acid-promoted lignin precipitation method. The results showed that the lignin removal ratio (up to 60.34 %) of this simple method was higher than that of the conventional method, and the proposed method eliminated the necessity of heating and specialized equipment, which greatly reduced the separation cost. Meanwhile, this simple method does not destroy the components in XPH (especially xylose), ensuring the yield of the target product. On the other hand, the obtained lignin was nano-scale with less condensed structures, which also possessed small molecular weights with narrow distribution, excellent antioxidant activity (8-14 times higher than commercial antioxidants) and UV protection properties. In conclusion, the proposed simple separation method could effectively separate lignin from XPH at low cost, and the obtained lignin had potential commercial applications, which would further enhance the overall profitability of industrial production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

In this study, light-colored lignin was extracted from bamboo shoot shells (BSS) using a hydrated deep eutectic solvent (DES) pretreatment. The hydrated DES used in pretreatment consist of formic acid, benzyl triethylammonium chloride (BTEAC) and water. The pretreatment using a hydrated DES containing 30% water (H30) demonstrate efficient delignification (82.9%). Additionally, the hydrated DES protected the β-O-4 linkage from excessive cleavage and recondensation as well as keep the light-colored of lignin. Moreover, the hydrated DES extracted lignin exhibits superior antioxidant performance and tyrosinase inhibitory capacity compared to the control. Notably, incorporating 5% lignin of H30-extracted lignin into a commercial suncream led to a remarkable enhancement of the SPF value, elevating from 14.8 to 32.6. In summary, the proposed hydrated DES pretreatment method offers significant benefits for extracting light-colored lignin, thereby promoting the multifunctional application of lignin in cosmetics., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

In this work, a green and robust pretreatment which integrated acetic acid-catalyzed hydrothermal and wet mechanical pretreatment, was developed to efficiently produce high yield (up to 40.12%) of xylooligosaccharides and digestible substrates from Caffeoyl Shikimate Esterase down-regulated and control poplar wood. Subsequently, superhigh yield (more than 95%) of glucose and residual lignin were obtained after a moderate enzymatic hydrolysis. The residual lignin fraction exhibited a well-preserved β-O-4 linkages (42.06/100Ar) and high S/G ratio (6.42). Subsequently, lignin-derived porous carbon was successfully synthesized, and it exhibited a high specific capacitance of 273.8 F g -1 at 1.0 A g -1 and long cycling stability (remained 98.5% after 10,000 cycles at 5.0 A g -1 ) compared to control poplar wood, demonstrating that special advantage of this genetically-modified poplar in this integrated process. This work developed an energy-saving and eco-friendly pretreatment technology as a waste-free route for converting different lignocellulosic biomass to multiple products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Okadaic acid (OA) is one of the most prevalent marine phycotoxin with complex toxicity, which can lead to toxic symptoms such as diarrhea, vomiting, nausea, abdominal pain, and gastrointestinal discomfort. Studies have shown that the main affected tissue of OA is digestive tract. However, its toxic mechanism is not yet fully understood. In this study, we investigated the changes that occurred in the epithelial microenvironment following OA exposure, including the epithelial barrier and gut bacteria. We found that impaired epithelial cell junctions, mucus layer destruction, cytoskeletal remodeling, and increased bacterial invasion occurred in colon of rats after OA exposure. At the same time, the gut bacteria decreased in the abundance of beneficial bacteria and increased in the abundance of pathogenic bacteria, and there was a significant negative correlation between the abundance of pathogenic bacteria represented by Escherichia/Shigella and animal body weight. Metagenomic analysis inferred that Escherichia coli and Shigella spp. in Escherichia/Shigella may be involved in the process of cytoskeletal remodeling and mucosal layer damage caused by OA. Although more evidence is needed, our results suggest that opportunistic pathogens may be involved in the complex toxicity of OA during OA-induced epithelial barrier damage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

In this work, a rapid one-pot hydrated deep eutectic solvent (DES) pretreatment was proposed to facilitate the conversion of carbohydrates from lignocellulosic biomass to monosaccharides. Specifically, the pure and hydrated DES based on benzyl triethylammonium chloride (BTEAC), formic acid (FA) and water was used to pretreat bamboo shoot shells (BSS) by microwave heating. The pretreated solid residues were enzymatically saccharified to produce fermentable sugars, and the hydrolyzed carbohydrates and lignin remained in the hydrolyzate. The results showed that the yield of monosaccharides from the hydrated DES hydrolyzate (193.7-228.4 g/kg) was significantly higher than that (45.9-66.1 g/kg) of pure DES. The 30% hydrated DES pretreatment achieved the best glucose yield (89.03%) and a total monosaccharides yield of 555.4 g/kg, which corresponded to a conversion ratio of carbohydrates to monosaccharides of 87.0%. The proposed process is a robust method for the efficiently convert carbohydrates from BSS into monosaccharides., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Utilizing starch, an abundant polysaccharide, as the renewable filler to blend with poly(butylene adipate-co-terephthalate) (PBAT) is a feasible tactic to construct cost-effective and high-performance biodegradable materials. It's worth noting that the thermal processing properties of starch can be manipulated by its plasticized behavior. Herein, epoxidized soybean oil (ESO) and glycerol were used as the plasticizer for native corn starch and the plasticized starch was integrated with PBAT to manufacture starch-based biodegradable blend films. ESO breaks the hydrogen bonds between starch chains through the fatty chains grafting reaction and increases the distance between starch molecular chains due to the large molecular weight of ESO. Meanwhile, glycerol molecules are incorporated into the starch molecular chains, and fatty chains grafted starch chains, effectively reducing the intermolecular forces of molecular chains. On account of the synergistic plasticization of ESO and glycerol which possess good compatibility with PBAT, the PS G20E10 blend film achieved a tensile strength, an elongation at break of 16.11 MPa and 612.09 %, and the balanced water and oxygen permeability properties., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2023. Published by Elsevier B.V.)

