查看更多>>摘要：? 2022 Elsevier B.V.In this study, enzymatic pretreatment combined with solvent-free microwave extraction (EP-SFME) was used to extract essential oils from fresh leaves of Pelargonium graveolens L′Herit. The effects of hydrodistillation and enzymatic pretreatment combined with solvent-free microwave extraction on the yield and quality of essential oils were compared. The essential oil yield from the EP-SFME method (0.29% ± 0.04%) was 26.09% higher than that from the conventional hydrodistillation method. The gas chromatography-mass spectrometry analysis results showed that the content of main components in the essential oil from the EP-SFME method was significantly increased, including citronellol (+8.60%), geraniol (+3.14%), citronellyl formate (+2.77%), and geranic acid (+1.54%). The content of oxygenated compounds was also far higher than that of the hydrodistillation method. The essential oil from the EP-SFME method showed stronger antidepressant potential, as determined by the inhibition rate of acetylcholinesterase (IC50 =73.3 μg/mL). In contrast, the essential oil from the EP-SFME method showed higher comprehensive antimicrobial activity, including Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, and Candida albicans, and antioxidant activity than that from the hydrodistillation method. Therefore, the EP-SFME method is a green and effective method for the extraction of high-quality essential oils from fresh leaves of Pelargonium graveolens L′Herit.
查看更多>>摘要：? 2022 Elsevier B.V.Flavonoids are natural bioactive substances with beneficial health effects against chronic diseases. Camellia oleifera Abel. (C. oleifera) has attracted attention because its seeds contain high levels of unsaturated fatty acids. Actually, flavonoids are also abundant in the C. oleifera seeds. However, the composition and distribution of flavonoid and overall molecular mechanism of flavonoid biosynthesis in the C. oleifera seeds have not been fully uncovered. To this end, metabolome, transcriptome, high-performance liquid chromatography, microscopic, and exogenous methyl jasmonate treatment analyses of C. oleifera seeds at different developmental stages were performed. Results revealed that the differential metabolites and genes were enriched in the flavonoid biosynthesis pathways in C. oleifera seeds. Flavonoid profiles presented dynamic patterns that changed with seed development, consistent with the pattern of gene regulation in the corresponding pathways. In total, 52 differentially accumulated flavonoids and 124 differentially expressed structural genes involved in flavonoid biosynthesis were identified. After weighted gene co-expression network analysis, three modules were highly interrelated with the accumulation of flavonoid components. The co-expression networks of these three modules were used to identify key candidate transcription factors associated with flavonoid biosynthesis, such as MYC2, bHLH3, bHLH18, MYB44, MYB86, WRKY26, and WRKY32. Based on these differentially accumulated flavonoids and key genes, the genetic and metabolic regulatory networks of flavonoid biosynthesis was proposed. Moreover, exogenous methyl jasmonate influenced the accumulation of diverse flavonoids in C. oleifera seeds. Potential regulatory factors identified in this study will contribute to the provision of molecular traces for in-depth research on flavonoid biosynthesis and product development for C. oleifera with higher value.
查看更多>>摘要：? 2022 The AuthorsBioactive molecules are those capable of interacting with living organisms, causing changes in them. Wood extractives contain important amounts of these molecules, and some of them have good antioxidant and antimicrobial activity, which favors their use as preservatives. Several different extraction methods are employed to obtain the extractives, some of which have been used for a long time. However, these conventional methods have significant disadvantages, being the most important ones high solvent, energy, and time consumption. To overcome these drawbacks, new extraction techniques are being developed whose aim is also the optimization of the process. Separation techniques such as chromatography and molecular distillation allow extractives purification and the acquisition of the desired molecules. This review aims to provide an overview of the extraction and purification methods used for wood bioactive molecules. To this end, issues such as raw material, solvent type, solid/liquid ratio (SLR), temperature, pressure, and extraction time are discussed. The application of extractives as preservatives for low durability woods is also analyzed. The study concludes that the quality and quantity of bioactive molecules, besides depending on the raw material, are determined by the employed methods and solvents to obtain these molecules. Therefore, the choice of method and solvent is of fundamental importance to achieve the desired results.
