查看更多>>摘要：? 2022 Elsevier B.V.Lignin is the second abundant natural renewable after cellulose. Pyrolysis is usually transformed lignin into high value-added platform compounds. In order to fully utilized lignin, the pyrolysis mechanism needs an in-depth understanding. Herein we performed density function theory (DFT) calculation to unveil the initial mechanism of pyrolysis of 9 representative β ? O? 4 lignin dimer model compounds with phenyl-1, 3-propanediol as the main body. Several cleavage pathways were investigated, including Cβ?O bond breaking（Cβ?O bond homolysis reaction, Maccoll elimination reaction and retro-ene fragmentation reaction） and Cα?Cβ bond breaking. Results show that the substituents on the B-ring have a greater effect on the pyrolysis pathway of lignin dimer than that on the A-ring. When no substituent on the ortho-position of B-ring, the retro-ene fragmentation reaction is the dominant pathway. And, its main reason is these structures have no steric hindrance in the process of hydrogen transfer. The Cβ?O bond homolysis is the dominant pathway when methoxy group exists on ortho-position of B-ring. Maccoll elimination reaction also has certain advantages due to the influence of electronic factors of methoxyl group on ortho-position of B-ring. The cleavage reaction of Cβ?O bond is always prior to that of Cα?Cβ bond. The effect of water molecules on the pyrolysis reaction has been also discussed. The results showed that H2O could promote the Maccoll elimination I reaction, but did not change the dominant pyrolysis mechanism.
查看更多>>摘要：? 2022Enzymatic hydrolysis lignin (EHL) from the biorefinery industry has been considered an ideal carbon source to prepare high-performance carbonaceous electrodes due to its high aromaticity and abundance. However, the severe agglomeration of the directly carbonized EHL results in insufficient lithium storage sites and inferior transfer kinetics. Herein, a delicate strategy of pyrolytic gas exfoliation and template mediation through ZnCO3 and ZnC2O4 decomposition was developed to engineer the microstructure of EHL-derived carbonaceous material (ECM) at 650 °C for robust lithium storage. The mesoporous ECM with an interconnected grape-like (200 nm) network is prepared by single CO2 exfoliation and ZnO templating. Surface micropores are engineered by temporary ZnO activation at 500–650 °C. The blocky ECM with coexisting micro/mesopores is prepared by dual CO/CO2 exfoliation and ZnO templating. The tempestuous release of CO2 produces deep micropores. The developed mesoporous structure boosts fast Li-ion transportation and accessibility for defects. In addition, the nanostructured grape-like (200 nm) network exposes active surface defects and shortens the charge-diffusion distance. Thus, the mesoporous ECM displays a robust capacity (534.1 mAh·g?1 at 0.2 A·g?1), superior rate capability (323.4 mAh·g?1 at 1 A·g?1) and excellent cycling stability. The blocky ECM with coexisting micro/mesopores shows better lithium storage performance than the microporous blocky ECM prepared by ZnCl2 activation.
查看更多>>摘要：? 2022 Elsevier B.V.The fully biobased polylactide/epoxidized natural rubber (PLA/ENR) blend usually shows poor mechanical properties due to the coarse phase-separated morphology with low interfacial adhesion. Herein, we report a novel strategy to tailor the phase morphology and interfacial adhesion of PLA/ENR blend by partial crosslinking ENR with sebacic acid (SA). A series of partially crosslinked sebacic acid modified ENRs (mENRs) with different crosslinking degrees combining with reactive epoxy and carboxyl groups were simply prepared by mixing ENR with SA with 1-methylimidazole as a catalyst. In-situ interfacial compatibilization occurs during melt blending PLA with mENR through reaction between reactive groups of mENR and PLA. The phase morphology especially particle diameter and size distribution of dispersed mENR phase can be regulated by the crosslinking degree of mENR. The morphology and interface of PLA/mENR (80/20, w/w) were tuned finely when mENR-1 (SA/ENR=1/100, mol/mol) with gel fraction of 51% was used to blend with PLA, thus leading to drastically enhanced toughness with impact strength, elongation at break, and tensile toughness of 477.6 J m?1, 427% and 100.3 MJ m?3, which were ~13.8, ~35.6, and ~18.9 times higher than those of neat PLA, respectively. The highly-toughened PLA/mENR blend follows a toughening mechanism of internal mENR cavitation induced matrix shear yielding and plastic deformation.