Phytoremediation with energy crops is considered an integrated technology that provides both environment and energy benefits. Herein, the sweet sorghum cultivated on Cd-contaminated farmland (1.21 mg/kg of Cd in the soil) showed promising phytoremediation potential, and the approach for utilizing sorghum stalks was explored. Sweet sorghum bagasse with Cd contamination was pretreated with dilute acid in order to improve enzymatic saccharification and achieve Cd recovery, resulting in harmless and value-added utilization. After pretreatment, hemicelluloses were dramatically degraded, and the lignocellulosic structures were partially deconstructed with xylan removal up to 98.1%. Under the optimal condition (0.75% H 2 SO 4 ), the highest total sugar yield was 0.48 g/g of raw bagasse; and nearly 98% of Cd was enriched in the liquid phase. Compared with normal biomass, Cd reduced the biomass recalcitrance and further facilitated the deconstruction of biomass under super dilute acid conditions. This work provided an example for the subsequent valorization of Cd-containing biomass and Cd recovery, which will greatly facilitate the development of phytoremediation of heavy metal contaminated soil., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

To comprehend the biosynthesis processes of conifers, it is essential to investigate the disparity between the cell wall shape and the interior chemical structures of polymers throughout the development of Chinese pine. In this study, branches of mature Chinese pine were separated according to their growth time (2, 4, 6, 8 and 10 years). The variation of cell wall morphology and lignin distribution was comprehensively monitored by scanning electron microscopy (SEM) and confocal Raman microscopy (CRM), respectively. Moreover, the chemical structures of lignin and alkali-extracted hemicelluloses were extensively characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The thickness of latewood cell walls increased steadily from 1.29 μm to 3.38 μm, and the structure of the cell wall components became more complicated as the growth time increased. Based on the structural analysis, it was found that the content of β-O-4 (39.88-45.44/100 Ar), β-β (3.20-10.02/100 Ar) and β-5 (8.09-15.35/100 Ar) linkages as well as the degree of polymerization of lignin increased with the growth time. The complication propensity increased significantly over 6 years before slowing to a trickle over 8 and 10 years. Furthermore, alkali-extracted hemicelluloses of Chinese pine mainly consist of galactoglucomannans and arabinoglucuronxylan, in which the relative content of galactoglucomannans increased with the growth of the pine, especially from 6 to 10 years., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Deep eutectic solvents (DESs) have unique advantages in biomass conversion. However, the migration and transformation mechanism of lignin in the cell wall during the DES pretreatment is still elusive. In this work, Eucalyptus blocks were pretreated in choline chloride/lactic acid DES to reveal the lignin migration. Meanwhile, the remaining lignin in the pretreated residue, the regenerated DES lignin, and the solubilized degraded lignin in the recovered DES were investigated to decipher the lignin transformation. Results showed that the DES pretreatment resulted in the penetration of DES from the cell lumen to the cell wall, and lignin in the secondary wall was more easily dissolved than that in the cell corner middle lamella. The syringyl unit of lignin was better stabilized in the DES than the guaiacyl unit of lignin. The condensed lignin fraction mainly remained in the pretreated residue, while the solubilized degraded lignin fraction was monomeric aromatic ketone compounds. This study elucidates the fate of lignin during the DES pretreatment, which could also promote the development of a modern lignocellulosic pretreatment technique., (© 2022 Wiley-VCH GmbH.)

Complex and heterogeneous structures of lignin impede its further conversion and valorization. Herein, three technical lignins (from softwood, hardwood, and grass) were fractionated with acetone solvent to reduce their structural heterogeneity, which were then blended with poly-(butylene adipate-co-terephthalate) (PBAT) to fabricate biodegradable bio-composites. Macromolecular structures of lignins and their effects on the properties of lignin/PBAT composites were thoroughly investigated. Results showed that all fractionated lignin composites displayed better properties. Particularly, the raw and fractionated softwood lignin-based composites exhibited superior performance compared with others. Benefiting from the lower molecular weight, hydroxyl groups, and condensation, acetone fractionated softwood lignin presented the lowest T g (115.7 °C), achieving ideal melt miscibility and interfacial interaction between lignin and PBAT. The decreased T g of lignin facilitated the lignin dispersion in the matrix and increase the mechanical strength of the composites. Overall, the fractionated technical lignin possessed desirable physical and chemical structure features, conferring composites good miscibility and mechanical properties., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Understanding of the morphological changes at different growth stages and lignin accumulation pattern for pine biomass plays the key role in facilitating the further development of value-added utilization and downstream conversion processes. This work systematically revealed the morphological change and lignin accumulation pattern in Chinese pine branches cell walls via confocal Raman microscopy (CRM) technology. Meanwhile, the structural characteristics of isolated lignin samples from different growth stages were synthetically characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques. The results indicated that the content of pith in adult pine new branch was bigger than juvenile trees. With the increase of physiological age, the branches in adult pine could accumulate more lignin both in overall content and the concentration of cell corner middle layer. Moreover, the significantly increases of molecular weights and the β-O-4, β-β linkages content revealed that the lignin macromolecule of pine would polymerize faster in the adult stage (14, 35 years). The panorama generated from the structural and chemical features of pine native lignin not only benefited to understand the biosynthetic pathways and lignin macromolecules structural variation in plant cell walls from different growth stages but also contributed to the valorization and deconstruction of biomass., (Copyright © 2022. Published by Elsevier B.V.)