查看更多>>摘要：? 2022 Elsevier B.V.Superwetting cotton fabrics with surface wettability from underwater superoleophobic to superhydrophobic were designed and prepared by modification with polymerized plant polyphenol for on-demand oil/water separation. Hydrophilic poly(tannic acid) (PTA) particles were in-situ deposited onto the surface of polyethyleneimine (PEI)-coated cotton fabric. The resulting underwater superoleophobic cotton fabric (UWSOCF) was a water-removing material to separate water/light oil mixtures with a separation efficiency higher than 99.8%. After modifying UWSOCF with hydrophobic octadecylamine (ODA), superhydrophobic cotton fabric (SHCF) was obtained. SHCF was an oil-removing material suitable for separating water/heavy oil mixtures with a separation efficiency higher than 96%. Both UWSOCF and SHCF exhibited excellent mechanical robustness and environmental durability and could resist mechanical abrasion, tape peeling, high temperatures, organic solvents, and acidic/alkali erosion.
查看更多>>摘要：? 2022 The Authors2-(2-Phenylethyl)chromones (PECs), with extensive pharmacological activities, have been found in only few plant species and are the characteristic components of agarwood which is an expensive fragrant and resinous wood. However, little is known about PEC biosynthesis pathway. Here, three type III polyketide synthases (PKSs), AsPKS3, AsPKS4, and AsPKS5, highly expressed in the agarwood layer were isolated from Aquilaria sinensis and characterized. The qRT–PCR results showed that the expression of them was strongly induced by salt, salicylic acid (SA), or methyl jasmonate (MeJA). In addition, their expression levels were consistent with PEC accumulation in calli under salt treatment. AsPKS proteins exhibited multiple activities in vitro, including catalyzing the synthesis of p-hydroxybenzalacetone, feruloylmethane, 4-hydroxy-N-methyl-2(1H)-quinolone, and 1-methyl-2-phenethylquinolin-4(1H)-one (which has a structure similar to those of PECs). Moreover, AsPKS4 or AsPKS5 could also catalyze the production of pyrones in vitro. The pH and temperature optima for the p-hydroxybenzalacetone or 4-hydroxy-N-methyl-2(1H)-quinolone production of AsPKSs were found to be different. Protein structure prediction showed that the three AsPKSs have large active site entrances allowing binding of bulky substrates such as N-methylanthraniloyl-CoA. Additionally, the three AsPKS proteins were localized in the cytoplasm and nucleus. This study not only facilitates the synthesis of structurally diverse benzalacetones, quinolones, and pyrones but also indicates prime enzymes involved in the biosynthesis of PECs for future studies.
查看更多>>摘要：? 2022 Elsevier B.V.Cellulose Nanocrystals (CNCs) play a vital role in modern science & nanotechnology evolution. In this study, non-wood, i.e., Lagenaria siceraria peels, a food-industry waste was used as a source of CNCs. CNCs were successfully isolated from Lagenaria siceraria peels, and detailed characterization has been performed. The Fourier Transform Infrared Spectroscopy (FTIR) was performed to confirm the successful removal of other components from the waste peel. It holds a crystallinity index of 83% examined by X-ray diffraction (XRD). The rod-like morphology is established by Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FESEM), and Atomic Force Microscope (AFM). CNC acquired excellent thermal stability (>220 °C) established by Thermogravimetric analysis (TGA). The zeta potential value of ? 28.77 mV leads to the stability of the suspension. The birefringence of the anisotropic liquid crystalline CNCs proves that Lagenaria siceraria peels as an invaluable source for the production of CNCs for photonic and other advanced applications.
查看更多>>摘要：? 2022 Elsevier B.V.The unique hierarchical gradient structure of bamboo from the macro to nano scales and its remarkable combination of vascular bundles and parenchyma provide its high strength and toughness. Bamboo is an excellent engineering material that is widely used in construction and transportation, and its impact performance is an important indicator that reflects its structural stability. In this study, the finite element method was used to analyze the mechanical characteristics of bamboo splits under impact in simulations, and arc-shaped bamboo splits were tested to assess impact performance under puncture, thus, clarifying the relationship between bamboo age, density, and chemical composition and fracture load. As the bamboo age increased (from 2 to 4 and 8 years), the maximum impact load of bamboo first increased and then decreased. The maximum impact load of 4-year-old bamboo was 4373 N, which was 1.79- and 1.70-fold that of 2- and 8-year-old bamboo, respectively. Although the maximum impact load of 2-year-old bamboo was lower than that of 4-year-old bamboo, it nevertheless withstood secondary loads after fracture and was highly tough. Specimens exhibited both transverse and intergranular impact fractures, but the latter category comprised most of the fractures. The crack deflection, fiber stripping, and crack bridging caused by the gradient structure of bamboo enhanced its fracture load. There were clear correlations between the maximum load of bamboo impact and the density, moisture content, and chemical composition of bamboo. The establishment of structure–activity relationships between the bamboo impact load and physicochemical properties can guide the engineering applications of bamboo and provide a reference for biomimetic materials.
