Search

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. • The Chinese pine branches were systematically revealed. • The thickness of cell wall was enhanced gradually in late wood. • The lignin macromolecule polymerized gradually with Chinese pine growth. • The alkali-extracted hemicelluloses mainly consist of galactoglucomannans and arabinoglucuronxylan. [ABSTRACT FROM AUTHOR]

Achieving efficient fractionation and tailored downstream high value-added applications of bulk industrial waste biomass could guarantee the sustainability of biorefinery strategies. A synergistic and mild alkaline deep eutectic solvent‑hydrogen peroxide (DES-HP) pretreatment was designed in this study to significantly reduce pretreatment costs while achieving efficient fractionation of industrial xylose residues for preparing high antioxidative lignin and high enzymatic digestion of cellulose substrates for subsequent bioenergy and biochemicals production. The results demonstrated that this DES-HP pretreatment had admirable biomass deconstruction ability and the obtained DES-HP lignin displayed well-preserved structures and excellent antioxidative properties, which facilitated downstream catalytic degradation as well as the production of lignin-based materials and chemicals. Under the optimal condition (60 °C, 2 h, 10 FPU/g), the fermentable glucose yield of the DES-HP pretreated substrate could achieve 95.89%. In conclusion, this synergistic DES-HP is an ideal pretreatment strategy for the current tailored biorefinery scenario of industrial lignocellulosic biomass. [Display omitted] • Synergistic DES-H 2 O 2 pretreatment was developed for fractionation of xylose residue. • The precipitation of DES-HP lignin was achieved by injecting CO 2. • The DES-HP lignin had well-preserved structure with high antioxidant activity. • The excellent delignification (97.1%) was achieved by synergistic DES-HP pretreatment. • The highest glucose yield (95.9%) had been achieved under the mild condition. [ABSTRACT FROM AUTHOR]