Bamboo processing residue, which is rich in parenchyma cells, was treated as huge waste in bamboo processing industry, such as reassemble bamboo and bamboo flooring. Herein, autohydrolysis and rapid different deep eutectic solvents (DES) delignification strategy were consecutively performed to remove hemicelluloses and lignin from bamboo processing residue. The xylooligosaccharides (XOS) with high yield (34.35%) was achieved in the autohydrolysis process. Results showed that alkaline DES pretreatment resulted in the highest glucose yield (88.22%) and relatively high delignification rate (83.75%) as well as well-preserved lignin structures. However, the lignin fractions obtained under acidic DES conditions were tending to assemble into lignin nanoparticles (LNPs) and having excellent antioxidant activity as compared to those obtained from alkaline DES system. In brief, the combination of autohydrolysis and rapid DES delignification can achieve orientated fractionation of the components from the industrialized bamboo., (Copyright © 2022. Published by Elsevier Ltd.)

An aspirational pretreatment method for efficient fractionation and tailored valorization of large industrial biomass can ensure the realizability of sustainable biorefinery strategies. In this study, an ultrafast alkaline deep eutectic solvents (DES) pretreatment strategy was developed to efficiently extract the lignin nanoparticles and retain cellulose residues that could be readily enzymatic saccharified to obtain fermentative glucose for the bioenergy production from industrial xylose residue. Results showed that the DES pretreatment had excellent delignification performance and the regenerated DES lignin nanoparticles exhibited well-preserved structures and excellent antioxidant activity, as well as low molecular weights and relatively uniform size distribution, which could facilitate downstream catalytic degradation for production of chemicals and preparation of lignin-based materials. Under the optimal condition (DES pretreatment: 80 °C, 10 min; saccharification: 10 FPU/g, 5 wt%, 100 mg/g Tween 80), the glucose yield of 90.12% could be achieved, which was dramatically increased compared to raw materials., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Developing a biorefinery process for a highly integrated valorization and fractionation of lignocellulose is crucial for its utilization. Herein, a biphasic system comprising choline chloride/lactic acid and 2-methyltetrahydrofuran with Al 2 (SO 4 ) 3 and H 2 SO 4 as catalysts was applied to pretreat Eucalyptus. Results showed that under the optimized conditions (150 °C, 30 min, 0.2 M Al 2 (SO 4 ) 3 , 0.075 M H 2 SO 4 ), the furfural yield and enzymatic hydrolysis efficiency could reach 54.7% and 97.0%, respectively. The efficient cellulose conversion was attributed to remarkable removal of lignin (91.0%) and hemicelluloses (100.0%), thereby causing the disruption of cell wall structure and enhancement of cellulose accessibility. Meanwhile, confocal Raman microscope and atomic force microscope displayed that the pretreatment resulted in the decreasing intensities of carbohydrates and lignin different regions of cell walls, and exposing of the embedded microfibers from noncellulosic polymers. Overall, the deep eutectic solvent-based biphasic system displayed high performance for effective utilization of carbohydrate components in lignocellulose., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A synergistic pretreatment that realizing effective fractionation and targeted valorization can guarantee the implementability to future biorefinery scenario. In the present study, a stepwise approach using hydrothermal and deep eutectic solvents (DES) pretreatment was developed to preferentially dissociate hemicelluloses and further remove lignin from poplar, while retaining a cellulose-rich substrate that can be easily digested via enzymatic saccharification to obtain glucose. Results showed that the hydrothermal filtrate is mainly composed of xylooligosaccharide (XOS), monosaccharides, byproducts, and xylan-type hemicelluloses, which have homogenous structures and uniform molecular weights distribution as well as excellent antioxidant activity. Subsequent DES pretreatment further removed the lignin barriers, leading to a remarkable increase in the saccharification efficiency from 15.72% to 96.33% under optimum conditions for enzymatic hydrolysis. In short, the integrated pretreatment is effective for dissociating and chemical conversion of poplar wood, which was reasonable to promote the frontier of highly available biorefinery., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Deep eutectic solvents (DES) pretreatment is a promising approach to decrease "biomass recalcitrance" and boost the cellulose bioconversion as well as lignin valorization. In this study, a short-time DES pretreatment strategy was performed to enhance the production of high-yield fermentable sugars and tailored lignin nanoparticles (LNPs) from abaca. The glucose yield reached 92.4% under the optimal pretreatment condition (110 °C, 30 min), which was dramatically increased in comparison with that (9.5%) of control abaca. Simultaneously, nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques indicated that the removed and regenerated DES lignin fractions displayed depolymerized structures and have relatively low molecular weight with relatively homogeneous morphology and narrow size distribution. Transmission electron microscope (TEM) analysis indicated that these lignin fractions are LNPs and the size of the optimal LNPs fraction is ranged from 30 nm to 50 nm. Moreover, all the DES lignin exhibited excellent antioxidant activities as compared to the commercial antioxidant butylated hydroxytoluene (BHT), which can be used as a promising natural antioxidant in industry. In short, this study demonstrated that the short-time DES pretreatment will improve the enzymatic digestibility and facilitate the controllable production and valorization of LNPs from abaca biomass, which will further promote the economic and overall benefits of biorefinery., (Copyright © 2021. Published by Elsevier B.V.)