查看更多>>摘要：? 2022 Elsevier B.V.In recent years, many investigations have found that artificial sunscreen additives not only have allergic and endocrine disruption problems, but also found that these additives affect aquatic organisms such as corals. Therefore, finding alternative additives to satisfy the needs of users while ensuring environmental and ecological safety has become an important issue today. Natural sunscreen additives with low toxicity, low allergenicity and high environmental friendliness have become the focus of development of new sunscreens. It is known from previous studies that the renewable parts of Garcinia subelliptica are rich in benzophenones, biflavonoids and xanthonoids, indicating potential for application in sun protection. Hence, this study evaluated the potential of the renewable parts (branches, leaves and fruits) of G. subelliptica, and combined the concept of the circular economy to make natural sunscreen additives with environment-friendly value. The results showed that the phenolic compounds and flavonoids in the renewable parts of G. subelliptica are rich, endowing them with good sun protection efficacies and antioxidant ability via absorption of ultraviolet light and scavenging of free radicals, especially the biflavonoids in the leaves. These results indicated that the extract of G. subelliptica leaves has the most potential for development as natural sunscreen additives. The active ingredients in these leaves are worth further investigate. Future research can also combine urban forestry or community forestry policies to develop the renewable parts of G. subelliptica into environmentally friendly raw materials for natural sunscreen additives with multiple functions such as sunscreen and antioxidant, enhancing the utilization values.
查看更多>>摘要：? 2022 Elsevier B.V.Lignocellulosic biomass (LCB) is produced in large quantities throughout the world every year and represents a major sink for photosynthetically fixed carbon. However, in some countries, lignocellulosic materials are viewed as agricultural by-products and are often burned to quickly prepare the land for the next cropping season. This environmentally unfriendly practice contributes to greenhouse gas (GHG) emissions and the loss of renewable carbon-based resources. When used properly, LCB can be an inexhaustible source of renewable energy, soil conditioners, and other sustainable materials. To this end, leveraging microbial power to unlock the multifunctional value of LCB is presented as one of the very promising pathways toward sustainable development. However, LCB, despite its high carbon content, has a low nitrogen concentration, which may limit its microbial degradation in environments with little or no additional nitrogen. Fortunately, some cellulolytic bacteria can produce bioavailable nitrogen through nitrogen fixation and play a key role in LCB digestion in wood-boring organisms. In this review, we discuss how cellulolytic nitrogen-fixing bacteria (CNFB) can enhance the conversion of LCB into various bioproducts (e.g., biofuels and soil conditioners). Based on the knowledge of the biotechnological potential of CNFB disseminated in this review, there are prospects for further research to biovalorize LCB towards a carbon-neutral circular economy.
查看更多>>摘要：? 2022Biochar has great potential for the remediation of heavy metal pollution, but the adsorption instability and high cost of long-term soil remediation limit its industrial application. In this study, three common agricultural wastes were used to prepare biochar at temperatures ranging from 300° to 600°C and the correlative mechanisms among the preparation process, physicochemical characteristics, cost, adsorption properties, and stability of biochar were systematically studied. The results illustrated that with increasing pyrolysis temperature, the biochar yield decreased, whereas the stability and adsorption capacity increased. Economic analyses showed that biochar prepared from rice husks at 500 °C had the highest economic value (292.73 mg/$ for Pb2+, 84.29 mg/$ for Cu2+). In addition, biochar prepared using rice husk had the highest adsorption stability due to the dominance of complexation and ion exchange. The comprehensive analysis conducted in this study provides an evaluation of the biochar preparation process and its industrial applications.
NSTL
Elsevier