查看更多>>摘要：? 2022 Elsevier B.V.Application of polyethylene (PE) mulch in agriculture and horticulture is challenging due to scarce fossil-oil resources and serious environmental pollution. Therefore, bio-based mulches represent a promising alternative for petroleum-derived ones. From the lignocellulose from the whole corn stalk, the eco-benign cryogel absorbent and paper mulch has been modified by tartaric acid (TA) esterification and polyvinyl alcohol (PVA)/cationic starch (CSt) coating, respectively. This work reports a hybrid mulch of these two products via cellulosic partial-dissolution and regeneration processes and its excellent performance of water preservation for cultivation soil. The modification of TA molecules onto cellulose chains were confirmed by FTIR and X-ray diffraction, which showed the formation of ester bonds and crystallinity transition from cellulose I to the coexistence of cellulose II. SEM analyses proved a successful composite of TA-esterified cellulose absorbent and PVA/CSt-coated paper by ZnCl2-dissolved cellulose gel. The abundant H-bonding between interfaces of the coated paper and cellulose-derivative cryogel contributed to the favorable connection and thus mechanical properties, which both dry tensile strength (41.5 MPa) and wet tensile strength (35.6 MPa). The composites showed the reduction of water vapor transmission rate (WVTR) and oxygen transmission rate (OTR), which were 755.43 g/m2 day and 10.6 mL/m2/day, respectively, and enhancement of water absorbency for 210.3 g/g as increasing the cryogel thickness. The green and biodegradable strategy proposed in this study will broaden the application range of composite mulches in agriculture and forestry.
查看更多>>摘要：? 2021 Elsevier B.V.This study investigated the impact of different drying methods on Eucommia ulmoides Oliver male flowers (EUOMF), which were separately dried by hot air drying (HAD), microwave drying (MWD), and vacuum freeze drying (VFD) methods under different conditions. The results of HPLC showed that the geniposide (GP), and VB2 in the stamens were higher than those in the whole flowers. The contents of CGA, GPA, and GP in the stamens treated by MWD were 1.68, 1.52, and 5.88 times of those treated by HAD. However, compared with HAD, the destroy degree of free amino acid in MWD is up to 80%. VB2 and VE are the most damaged by VFD. The contents of VB2 and VE in the stamens treated by HAD were 11.5 and 1.85 times of those treated by VFD. Emphatically, principal component analysis indicated that the optimal drying conditions was MWD. Based on the economic efficiency, MWD is more suitable to produce the EUOMF tea than other methods for industrialization process.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, cellulose nanofibrils (CNFs) were directly prepared after autohydrolysis of eucalyptus raw materials. The effect of different autohydrolysis times on the hydrogen bond structure, micro-structure and properties of CNFs were analyzed by FTIR peak fitting, two-dimensional infrared, TGA, TEM and X-ray diffractometer. The results showed that the autohydrolysis treatments could obviously lead to the sequence of hydrogen bond changes in CNFs as follows: v(weak hydrogen bond) >v(free hydroxyl) >v(O(3)H.O(5)) >v(O(2)H.O(6)) > v(O(6)H.O(3′)), and further impact in crystallite size of CNFs. With the increase of the autohydrolysis strength, the crystallite size of CNFs on the 11ˉ0 crystal plane could be reduced by up to 26%, but the crystallite size on the 110 crystal plane and the 200 crystal plane increased by 24.5% and 22.6%, respectively. These microstructure changes finally increased the crystallinity index of CNFs, and then resulted in their high thermal stability.