In recent years, visualization and characterization of lignocellulose at different scales elucidate the modifications of its ultrastructural and chemical features during hydrothermal pretreatment which include degradation and dissolving of hemicelluloses, swelling and partial hydrolysis of cellulose, melting and redepositing a part of lignin in the surface. As a result, cell walls are swollen, deformed and de-laminated from the adjacent layer, lead to a range of revealed droplets that appear on and within cell walls. Moreover, the certain extent morphological changes significantly promote the downstream processing steps, especially for enzymatic hydrolysis and anaerobic fermentation to bioethanol by increasing the contact area with enzymes. However, the formation of pseudo-lignin hinders the accessibility of cellulase to cellulose, which decreases the efficiency of enzymatic hydrolysis. This review is intended to bridge the gap between the microstructure studies and value-added applications of lignocellulose while inspiring more research prospects to enhance the hydrothermal pretreatment process., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Herein, a two-step hydrothermal pretreatment combined with alkali extraction method was applied to deconstruct the poplar cell walls for enzymatic hydrolysis. Results revealed that 88.1 % of hemicelluloses and 77.6 % of lignin were removed during the integrated treatment performed at 180 °C and a maximum enzymatic hydrolysis efficiency of 96.1 % was achieved. Confocal Raman microscopy suggested that the removal of hemicelluloses from cell walls was inhomogeneous, and most hemicelluloses were released from the secondary wall. In addition, 35.2-56.8 % of hemicelluloses were isolated from the integrated treatment. Detailed structural analysis revealed that the water-soluble hemicelluloses possessed more branched structure than the alkali-soluble hemicelluloses and the hemicelluloses isolated from the poplar were mainly composed of a linear backbone of (1→4)-β-d-Xylp with 4-O-Me-α-d-GlcpA attached as side chains. This work provides an efficient pathway to transform poplar into fermentable sugars and hemicelluloses with considerable yield., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The lignin-first strategy has emerged as one of the most powerful approaches for generating novel platform chemicals from lignin by efficient depolymerization of native lignin. Because of the emergence of this novel depolymerization method and the definition of viable platform chemicals, future focus will soon shift towards innovative downstream processing strategies. Very recently, many interesting approaches have emerged that describe the production of valuable products across the whole value chain, including bulk and fine chemical building blocks, and several concrete examples have been developed for the production of polymers, pharmaceutically relevant compounds, or fuels. This Minireview provides an overview of these recent advances. After a short summary of catalytic systems for obtaining aromatic monomers, a comprehensive discussion on their separation and applications is given. This Minireview will fill the gap in biorefinery between deriving high yields of lignin monomers and tapping into their potential for making valuable consumer products., (© 2020 Wiley-VCH GmbH.)

The valorization of lignin to replace phenol is significant in the production of phenolic resins. However, a great challenge is to produce lignin-based resin (LR) with a suitable viscosity and high substitution rate of lignin to phenol. In this study, LRs were produced using hardwood technical lignin derived from the pulping industry. Structural analysis of the LRs indicated that the unsubstituted para and ortho carbon atoms of the aromatic ring influenced the curing temperature and activation energy of the resins. The curing kinetics and thermal decomposition study implied that urea and methylene groups in cured LRs were significant factors that affected the thermal stability negatively. The prepared LRs showed desirable features if used as adhesives to make plywood. This is the first approach in which a substitution rate of up to 65 % is achieved for low-reactive-site hardwood lignin, which provides a solution to the challenge of the simultaneous realization of the high addition of lignin and the adaptive viscosity of resins., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We developed an innovative single-step pyrolysis approach that combines microwave heating and activation by CO 2 or steam to transform orange peel waste (OPW) into microwave activated biochar (MAB). This involves carbonization and activation simultaneously under an inert environment. Using CO 2 demonstrates dual functions in this approach, acting as purging gas to provide an inert environment for pyrolysis while activating highly porous MAB. This approach demonstrates rapid heating rate (15-120 °C/min), higher temperature (> 800 °C) and shorter process time (15 min) compared to conventional method using furnace (> 1 h). The MAB shows higher mass yield (31-44 wt %), high content of fixed carbon (58.6-61.2 wt %), Brunauer Emmett Teller (BET) surface area (158.5-305.1 m 2 /g), low ratio of H/C (0.3) and O/C (0.2). Activation with CO 2 produces more micropores than using steam that generates more mesopores. Steam-activated MAB records a higher adsorption efficiency (136 mg/g) compared to CO 2 activation (91 mg/g), achieving 89-93 % removal of Congo Red dye. The microwave pyrolysis coupled with steam or CO 2 activation thereby represents a promising approach to transform fruit-peel waste to microwave-activated biochar that remove hazardous dye., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Lithium-sulfur (Li-S) batteries are highly regarded as the next-generation energy-storage devices because of their ultrahigh theoretical energy density of 2600 Wh kg -1 . Sulfurized polyacrylonitrile (SPAN) is considered a promising sulfur cathode to substitute carbon/sulfur (C/S) composites to afford higher Coulombic efficiency, improved cycling stability, and potential high-energy-density Li-SPAN batteries. However, the instability of the Li-metal anode threatens the performances of Li-SPAN batteries bringing limited lifespan and safety hazards. Li-metal can react with most kinds of electrolyte to generate a protective solid electrolyte interphase (SEI), electrolyte regulation is a widely accepted strategy to protect Li-metal anodes in rechargeable batteries. Herein, the basic principles and current challenges of Li-SPAN batteries are addressed. Recent advances on electrolyte regulation towards stable Li-metal anodes in Li-SPAN batteries are summarized to suggest design strategies of solvents, lithium salts, additives, and gel electrolyte. Finally, prospects for future electrolyte design and Li anode protection in Li-SPAN batteries are discussed., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this study, the cellulose and hemicelluloses in heartwood, sapwood, and bark of E. urophylla × E. grandis were comprehensively investigated. The ultrastructural topochemistry of carbohydrates in cell walls was examined in situ by confocal Raman microscopy. Cellulose and alkali-extractable hemicelluloses samples were isolated from different tissues and comparatively characterized by compositional carbohydrate analyses, determination of molecular weights, FT-IR spectroscopy, and XRD and NMR techniques. It was found that among all of the samples, heartwood cellulose had the highest molecular weight as well as the lowest degree of crystallinity. Meanwhile the hemicelluloses in heartwood had higher xylose content, lower degree of branching, slightly lower molecular weights but narrower polydispersity than those in sapwood. The eucalyptus hemicelluloses mainly consisted of (1→4)-β- D -xylan backbone with glucuronic acid side chains. Furthermore, the hemicelluloses isolated from sapwood had a higher degree of substitution with terminal galactose than those isolated from heartwood and bark., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