查看更多>>摘要：? 2022 Elsevier B.V.Preceding bioethanol generation, the pretreatment of lignocellulosic biomass with alkali leads to the release of toxic effluents. In the light of growing environmental concerns, there is a strong need to minimize the pollution of water bodies and agricultural land through alternative strategies. Successive recycling of alkali black liquor (ABL), obtained from earlier pretreatment batch, may cut down the toxic effluents by many folds. The present study was conducted to evaluate the delignification performance of ABL for pretreatment of rice straw through recycling. Results indicated that instead of disposing ABL, it can be reused for at least up to five consecutive cycles. Furthermore, saccharification of ABL pretreated biomass using Cellic CTec2 was evaluated and morphological and chemical alterations were analyzed. Over the seven cycles, efficacy of delignification remained up to 60.36% and the enzymatic conversion of cellulose ranged between 99% (1–2 cycles) to 74% (7th cycle). Scanning electron micrographs indicated delignification of ABL pretreated rice straw samples. Crystallinity indices (CrI) of the ABL pretreated and enzyme treated biomass were found to change from 53.70% to 27.96% as compared to untreated rice straw (45.07%) and enzyme treated raw rice straw (42.16%). The present study suggests that the ABL could be used for pretreatment of rice straw, since no adverse effects were noticed on the delignification and saccharification due to ABL recycling.
查看更多>>摘要：? 2022 Elsevier B.V.Clarisia racemosa (guariúba), Moraceae, is a native tree of the Amazon region, with timber value in the local market and for export. Aiming to contribute to the biological study of the crude extract, we carried out its hydroalcoholic extraction and physicochemical characterization. The results showed that the wood had the following chemical composition: cellulose (40.1%), hemicellulose (18.34%), lignin (29.40%), extractives (10.7%), and ash (0.79%). The extract obtained showed a high content of phenolics and through liquid chromatography tests, it was possible to determine 17 compounds. Therefore, we evaluated its biological properties (antioxidant, antiglycant, in vitro and in vivo toxicity, antitumor, antimicrobial and photoprotective) to use it as a raw material in cosmetic and pharmaceutical formulations. The extract showed moderate antioxidant activity, it was also able to inhibit antiglycant reactions. And it showed no toxic effects in vitro and in vivo assays. Highlighting antiproliferative activity against MCF-7, T47D, DU-145, and Jurkat tumor cells. As reported in the literature, these models are still being used as a predictor of cytotoxicity. Regarding the in vitro antimicrobial assays, the extract showed activity against Staphylococcus aureus with a minimal inhibitory concentration similar to the oxacillin pattern. Finally, it was able to promote photoprotective activity in vitro at non-toxic concentrations. This study shows the potential of the hydroalcoholic extract of Clarisia racemosa to be used as a component in cosmetic and pharmaceutical formulations.
查看更多>>摘要：? 2022 Elsevier B.V.Malassezia restricta is associated with many human diseases. Currently, the limited number of antifungal drugs and the rising resistance of M. restricta have prompted research into safer, and more effective antifungal alternatives. In this study, we aimed to investigate Zanthoxylum schinifolium Siebold & Zucc. essential oil (ZSEO) with respect to its chemical composition, antifungal activity, and potential modes of action against M. restricta. Linalool (34.15%), limonene (21.24%), and sabinene (10.39%) were identified to be the predominant components of ZSEO. Moreover, ZSEO showed antifungal activity against M. restricta, with minimum inhibitory concentration and minimum fungicidal concentration values of 2.5 and 10.0 mg/mL, respectively. Further, cell membrane damage assays showed that interactions between ZSEO and cell membrane resulted in increased Zeta potential and cell membrane depolarization. Moreover, ZSEO induced lipid disorder in cell membrane, resulting in increased cell membrane fluidity. Moreover, oxidative stress experiments revealed that ZSEO could inhibit cell metabolism activity, and disrupt the homeostasis of reactive oxygens species. Finally, electron microscopy analyses confirmed the morphological and ultrastructural changes of M. restricta cells. These findings support ZSEO as a potential antifungal agent to control M. restricta and prevent related diseases.