查看更多>>摘要：? 2021 Elsevier B.V.In the present investigation, pollen morphology and viability of four Ocimum L. species viz. O. sanctum (CIM-Angana), O. basilicum (CIM-Saumya), O. gratissimum, and O. kilimandscharicum were studied. Morphological characters were observed using scanning electron and light microscopy. Pollen of all the four studied Ocimum species have hexacolpate apertures with varied aperture length and width. The exine ornamentation was reticulate and bi-reticulate. O. basilicum has large size (53.9 μm) pollen grains and rest three have medium sized pollen. The viability of pollen was assessed through staining dyes such as 2,5-diphenyl tetrazolium bromide (MTT) and 2,3,5-triphenyl tetrazolium chloride (TTC) and in vitro pollen germination method. O. basilicum possessed maximum viability (92.4%) whereas least viability was found in O. sanctum (38.2%). The maximum pollen germination percentage and tube growth were observed in the semisolid medium gelled with phytagel supplemented with 15% sucrose, 15% PEG, 6.4 mM boric acid and 7.3 mM calcium nitrate. O. basilicum showed the highest germination percentage (90.3%) followed by O. kilimandscharicum (57.1%), O. gratissimum (42.5%) and O. sanctum (25.5%). Pollen of the four Ocimum species were stored at different temperatures viz. 37 °C, + 4 °C, 0 °C, ? 20 °C, and ? 80 °C for 75 days. The highest pollen germinability of all the four Ocimum species was observed at ? 20 °C. This study can be helpful in taxonomic identification of Ocimum species and further utilized in conservation and improvement of different Ocimum species by cross-hybridization breeding programmes.
查看更多>>摘要：? 2021 Elsevier B.V.This study reported that 5-sulfosalicylic acid (5-SSA), a solid acid with hydrotropic properties, could efficiently and rapidly fractionate poplar biomass in an aqueous solution at mild conditions. The experimental results showed that 5-SSA-treatment could deconstruct the biomass recalcitrant intercellular structure and has excellent potential in lignin and hemicellulose dissolution and glucose release through subsequent enzymatic hydrolysis. Under the optimum conditions (80 wt% aqueous 5-SSA solution, 110 °C, and 60 min), a lignin removal rate of approximately 69.97%, cellulose recovery yield of more than 80.18% saccharification yield of 76.1% were achieved. 5-SSA acted as a catalyst to depolymerize lignin and hemicellulose by cleaving ether bonds and served as a solvent to dissolve lignin macromolecules by forming 5-SSA clusters and aggregates in water during fractionation. Density functional theory (DFT) indicated that strong H-bonding interactions between 5-SSA and lignin fragments contributed to the breakage of H-bonding network between lignin fragments.
查看更多>>摘要：? 2021 Elsevier B.V.Efficient modification and decrystallization of cellulose Iβ in lignocellulosic biomass are potential ways to overcome biomass recalcitrance and facilitates enzymatic degradation. Herein, we have treated moso bamboo and microcrystalline cellulose separately by either alkali or ethylenediamine (EDA) treatments, as well as using both in succession. The pretreatments successfully transformed the initial cellulose Iβ allomorph into cellulose II, IIII, and cellulose IIIII. Crystal structures and crystallinities were determined by Rietveld X-ray diffraction and CP/MAS 13C NMR. Comparatively, the samples that were sequentially treated by EDA and NaOH had low crystallinity (~50%), larger d-spacings of ~4.4 ? for the hydrophobic (110) planes, and less condensed microfibrillar aggregation. The factors simultaneously contributed to as high enzymatic hydrolysis yield as 89.5% and 91.7% respectively, followed by the yields of mercerized cellulose II and cellulose IIIII allomorph. The stepwise allomorphic transformations may provide new strategies on improving efficiency of saccharification process and biomass utilization.
查看更多>>摘要：? 2022 Elsevier B.V.Paeonia is famous as ornamental, medicinal plant, and edible oil crop in China. The seeds of peonies are rich in unsaturated fatty acids, monoterpene glycosides, sterols and stilbenes which have antioxidant and anti-inflammatory effects, etc. In this study, the composition and content of stilbenes in the seed coat extracts (SCE) from 50 populations of 18 species and two subspecies of Paeonia were determined by high performance liquid chromatography - diode array detection (HPLC-DAD). The results showed that the composition and content of stilbenes, especially suffruticosol B and gnetin H, differed significantly between Paeonia species, while there were small differences between populations of the same species. All the samples were clustered into two groups according to the stilbenes in SCE. The difference between the two groups was mainly reflected in the content of suffruticosol B and gnetin H. Furthermore, all samples showed high antioxidant activity, which was significantly positively correlated with the total polyphenol content. The SCE of P. anomala and P. lactiflora at different concentrations could effectively inhibit the production of matrix metalloproteinase ? 1 (MMP-1) in keratinocytes, and then achieve the effect of inhibiting cell aging. This study provided a valuable reference for the value-added utilization of Paeonia seed coat.