To maximize the utilization of Abaca lignin in the current biorefinery, structural characteristics of native lignin from Abaca were firstly comprehensively investigated. Parallelly, effective delignification of Abaca was achieved by alkaline hydrogen peroxide (AHP) process, which facilitated the production of specialty paper in industry. The structural changes of lignin macromolecules during the AHP delignification were illustrated by comparing the structural differences of the released lignin fraction and corresponding native lignin, which were analyzed via the advanced analytical methods, such as 2D-HSQC NMR, 31 P NMR, pyrolysis-GC/MS, and GPC techniques. It was found that Abaca lignin is a HGS-type lignin, which is overwhelmingly composed of β-O-4 linkages and abundant hydroxycinnamic acids (mainly p-coumaric acid). In addition, partial cleavage of β-O-4 linkages and p-coumarate in lignin occurred during the AHP delignification process. Meanwhile, AHP process also led to the elevation of H-type lignin units in AHPL. Considering that β-O-4 bond is vulnerable in the catalytic degradation process of lignin, the lignin with abundant β-O-4 linkages is beneficial to the downstream conversion of lignin into aromatic chemicals., Competing Interests: Declaration of competing interest The authors declare no competing financial interest., (Copyright © 2018. Published by Elsevier B.V.)

Understanding the distribution and structural features of lignin in heartwood, sapwood, and bark of terrestrial plants is important to optimize the industrial utilization of lignocellulose. In this work, the lignins in heartwood, sapwood, and bark of Eucalyptus urophylla × E. grandis were comparatively studied. Confocal Raman microscopy was used to probe the heterogeneity of lignin distribution in situ. The swollen residual enzyme lignin samples were isolated and systematically characterized to determine the structural differences. The results showed that the content and molecular weights of lignin gradually decreased in the order of heartwood, sapwood, and bark. The S/G ratios of heartwood lignin (3.45) and sapwood lignin (2.74) suggested the increase of deposited S-type lignin with the maturity of wood. The bark lignin exhibited a high frequency of β-O-4' linkages and showed a unique substructural pattern with the absence of spirodienone substructures and p-hydroxycinnamyl alcohol end-groups., (Copyright © 2018. Published by Elsevier B.V.)

In the present study, lignin from eucalyptus was extracted with 80% alkaline dioxane (0.05 M NaOH) from ball-milled wood and subsequently fractionated by gradient acid precipitation from the filtrate. Meanwhile, the residual lignin was prepared by a double enzymatic hydrolysis process. The yield of the lignin extracted by alkaline dioxane (L A-2 ) was 29.5%. The carbohydrate contents and molecular weights of the gradient acid precipitated lignin fractions gradually decreased from 4.90 to 1.36% and from 7770 to 5510 g/mol, respectively, with the decline of the pH value from 6 to 2. Results from two-dimensional heteronuclear single quantum coherence nuclear magnetic resonance (NMR) and 31 P NMR spectroscopy showed an evident reduction of β- O-4 ' linkages with the pH value decrease, while the contents of aliphatic -OH, phenolic -OH, and carboxylic groups displayed an increasing trend. Moreover, the residual lignin exhibited the highest molecular weight (11690 g/mol), the most abundant β- O-4 ' linkages (71.1%), and the highest S/G ratio (4.68).

Effect of sonication on the extractability and physico-chemical properties of hemicelluloses from Eucalyptus grandis using 5% KOH solution at 50 °C for 3 h has been comparatively studied. The results showed that the yield of hemicelluloses increased from 2.6 to 19.6% as the ultrasonic time was extended from 5 to 35 min. The highest yield of hemicelluloses (95.2%) was achieved at 30 min ultrasonic time. Xylose was the dominant sugar (82.94-84.96%) of all the hemicellulosic fractions. Furthermore, the hemicelluloses obtained by ultrasound-assisted extractions had slightly lower molecular weights (74,510-66,770 g/mol) and thermal stabilities, but higher contents of xylose (83.95-84.96%). The increased yield of ultrasonically extracted hemicelluloses, which have preserved their main structural properties, confirmed the great potential of ultrasound-assisted extraction to separate hemicelluloses from Eucalyptus grandis at an industrial level., (Copyright © 2018. Published by Elsevier Ltd.)

