查看更多>>摘要：? 2022 Elsevier B.V.Fusarium oxysporum GG22 is an endophytic fungus isolated from the leaves of Rehmannia glutinosa and shown to promote the growth of R. glutinosa. There is currently no in-depth study on the effect of plant growth-promoting endophytic fungi on the defensive metabolic response of medicinal herbs.A symbiotic system of GG22 with R. glutinosa tissue culture seedlings was established to analyze the effect of GG22 infection on the biomass of R. glutinosa tissue culture seedlings and on the accumulation of secondary metabolites. Antioxidant enzymes (SOD, POD and CAT) and endogenous signaling molecules (NO and H2O2) were examined. Quantitative real-time PCR was used to analyze the expression of enzyme genes related to secondarymetabolites. GG22 promoted the growth of the plant height, leaf area, fresh weight, and dry weight of R. glutinosa tissue culture seedlings and significantly increased catalpol and verbascoside. After GG22 infection, the activities of the antioxidant enzyme system (SOD, POD, CAT) of R. glutinosa increased differentially. In addition, significant accumulation of NO and H2O2 signaling molecules occurred. According to the analysis of the expression of genes encoding key biosynthesis enzymes for iridoid glycoside and verbascoside components in R. glutinosa, the levels of AACT, HMGR, DXR, GS, 4CL, C4H and C3H were all significantly increased after GG22 infection. Therefore, it is speculated that infection with the endophytic fungus GG22 induces a burst of reactive oxygen species and NO in plants to activate or enhance the expression of related enzymes in primary metabolic pathways, thereby increasing secondary metabolite contents in R. glutinosa. Our results confirmed that GG22 not only contributes to the stimulation of R. glutinosa growth but also enhances secondary metabolism, thus demonstrating its application potential as a bio-fertilizer for R. glutinosa cultivation.
查看更多>>摘要：? 2022 Elsevier B.V.The objective of the current research endeavor is to explore the potential of novel natural lignocellulosic crop-residue fibers (husk) extracted from the finger millet (Eleusine coracana) and barnyard millet (Echinochloa frumentaceae). The extracted finger millet husk (FMH) and barnyard millet husk (BMH) were characterized for their physical (extractive and density), chemical (X-ray photo spectroscopy and Fourier transform infrared spectroscopy), thermal (Thermo-gravimetric analysis), and morphological (X-ray diffraction and Scanning electron microscopy) behavior. The major objective was to explore their potential in the development of thermoplastic composites. Thermal kinetics of the fibers were studied with Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) models. After fiber characterization, the composites were developed using injection molding process and characterized for mechanical, thermal, and morphological behavior. In the end, the flammability properties of the developed composites were investigated with Thermo-gravimetric analysis, UL-94 Horizontal burning, and Limiting Oxygen Index testing. Chemical constituent analysis reveals higher cellulosic and lower lignin content of FMH (cellulose; 38.01% and lignin; 16.25%) than BMH (cellulose; 34.5% and lignin; 21.31%). Thermal kinetics shows higher activation energy (Ea) for BMH (207.17 kJ/mol) than FMH (129.82 kJ/mol) as per the FWO model. BMH reinforced composites offer higher thermal stability and flame resistance than FMH reinforced composites, while FMH reinforced composites show higher mechanical properties than BMH reinforced composites. Overall, both husks show the potential to be used in developing thermoplastic composites.
查看更多>>摘要：? 2022Global transition towards a bio-based economy to reduce the carbon footprints as an alternative to petroleum-based has led to the production of new cellulosic fibre-based eco-sustainable products in the construction and building industry. The present review gives an insight into how bio-based (fibre) is used as a reinforcement in polymer matrix composites. Specifics of the fibres in varied forms and their effect on the tensile characteristics of the resulting epoxy composites are reviewed. Studies reported to date have mostly focussed on improving the strength in the context of mechanical behaviour of the composites for varied structural applications. However, the scientific knowledge relating to modulus, its reinforcing capabilities are very limited in the literature. Detailed studies on the effect of dense regions with high moduli, less dense with insignificant moduli, point-to-point variation in the matrix are needed. This review proffers detailed explanations of the chemical treatments, hybridization, processing methods used from the last 22 years (2000–2022) in processing natural fibre composites (NFC) for value-added products. Future perspectives and functionalization of intelligence in biocomposites are also discussed.