查看更多>>摘要：? 2022 Elsevier B.V.Pathogenesis-related protein 1 (PR-1) is an important defense protein stimulated by adverse environmental conditions and is used in plants as a molecular marker of systemic acquired resistance (SAR). Few information is available regarding the function and the expression pattern of the PR-1 gene in sugarcane (Saccharum spp. hybrids). In this study, 19 PR-1 genes (SsPR1.1- SsPR1.19) were identified in the genome of Saccharum spontaneum and these genes were distributed into three phylogenetic groups. A full-length cDNA clone of ScPR1 was obtained from sugarcane cultivar ROC22 and this clone shared highest homology of amino acids (83.5%) with SsPR1.14 of phylogenetic Group D. After infection with Acidovorax avenae subsp. avenae (Aaa), transcript expression of the ScPR1 gene was significantly upregulated (6.1–11.1) in ROC22 (resistant to Aaa). This gene was only upregulated 2.1–6.3 times in sugarcane cultivar MT11–610 (susceptible to Aaa) during a 24–72 h post-inoculation (hpi) period. ScPR1 was also upregulated in sugarcane tissues (root, stem, and leaf) under NaCl, PEG6000, and SA (salicylic acid) treatments in both cultivars, except for the stems of MT11–610 plants under PEG6000 stress and roots of the two cultivars under NaCl stress. Transgenic lines of Arabidopsis thaliana overexpressing ScPR1 were enhanced in tolerance to NaCl and mannitol dehydration stresses and to infection by the bacterial pathogen Pseudomonas syringae pv. tomato, strain DC3000 (Pst DC3000). Meanwhile, the transcript expressions of the defense genes (PR-3, PR-4, PR-5, and PDF1.2) involved in SA and JA/ET (jasmonic acid/ethylene) signaling pathways were also increased in these same Arabidopsis transgenic lines after Pst DC3000 attack. These findings suggest that the ScPR1 gene plays an important role in the regulation of tolerance to biotic and abiotic stresses in sugarcane, in Arabidopsis, and most likely in other plants.
查看更多>>摘要：? 2022 Elsevier B.V.Bamboo is among the short-rotation and dedicated energy crops which serve as lignocellulosic feedstock for future bio-refinery. A pilot scale microwave fractionation system (PMFS) was developed and used for the organosolv fractionation of bamboo sawdust. The key component of the system, a 1000 L microwave-heating reactor, was designed with unique features for high efficiency of microwave energy utilization and uniform temperature distribution. More than 800 kg reactant can be heated at 65% energy efficiency with temperature differences between top and bottom reactor positions of less than 4 °C. The operational parameters of the PMFS were investigated, and the fractionation products from the PMFS process were characterized and compared with those obtained from lab scale experiments. Higher lignin (93.2%) and hemicellulose (84.7%) removal rates without serious cellulose degradation (cellulose retention 89.1%) were achieved with the PMFS. Recovered lignin has relatively narrow molecular weight distributions (polydispersity index ≈ 2). The mass balance of the fractionation process showed that 81.5% utilization efficiency of the bamboo feedstock was obtained by organosolv fractionation with the PMFS. The results from this study provide insightful information for the industrial implementation of microwave-assisted thermochemical conversion of lignocellulosic biomass.
查看更多>>摘要：? 2022 Elsevier B.V.As a low-cost and light-weight flexible rope, the production and use of straw rope can promote the transformation of straw into industrial raw materials and improve the utilization rate of straw. However, non-standard production makes the straw rope prone to failure and breakage. In this paper, the Chinese Zhendao 10# variety was selected, and mechanical tests were carried out on the components of rice fiber and rice stem. The tensile strength of the stem is 29.02 MPa, the elastic modulus is 1.03 GPa, and the shear strength is 8.52 MPa. The strength of rice fiber satisfies the Weibull distribution and has been verified by experiments; and the statistical strength of stem fiber is used for the strength analysis of straw rope. Secondly, this paper establishes the strength model of the rice straw rope and explores the failure mechanism through tensile test and explicit dynamic simulation. The results showed that shear failure of rice stem and tensile failure of stem fiber are the main mechanisms for the failure of straw rope. The stress distribution of the straw rope is consistent with the mathematical model. The research could provide a new idea and method for the strength prediction and evaluation of straw rope.
查看更多>>摘要：? 2022 Elsevier B.V.Biomass activated carbon (AC) is a widely sought-after renewable resource and possesses excellent electrochemical properties, which can be further enhanced if heteroatoms are doped on the surface of AC. Adsorption methylene blue (MB) with activated carbon (AC) allowed N/S atoms be adsorbed on the AC outer layer to prepare the supercapacitors cathode materials with excellent electrochemical performance, long service life, and low production cost. The results showed that the substance of component N and S increment from 1.31% and 0–2.91% and 0.7% on surface of adsorbed AC, respectively, and its specific surface area (SSA) was 3198.04 m2/g. The greatest capacitance was 491.2 F/g and it had an increasement of 70.67% contrasted with non-adsorbed analog, after 5000 cycles of charged and discharged, and it still had a capacitance retention rate of 89.8%.
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