Eco-friendly and good-performance resin adhesives are needed for wood manufacturing. In this study, phenol-urea-formaldehyde (PUF) resin adhesives were modified by adding various ratios of resorcinol. The properties of PUF, phenol-resorcinol-urea-formaldehyde (PRUF) resin adhesives, and the performances of the prepared plywood were tested. The curing behaviors and the structural features of the PUF and PRUF resin adhesives were investigated via dynamic scanning calorimetry, thermal gravimetric analysis, 13 C NMR, and cross polarization magic angle spinning 13 C NMR. The results indicated that 1.3% resorcinol (based on resin, w/w) could decrease the curing temperature and accelerate the curing process after PUF resin modification. The PRUF resin adhesives demonstrated a lower activation energy during the curing process, with up to 28.8% less energy than that of PUF resin adhesive without any curing agent. The plywood demonstrated low formaldehyde emissions (<0.1 mg L -1 ) and acceptably high bonding strengths (>1.00 MPa). This work provided a method for preparing an easy-cured and high-performance phenolic resin for wood manufacturing., Competing Interests: The authors declare no competing financial interest.

Main Conclusion: Six types of lignin-carbohydrate complex (LCC) fractions were isolated from Eucalyptus. The acidic dioxane treatment applied significantly improved the yield of LCCs. The extraction conditions had a limited impact on the LCC structures and linkages. Characterization of the lignin-carbohydrate complex (LCC) structures and linkages promises to offer insight on plant cell wall chemistry. In this case, Eucalyptus LCCs were extracted by aqueous dioxane, and then precipitated sequentially by 70% ethanol, 100% ethanol, and acidic water (pH = 2). The composition and structure of the six LCC fractions obtained by selective precipitation were investigated by sugar analysis, molecular weight determination, and 2D HSQC NMR. It was found that the acidic (0.05-M HCl) dioxane treatment significantly improved the yield of LCCs (66.4% based on Klason lignin), which was higher than the neutral aqueous dioxane extraction, and the extraction condition showed limited impact on the LCC structures and linkages. In the fractionation process, the low-molecular-weight LCCs containing a high content of carbohydrates (60.3-63.2%) were first precipitated by 70% ethanol from the extractable solution. The phenyl glycoside (PhGlc) bonds (13.0-17.0 per 100Ar) and highly acetylated xylans were observed in the fractions recovered by the precipitation with 100% ethanol. On the other hand, such xylan-rich LCCs exhibited the highest frequency of β-O-4 linkages. The benzyl ether (BE) bonds were only detected in the fractions obtained by acidic water precipitation.

Polyvinyl acetate emulsion adhesive has been widely used due to its good bonding performance and environmentally friendly properties. Indeed, the bonding performance can be further improved by copolymerizing with other monomers. In this study, the effect of the adjunction of redox initiator (hydrogen peroxide-tartaric acid, H₂O₂-TA) on the properties of the poly (vinyl acetate-butyl acrylate) (P (VAc-BA)) emulsion adhesive was investigated. With increasing dosage, the reaction became more complete and the obtained film was more compact, as identified via SEM. The core-shell structure of the emulsion particles was confirmed via TEM. Results indicate that while the initiator content increased from 0.5 to 1.0%, a clearer core-shell structure was obtained and the bonding strength of the plywood improved from 2.34 to 2.97 MPa. With the further incorporation of H₂O₂-TA (i.e., 1.5%), the bonding performance deteriorated. The optimum wood bonding strength (2.97 MPa) of the prepared P (VAc-BA) emulsion adhesive was even better than that (2.55 MPa) of a commercial PVAc emulsion adhesive, suggesting its potential application for the wood industry., Competing Interests: The authors declare no conflict of interest.

To better understand the variations of structural characteristics of lignin macromolecules during different growth years of Triploid of Populus tomentosa Carr, a novel lignin isolation procedure based on double ball-milling and enzymatic hydrolysis (DEL) was proposed in this study. The morphological distributions of lignin in the plant cell wall of these poplar wood samples were monitored by Confocal Raman Microscopy (CRM). The ultrahigh yields (105.1%-111.2%) of DELs were significantly higher than those (24.4-31.8%) of corresponding cellulolytic enzyme lignins (CELs). DELs and CELs were elaborately characterized by HPAEC, GPC, 2D-HSQC NMR and 31 P NMR techniques, and NMR results showed that DEL samples possess similar structural features as compared to CEL counterparts except for the decreased S/G ratio and p-hydroxybenzoate (PB) as well as increased p-hydroxyphenyl units (H). There are no obvious differences in the structural characteristics except for high contents of PB and H units in DEL-1, as well as high S/G ratio and β-O-4' linkages in DEL-5. It is believed that the DEL proposed in the present study can be used for characterizing the entire structural features of lignin macromolecules in the plant cell wall of different kinds of lignocellulosic biomass., (Copyright © 2017. Published by Elsevier B.V.)

A clear elucidation of structural feature of whole lignin in plant cell wall is of great importance for understanding lignin biosynthesis mechanism and developing lignin based chemicals or materials under the current biorefinery scenario. Swollen residual enzyme lignin (SREL) has been identified as an ideal representative for native lignin in the plant walls. To investigate the influence of preswelling conditions on the structural features, the SREL obtained through preswelling the ball-milled Eucalyptus wood powder in 2, 4 and 8% NaOH solutions and subsequent in-situ enzymatic hydrolysis were thoroughly characterized. A cellulolytic enzyme lignin (CEL) was also prepared as a comparison. The quantitative NMR analyses indicated that the relative contents of β-O-4' linkages in SRELs were higher than that in CEL. The lignin structure tended to undergo more destruction with the elevated NaOH concentration. A relatively low NaOH concentration (2% in this study), which could be applied to effectively remove hemicelluloses and transform cellulose structure from cellulose I to cellulose II, was competent to prepare SREL as an ideal representative for the protolignin. An optimization of SREL preparation was essential for a better understanding of the whole protolignin.