查看更多>>摘要：? 2022 Elsevier B.V.This study was to evaluate the effects of microwave and conventional processing methods on the aroma profiles of fenugreek seeds and flours. The volatiles of raw, sprouted, boiled, roasted, and micro-waved fenugreek grains were evaluated using headspace-solid phase micro-extraction (HS-SPME) coupled to gas chromatography–mass spectrometry (GC-MS). 51 and 60 volatiles were detected in the emission bouquets of raw and processed seeds and flours, respectively. Volatiles were divided into seven chemical classes, including monoterpenes hydrocarbons, sesquiterpenes hydrocarbons, phenylpropanoids, non-terpenes derivatives, apocarotenes, nitrogen/sulfur derivative and oxygenated monoterpenes. The data showed that volatiles were significantly affected by the type of processing. All treatments increase the amounts of volatiles including aldehydes, alcohols, esters, and alkanes except for the microwave heating. Indeed, the dominant volatiles in microwaved fenugreek were pyrazines, with chocolate aroma like flavor. The microwave heating is based on an energy-efficient and water-saving technology; it is an interesting and more sustainable technique to be employed in the legume processing. The findings of this study demonstrate that microwave technology has potential for fenugreek processing.
查看更多>>摘要：? 2022The awareness of the environmental impact of CO2 emission from fossil fuels has resulted in the search for alternative renewable energy sources. Biomass-derived from agro-residues and economic trees have been identified as a sustainable fossil fuel alternative. The Leucaena leucocephala tree is abundant and presents diverse beneficial opportunities as a high-energy density tree. Its ability to thrive in harsh conditions and constituent nutrients render it valuable for biogas, bio-oil, biodiesel, ethanol, char, activated carbon, etc. production. In this review, an overview of the bioenergetic applications of the Leucaena leucocephala tree was discussed with emphasis on the challenges and potentials of production of biodiesel, bio-oil, ethanol, char, biogas, and activated carbon from the seeds, forages and leaves, bark, wood, and legumes of the Leucaena leucocephala. Also, the biorefinery concept was elucidated for the plausible generation of fine chemicals and fuels. It is hoped that this study will intensify research on the production of biofuels and fine chemicals from agro-industrial crops such as Leucaena leucocephala and its integration into biorefinery.
Garcia-Martinez M.M.Hurtado de Mendoza J.Jara F.M.Lopez-Corcoles H....
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查看更多>>摘要：? 2022 The AuthorsIn the rubber extraction process, guayule leaves represent an important biomass waste by-product, up to 32%, whose exploitation might contribute to the valorization of the whole plant. The extraction of any of its bioactive compounds or its use as an antioxidant seems to be the most feasible alternative. This study relates guayule leaves morphology to the individual content of 35 compounds (of the 50 tentatively identified), the determination of overall phenolic content and antioxidant activity. The morphological traits allowed the classification of the accessions (27) into three main groups according to size and shape of the leaf, being related to their hybridization. The environment and growing conditions modified the leaf phenotype for USDA germplasm with respect to recent USA studies. The heterogeneity found by different authors in the determination of phenolic content in guayule leaves requires a standardization procedure. Of the two analysis protocols, Total Polyphenol Index (TPI) and Folin–Ciocalteau reagent (Folin) after extracting the leaves at 1 and 24 h, the TPI at 1 h was selected since it was faster and simpler than others and correlated better with the antioxidant activity determined by 2,2-diphenyl-picrylhydrazyl (DPPH). The compounds found in greater quantities corresponded to the chlorogenic acid family, but with no influence with leaf morphology. On the other hand, compounds with smaller concentrations such as gallic acid, an isomer of ferulic acid or the quercetagetin methyl ether glucuronide correlate with aspects of leaf morphology.
查看更多>>摘要：? 2022 Elsevier B.V.Millettia Speciosa Champ (M. speciose) is an important medicinal plant applied for multiple disease treatments, however, the polysaccharide composition in M. speciose is rarely investigated. In this study, the structural features and immunomodulatory activities of a polysaccharide (MSCP1) from M. speciose were studied. Results suggested that MSCP1, with a molecular weight of 9.36 × 103 g/mol, consisted of glucose and xylose at a molar ratio of 1.31: 0.01. The glycosidic bond types and linkage manners were successfully elucidated by methylation and multi-dimensional nuclear magnetic resonance spectroscopy. The backbones of MSCP1 were composed of 1,4-linked-α-D-Glcp, 1,4-linked-α-D-Xylp and 1,4,6-linked-β-D-Glcp. The branch chain T-linked-α-D-Glcp was confirmed to be attached at C-6 of 1,4,6-linked-β-D-Glcp. An in vitro cell assay demonstrated that MSCP1 could prominently enhance the pinocytic activity and up-regulate the release of nitric oxide (NO) and cytokines in RAW 264.7 macrophages, implying a potent immunomodulatory activity. Overall, MSCP1 exhibits characteristics that qualify it as a promising candidate for immunologic adjuvant.