Elucidating the structural variations of lignin during the pretreatment is very important for lignin valorization. Herein, poplar wood was pretreated with an integrated process, which was composed of AlCl 3 -catalyzed hydrothermal pretreatment (HTP, 130–150 °C, 1.0 h) and mild deep-eutectic solvents (DES, 100 °C, 10 min) delignification for recycling lignin fractions. Confocal Raman Microscopy (CRM) was developed to visually monitor the delignification process during the HTP-DES pretreatment. NMR characterizations (2D-HSQC and 31P NMR) and elemental analysis demonstrated that the lignin fractions had undergone the following structural changes, such as dehydration, depolymerization, condensation. Molecular weights (GPC), microstructure (SEM and TEM), and antioxidant activity (DPPH analysis) of the lignins revealed that the DES delignification resulted in homogeneous lignin fragments (1.32 < PDI < 1.58) and facilitated the rapid assemblage of lignin nanoparticles (LNPs) with controllable nanoscale sizes (30–210 nm) and excellent antioxidant activity. These findings will enhance the understanding of structural transformations of the lignin during the integrated process and maximize the lignin valorization in a current biorefinery process. [Display omitted] • The microcosmic distribution and changes of lignin were visualized investigated. • Structural changes of lignin during the integrated HTP-DES process were illustrated. • Synergistic HTP-DES method was developed for fractionation of lignin. • High yields of tailored lignin nanoparticles were obtained. • Possible chemical variations of lignin during the synergistic HTP-DES were investigated. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cationized lignin was prepared rapidly and efficiently from industrial lignin. • Enhancing the water solubility and antimicrobial properties of industrial lignin. • Biodegradable lignin-based antimicrobial nanofiber membranes were prepared. • Lignin-based NFMs exhibited outstanding breathability and anti-UV properties. • NFMs had excellent antimicrobial performance (100%) against E. coli and S. aureus. Industrial lignin is underutilized as an abundant natural aromatic resource, resulting in a serious waste of biomass resources. In this study, a strategy was developed to efficiently achieve cationization of industrial lignin, which not only could increase the water solubility of the industrial lignin for good compatibility with polyvinyl alcohol (PVA), but also incorporated quaternary ammonium groups to improve the antimicrobial performance. The results showed that the cationized lignin products could be obtained by reacting at 75 °C for only 20 min and had good compatibility with PVA in aqueous systems, which not only shortened the lignin cationization time, but also reduced the amount of cationization reagent. By integrating the electrospinning technique, the nanofiber membranes with excellent antimicrobial performance can be produced for the field of medical dressing. With the addition of 7 wt% of the cationized lignin, the novel developed antimicrobial nano-medical dressing exhibited excellent breathability (61.08 mm/s), anti-UV properties, and compatibility with portable spinning technique. In addition, the cationized lignin-based nanofiber membranes had excellent antimicrobial performance, with an antimicrobial ratio of 100 % (Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli), as well as being biodegradable. In conclusion, this strategy could realize the cationization modification of industrial lignin while expanding the application in medical dressings and improving the economic sustainability of biorefinery strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • The effect of lignin structure on the flocculant preparation was discussed. • The dual function of flocculants was regulated at the actual molecular level. • Uniform lignin improved the synthesis efficiency and performance of LBF. • The stable core skeleton could improve the flocculation efficiency of LBF. • The sterilization ability was mainly affected by the charge density. Lignin, an inedible yet sustainable aromatic resource, has great commercial prospects as raw material to prepare flocculants with efficient flocculation coupled with sterilization. However, the troublesome heterogeneity of lignin is the bottleneck for the large-scale production of highly efficient flocculants. In this study, an easy to operate organic solvent fractionation approach was first applied to separate industrial lignin and generate several homogeneous fractions, and the polydispersity of lignin improved from 2.80 to 1.30–1.85. Subsequently, a series of lignin-based flocculants were synthesized in a UV-induced biphasic polymerization system using different lignin fractions (F0-F4). Surprisingly, the lignin-based flocculants L F1 and L F2 , which were prepared from lignin F1 and lignin F2 fractionated by ethyl acetate and ethanol, respectively, exhibited over 99% removal rate and excellent sterilization efficiency on E. coli suspensions. The improved efficiency could be attribute to the more homogeneous structure of the fractionated lignin. Moreover, more G units and phenolic hydroxyl groups in lignin contributed to the increase of its copolymerization activity, while the low molecular weight and excellent hydrophilicity led to superior dispersibility and reactivity accessibility in biphasic polymerization. The purification test of E. coli suspensions showed that the flocculation performance of lignin-based flocculants was not only affected by charge density and molecular weight, but also by the balance of amphiphilicity, and its sterilization ability was mainly determined by charge density. The effect of lignin structure on the preparation and performance of lignin-based flocculants was fully explored at the actual molecular level, which has important enlightening significance for the application of lignin in wastewater recycling. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrafast alkaline DES pretreatment was developed for fractionation of xylose residue. • The precipitation of lignin and recovery of DES was achieved by injecting CO 2. • Recovered alkaline DES still had distinguished pretreatment performance. • The obtained DES lignin nanoparticles (LNPs) had excellent antioxidant activity. • The highest glucose yield (90.12%) had been achieved under the mild condition. 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. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sustainable EXA process is proposed for total valorization of corncob. • All lignocellulose components are valorized with the carbon utilization of 79.6%. • The overall revenue of the EXA biorefinery process reached 1414.55 USD. • GHG intensities shows a much lower GHG emissions intensity per USD. Lignocellulose, as the most abundant type of inedible biomass, is considered as a promising renewable feedstock for making fuels, chemicals, and materials. However, its complex structure makes most of current biorefinery processes suffer from low resource utilization rates, high energy consumption or ill-defined market orientation of the obtained products. Here, we propose and evaluate the EXA (Ethanol, Xylose, Adhesive) biorefinery strategy based on current xylose industry. This process integrates four conversion and separation stages to consecutively produce ethanol, xylose, and adhesive with total carbon utilization of 79.6%. The key innovation is the establishment of an easy-to-operate process for direct production of high-quality adhesive from a lignin-rich liquid fraction that makes the overall process significantly more sustainable. Techno-economic analysis (TEA) shows that the revenue of proposed EXA process increases more than 110 times compares with the current process and life cycle assessment (LCA) demonstrates a much lower CO 2 footprint from an environmental burden per unit of revenue perspective. [ABSTRACT FROM AUTHOR]