Background: Due to the unsustainable consumption of fossil resources, great efforts have been made to convert lignocellulose into bioethanol and commodity organic compounds through biological methods. The conversion of cellulose is impeded by the compactness of plant cell wall matrix and crystalline structure of the native cellulose. Therefore, appropriate pretreatment and even post-treatment are indispensable to overcome this problem. Additionally, an adequate utilization of coproduct lignin will be important for improving the economic viability of modern biorefinery industries., Results: The effectiveness of moderate alkaline ethanol post-treatment on the bioconversion efficiency of cellulose in the acid-steam-exploded corn stover was investigated in this study. Results showed that an increase of the alcoholic sodium hydroxide (NaOH) concentration from 0.05 to 4% led to a decrease in the lignin content in the post-treated samples from 32.8 to 10.7%, while the cellulose digestibility consequently increased. The cellulose conversion of the 4% alcoholic NaOH integrally treated corn stover reached up to 99.3% after 72 h, which was significantly higher than that of the acid steam exploded corn stover without post-treatment (57.3%). In addition to the decrease in lignin content, an expansion of cellulose I lattice induced by the 4% alcoholic NaOH post-treatment played a significant role in promoting the enzymatic hydrolysis of corn stover. More importantly, the lignin fraction (AL) released during the 4% alcoholic NaOH post-treatment and the lignin-rich residue (EHR) remained after the enzymatic hydrolysis of the 4% alcoholic NaOH post-treated acid-steam-exploded corn stover were employed to synthesize lignin-phenol-formaldehyde (LPF) resins. The plywoods prepared with the resins exhibit satisfactory performances., Conclusions: An alkaline ethanol system with an appropriate NaOH concentration could improve the removal of lignin and modification of the crystalline structure of cellulose in acid-steam-exploded corn stover, and consequently significantly improve the conversion of cellulose through enzymatic hydrolysis for biofuel production. The lignin fractions obtained as byproducts could be applied in high performance LPF resin preparation. The proposed model for the integral valorization of corn stover in this study is worth of popularization.

Eucalyptus grandis fibers were treated with hot-compressed water (HCW) and laccase mediator to enhance the fiber characteristics and to produce an active lignin substrate for binderless fiberboard production. The composition, morphology, and crystallinity index (CrI) analysis of fibers showed that the HCW treatment increased the CrI and lignin content of the treated fibers through partial removal of hemicelluloses. Simultaneously, the HCW treatment produced some granules and holes on the surface of the fibers, which possibly facilitated the accessibility of the laccase mediator. Milled wood lignins and enzymatic hydrolysis lignins isolated from the control and treated fibers were comparatively characterized. A reduction of molecular weight was observed, which indicated that a preferential degradation of lignin occurred after exposure to the laccase mediator. Quantitative (13)C, 2D-HSQC and (31)P NMR characterization revealed that the integrated treatment resulted in the cleavage of β-O-4' linkages, removal of G' (oxidized α-ketone) substructures, and an increase in the S/G ratio and free phenolic hydroxyls.

Corncob lignin was treated with pressurized hot water in a cylindrical autoclave in current investigation. With the aim of investigating the effect of reaction temperature and retention time on the distribution of degradation products, the products were divided into five fractions including gas, volatile organic compounds, water-soluble oil, heavy oil, and solid residue. It was found that hydrothermal degradation of corncob lignin in pressurized hot water produced a large amount of phenolic compounds with lower molecular weight than the raw lignin. Some phenolic and benzene derivatives monomers such as vanillin, 2-methoxy-phenol, 2-ethyl-phenol, p-xylene, and 1, 3-dimethyl-benzene were also identified in the degradation products. The products were further analyzed by GC-MS, GPC, 2D-HSQC, and (31)P-NMR to investigate their suitability for partial incorporation into phenol formaldehyde adhesive as a substitution of phenol. The results indicated that the reaction temperature had more effect on the products distribution than the retention time. The optimal condition for heavy oil production appeared at 290 °C with retention time 0 min. The compounds of heavy oil had more active sites than the raw lignin, suggesting that the heavy oil obtained from hydrothermal degradation of lignin is a promising material for phenol formaldehyde adhesive synthesis., (Copyright © 2014 Elsevier B.V. All rights reserved.)

This study is aimed at achieving the optimum conditions of hydrothermal treatment and acetylation of Populus fiber to improve its oil sorption capacity (OSC) in an oil-water mixture. The characteristics of the hydrolyzed and acetylated fibers were comparatively investigated by FT-IR, CP-MAS 13 C-NMR, SEM and TGA. The optimum conditions of the hydrothermal treatment and acetylation were obtained at170 °C for 1 h and 120 °C for 2 h, respectively. The maximum OSC of the hydrolyzed fiber (16.78 g/g) was slightly lower than that of the acetylated fiber (21.57 g/g), but they were both higher than the maximum OSC of the unmodified fiber (3.94 g/g). In addition, acetylation after hydrothermal treatment for the Populus fiber was unnecessary as the increment of the maximum OSC was only 3.53 g/g. The hydrolyzed and the acetylated Populus fibers both displayed a lumen orifice enabling a high oil entrapment. The thermal stability of the modified fibers was shown to be increased in comparison with that of the raw fiber. The hydrothermal treatment offers a new approach to prepare lignocellulosic oil sorbent.