查看更多>>摘要：? 2022 Elsevier B.V.Trimethylolpropane fatty acid triester (TFATE) is a promising biolubricant as an environmentally friendly substitute to conventional mineral-based lubricants. However, the issues of extensive energy consumption from vacuum maintenance and feedstock saponification caused by strong alkaline catalysts exist in current TFATE-based biolubricant synthesis. Here, sustainable production of biolubricant was achieved with methyl oleate (MO) from non-edible oil sources as the feedstock and moderate alkaline K2CO3 as the catalyst. Nitrogen gas stripping method instead of vacuum was adopted for methanol removal. The effects of agitation speed, N2 flow rate, catalyst amount, MO to trimethylolpropane (TMP) molar ratio and temperature on MO conversion and TFATE selectivity were examined. The TFATE selectivity reached 95.6% under the optimized conditions. Leaching tests indicated neglectable K2CO3 dissolution in reaction products. The kinetic parameters for the three consecutive transesterification reactions were calculated. In addition, the synthesized biolubricants exhibit low acid value and volatility, moderate iodine value, superior thermal stability, and good rheological and frictional properties.
查看更多>>摘要：? 2022 Elsevier B.V.Although sulfomethylation (SM) and carboxymethylation (CM) have been used in the pretreatments of lignocelluloses, their effects on lignin structure of biomass and the interaction between lignin and cellulase remain unclear. In this work, alkaline pretreatment firstly removed 52.5% of lignin in sugarcane bagasse (SCB). The sequential SM and CM further increased the delignification capacities by 43.1% and 34.3%, respectively. Results of nuclear magnetic resonance, Fourier transform infrared spectroscopy and adsorption experiments show that the unites of ferulic acid and p-coumaric acid in residual lignin in alkaline-pretreated SCB (AP-SCB) were dissociated, and the -SO3- and carboxyl groups were introduced into the residual lignin in AP-SCB by SM and CM. The structural modification of residual lignin by SM and CM decreased the adsorption capacity of cellulase toward residual lignin in AP-SCB by 25.6% and 21.7%, resulting in the increase of glucose yield of AP-SCB from 52.2% to 83.8% and 73.6%, respectively. This work provides an efficient strategy to enhance sugars yields of alkaline-pretreated SCB through the mitigated nonproductive adsorption of residual lignin by SM and CM.
查看更多>>摘要：? 2022 Elsevier B.V.Pogostemon cablin Benth. contains abundance of patchoulol as one of the bioactive components. The present study demonstrated comprehensive optimizations of ultrasonic assisted extraction (UAE) and microwave assisted extraction (MAE) to achieve maximum lipid-soluble extract comprising highest patchoulol content by response surface methodology (RSM) followed by genetic algorithms (GA) approach. The extraction variables such as solute to solvent ratio (UAE, 10–30 g mL?1; MAE, 40–60 g mL?1), time (UAE, 10–20 min; MAE, 30–120 s) and sono-frequency (30–50 kHz) or microwave power (300–900 W) exerted significant influence on the yield and patchoulol content. RSM based optimizations for UAE resulted maximum yield of 182.24 mg/g of plant material consisting 48.84% patchoulol, while, yield 227.46 mg/g of plant material comprising 30.60% patchoulol were recorded under MAE. With the use of GA, the optimized values were further refined to obtain maximum yield of 207.87 mg/g of plant material comprising of 53.45% patchoulol under UAE, whereas, maximum 230.03 mg/g of plant material yield consisting of 31.71% patchoulol was achieved using MAE. UAE and MAE based kinetic modeling studies revealed involvement of more than one extraction mechanisms to achieve maximum yield and patchoulol (%). Further, higher extraction yield using MAE and UAE were also explained from the scanning electron microscopic (SEM) images, showing disintegration of matrix cell wall with numerous fractures leading to better dissolution of phytoconstituents in the extracting medium. Additionally, patchoulol content in the extract was significantly enhanced to 92.70% using silica gel. Patchoulol 92.70% and 53.45% containing extracts displayed excellent fungal mycelial inhibition against virulent strains of Aspergillus flavus (EC50 27.0–29.2 μg mL?1) and A. fumigatus (EC50 41.5–57.2 μg mL?1), respectively.
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