查看更多>>摘要：? 2022 Elsevier B.V.Biocides with lower environmental and human health impacts have been demanded by the society. Based on bioeconomy concepts, we investigated the potential of water-soluble fractions separated from the pyrolytic lignin of fast-pyrolysis bio-oil for wood protection against physical and biological agents. The high-viscosity crude bio-oil was fractionated in two oil-to-water ratios, 1:50 and 1:100, by separating the pyrolytic lignin and water-soluble fractions. Additionally, exfoliated nanostructures of bentonite were incorporated into water-soluble fractions to form bicomponent systems to improve the protection degree. These materials were then characterized in terms of morphological, chemical, and biological features. The preservative formulations were impregnated into pinewood (Pinus taeda), with subsequent evaluation of the morphology, wettability, thermal aspects, and antifungal activity of treated wood to determine the degree of protection. The water-soluble fractions severely impacted the water repellency of wood with contact angles up to 115°, and normal growth of the decay fungi (Trametes versicolor and Gloeophyllum trabeum). Also, the addition of nanobentonite in the formulations improved the action of the water-soluble fractions against the physical and biological agents, specifically for G. trabeum the decay can be decreased around three times compared to untreated wood. The combined action of water-soluble fraction and nanobentonite supported the wood water repellency with time-dependent stability of the contact angle and excellent antifungal activity, which is partially explained by the chemical composition of the water-soluble fraction and physical barriers formed by the nanobentonite on the surface. Therefore, a single use of water-soluble fractions or in combination with nanobentonite has potential for application as a bio-based wood protection process.
查看更多>>摘要：? 2022 Elsevier B.V.Undesirable impacts of synthetic insecticides on environmental and human health have contributed to the increasing use of biopesticides as suitable alternatives to traditional products in integrated pest management programs. Liquids obtained from pyrolysis of lignocellulosic biomass have been investigated over the last two decades as potential sources of insecticidal compounds. However, a systematic literature survey is needed to analyze the lethal and sublethal effects of pyrolysis liquid on insect pests and their ecotoxicological risks on nontarget organisms. This review examines the aspects mentioned about above. The overall analysis indicates that pyrolytic liquids produce acute toxicity, repellent effect, irritability, feeding deterrence, and development disruption in insect pests of economic, medical, and veterinary importance. In addition, these liquids present low toxicological effects on aquatic and terrestrial nontarget organisms. The information to date regarding the toxicological effect of pyrolysis liquids on mammalian models remains scarce and controversial. Finally, commercialization opportunities for bio-oils as cost-effective insecticides are discussed.
查看更多>>摘要：? 2022 Elsevier B.V.To alleviate the exhaustion of petrochemical resources and reduce their use in the polyurethane industry, biopolyols derived from dextrin and glycerol were prepared and used in rigid polyurethane foam (RPUF). Through simple and eco-friendly physical mixing, biopolyols with different dextrin contents were obtained, and the effects of different biopolyols on the foaming process, combustion behavior, mechanical properties and biodegradability were investigated. The apparent density of the RPUF ranged from 31.4 kg/m3 to 49.1 kg/m3. Compared with conventional foam, RPUF based on dextrin and glycerol had a higher normalized compressive strength and biodegradability. In addition, when the ratio of dextrin to glycerol in the biopolyol was 1/1, the self-extinguishing time of the foam was only 9 s, and the LOI value was 14.5% higher than that of conventional foam. These results demonstrated that dextrin-glycerol polyols can completely replace petrochemical polyols to prepare water-foamed RPUF with excellent comprehensive properties.
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