Fungal treatment followed by FeCl3 treatment was used to improve saccharification of wood from Populus tomentosa. Combined treatments accumulated lignin and slightly degraded cellulose, whereas almost all hemicelluloses were removed. The white rot fungus, Trametes orientalis, and the brown rot fungus, Fomitopsis palustris, both accompanied by FeCl3 post-treatment resulted in 98.8 and 99.7 % of hemicelluloses loss at 180 °C, respectively, which were over twice than that of hot water pretreatment at the same level. In addition, the solid residue from the T. orientalis-assisted and F. palustris-assisted FeCl3 treatment at 180 °C released 84.5 and 95.4 % of reducing sugars, respectively: 1.4- and 1.6-fold higher than that of FeCl3 treatment alone at the same temperature. Combined treatments disrupted the intact cell structure and increased accessible surface area of cellulose therefore enhancing the enzymatic digestibility, as evidenced by XRD and SEM analysis data.

Bamboo (Phyllostachys pubescens) was successfully fractionated using a three-step integrated process: (1) autohydrolysis pretreatment facilitating xylooligosaccharide (XOS) production (2) organosolv delignification with organic acids to obtain high-purity lignin, and (3) extended delignification with alkaline hydrogen peroxide (AHP) to produce purified pulp. The integrated process was comprehensively evaluated by component analysis, SEM, XRD, and CP-MAS NMR techniques. Emphatically, the fundamental chemistry of the lignin fragments obtained from the integrated process was thoroughly investigated by gel permeation chromatography and solution-state NMR techniques (quantitative (13)C, 2D-HSQC, and (31)P-NMR spectroscopies). It is believed that the integrated process facilitate the production of XOS, high-purity lignin, and purified pulp. Moreover, the enhanced understanding of structural features and chemical reactivity of lignin polymers will maximize their utilizations in a future biorefinery industry., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Effective delignification of lignocelluloses is a very important to guarantee the economic feasibility of organosolv-based biorefinery. Eucalyptus chips were successively subjected to organosolv pretreatment (AEOP) and extended delignification (ED) process in the present study. The effects of delignification processes were scientifically evaluated by component analysis, SEM, and CP-MAS NMR techniques. It was found that the integrated process of organosolv pretreatment and subsequent delignification resulted in an effective delignification. The fundamental chemistry of the lignin obtained after these processes was thoroughly investigated by FT-IR, multidimensional NMR ((31)P-, (13)C-, and 2D-HSQC NMR), and GPC techniques. It was observed that an extensive cleavage of aryl ether linkages, ethoxylation, and some condensation reactions occurred in AEOP process, while α-oxidation mainly took place in alkaline hydrogen peroxide (AHP) process. It is believed that better understanding the fundamental chemistry of lignin facilitates the optimization of the delignification process. More importantly, well-defined of lignin polymers will facilitate their value-added applications in current and future biorefineries.

An environmentally friendly pretreatment process was developed to fractionate hemicelluloses and lignin from poplar wood by ionic liquid (IL) pretreatment coupled with mild alkaline extraction. Hemicellulosic and lignin fractions were obtained in high yields, amounting to 59.3% and 74.4%, respectively, which can served as raw materials for production of value-added products. The yield of glucose for the integrated pretreated poplar wood was 99.2%, while it was just 19.2% for the untreated material. The synergistic benefits of the removal of lignin and hemicelluloses, the increase of the cellulose surface area, and the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase resulted in the high glucose yield for the integrated pretreated substrate. Therefore, the IL based biorefining strategy proposed can integrate biofuels production into a biorefinery scheme in which the major components of poplar wood can be converted into value-added products., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

As one of the potential energy crops, Arundo donax Linn. is a renewable source for the production of biofuels and bioproducts. In the present study, milled wood lignin (MWL) and alkaline lignin (AL) from stems and foliage of A. donax were isolated and characterized by FT-IR spectroscopy, UV spectroscopy, GPC, ³¹P NMR, 2D HSQC NMR, and DFRC. The results indicated that both stem and foliage lignins were HGS type lignins. The semiquantitative HSQC spectra analysis demonstrated a predominance of β-O-4' aryl ether linkages (71-82%), followed by β-β', β-5', β-1', and α,β-diaryl ethers linkages in the lignins. Compared to stem lignins, foliage lignins had less β-O-4' alkyl-aryl ethers, lower weight-average molecular weight, less phenolic OH, more H units, and lower S/G ratio. Moreover, tricin was found to incorporate into the foliage lignins (higher content of condensed G units) in significant amounts and might be alkaline-stable.

The effect of proposed integrated pretreatment on enzymatic hydrolysis of poplar wood has been reported in Part 1. Part 2 of this work investigated the detailed structural features of the isolated lignin and hemicellulosic fractions, which were obtained in high yields. The chemical structures of these polymer fractions obtained were compared with the corresponding alkaline lignin and hemicelluloses extracted from the raw material without ionic liquid (IL) pretreatment. The yields of alkaline lignin and hemicelluloses obviously increased after the IL pretreatment. No apparent degradation occurred for both lignin and hemicellulosic fractions during this integrated pretreatment process. The lignin fraction (RCEL), which obtained after the enzymatic hydrolysis, exhibited high percentages of β-O-4' aryl ether linkages and S/G ratio. It is believed that the high molecular weight and high purity hemicellulosic and lignin fractions obtained can serve as raw materials for the production of value-added products., (Copyright © 2013 Elsevier Ltd. All rights reserved.)