查看更多>>摘要：Nowadays, biomass-derived monomers production and thermosets' recyclability are the two main efforts in the development of sustainable thermosetting epoxy resins to replace fossil derivatives and mitigate landfill build-up and ecological impact. Here, we propose a simple step and benign synthesis strategy by using the itaconic acid (IA) and two epoxidized vegetable oils (EVOs), linseed and soybean, in order to obtain fully bio-based materials with high carbon bio-content. The reactivity of these formulations, together with the properties of obtained thermosets were investigated and compared with that of DGEBA/IA homologous system. The EVOs/IA reactive mixtures show high reactivity, tested by differential scanning calorimetry (DSC) and Fourier-transformed infrared spectroscopy (FT-IR) while the obtained resins display good mechanical properties, high thermal stability as well as resistance to solvents. Due to the transesterification reaction in the polyester-based networks, recycling abilities tested both mechanically and chemically were proven. The fully reprocessed bio-based thermosets displayed almost unchanged thermomechanical properties and chemical structure combined with a simple and green chemical processing.
查看更多>>摘要：Duckweeds contain high levels of starch and are environmentally sustainable and economically viable feedstock for biofuel production. Here, the biomass and starch yield of three duckweed species under three different nutrient-limited conditions were analyzed to investigate the possible ways of further increasing the efficiency of starch production. The results showed that sulfur limitation resulted in the highest starch yield, which was 42% and 73% higher than in nitrogen or phosphorus limitation conditions, respectively. The high yield of sulfurlimited duckweed is largely due to the combinations of little effects on biomass and high accumulations of starch. Although nitrogen limitation led to higher starch content (67.4%), it severely reduced biomass production. Besides, this work revealed the mechanism of starch accumulation induced by sulfur limitation in duckweed based on transcriptomic analysis. In summary, sulfur limitation is a practical approach to increase starch yields in duckweed without affecting growth or biomass production.
查看更多>>摘要：Deep eutectic solvent (DES) is proved to be versatile for ramie fiber isolation due to its high degumming efficiency and feasible recycling process. However, ramie cellulose is easily to be chemically degraded during the intense reaction if the treatment conditions cannot be properly controlled, affecting the mechanical properties of ramie fibers. In this paper, anthraquinone (AQ), serving as effective cellulose protection agent, was applied in the process of DES degumming to enhance the properties of treated fibers. Under the addition of 0.2 g/L AQ, there was an increase of 3.2% in the degree of polymerization and 5.56% in the crystallinity. Besides, the breaking tenacity, breaking elongation, and work of rupture of degummed fibers increased by 8.44%, 11.94%, and 33.33%, respectively. The chemical structure and thermal properties were also analyzed and compared between degummed fibers with or without cellulose protection agent. It is found that a small amount of AQ could improve the degradation temperature of fibers, accelerate the removal of lignin, and protect carbohydrates from excessive degradation. Considering these significant advantages, intrinsic greenness of DES, as well as the auxiliary effect and inexpensiveness of AQ, this new degumming method holds enormous potential for natural fiber extraction.
Wang, ZhikangLeite, Marcio F. A.Xu, ZihengLin, Quan...
11页
查看更多>>摘要：Introducing probiotics to soil is a sustainable way to stimulate the production of plant metabolites. However, the soil-resident microbes may compromise the efficiency of probiotics. To date, it remains challenging to integrate the effects of probiotics on plant performance with soil microbiome changes. Using Cyclocarya paliurus (Batal.) Iljinsk as a model medicinal plant and two types of probiotic consortia combined with organic fertilizer at three levels (low: 0.5, medium: 1.0, and high: 1.5 kg center dot plant & xe213; 1), we examined the impacts of three fertilization regimes (O: organic fertilizer, OMF: O coupled with Bacillus megaterium and Pseudomonas fluorescens, OCB: O coupled with Azotobacter chroococcum and Azospirillum brasilense) on plant metabolites and nutrient stoichiometry after three-year applications and identified the key soil microbes relating to the accumulation of plant metabolites via generalized joint attribute model (GJAM) analysis. Our results indicated that the concentration of flavonoids reached 36.9 mg center dot g & xe213; 1 in OCB treatment at a low level, and 30.0 mg center dot g & xe213; 1 in OMF treatment at a medium level, both were significantly higher than that in O treatment (25.8 mg center dot g & xe213; 1 on average). Furthermore, the accumulations of metabolites were associated with plant nutrient acquisition and C: N: P stoichiometry. GJAM analysis showed that higher fertilizer levels restricted the influence of probiotic consortia on the variance of plant-soil-microbe system, with fewer differences observed between fertilizer types. Specific soil microbes were predicted as potential indicators that may assist or impede the effects of probiotics on plant metabolite production. The predictions were further tested in a comparative pot experiment, and the effects of common indicators in both pot and field experiments were consistently associated with probiotics' addition. This study reveals that the effects of probiotics on plant metabolites are associated with fertilization regimes and soil-indigenous microbes. Identifying microbial indicators will help to understand the probiotics' effects and further improve plant productivity.
查看更多>>摘要：Lignocellulosic biomass is a crucial agricultural and industrial product. Dilute acid pretreatment is a common step to break down the dense and complex lignocellulose-based structure of straw to enhance its biochemical conversion efficiency. The straw derived from diverse crops, such as corn, cotton, and rape, displays diverse internal morphologies and varying responses to pretreatment methods. It is, therefore, necessary to understand the underlying mechanisms of these microstructural changes, to maximize their industrial value. This is the first study to demonstrate X-ray micro-computed tomography (micro-CT) based 3D visualization to observe the changes in the histology of straw caused by pretreatment using dilute acids, understand the mechanism of dilute sulfuric acid pretreatment, and visualize the reason behind the resulting morphological changes in the microstructure of straw. Three types of straw from corn, cotton, and rape were treated with 1.5% (w/w) dilute sulfuric acid at 121 degrees C for 30 and 60 min. Subsequently, the straw samples were imaged using Skyscan1275 under optimized micro-CT scan and image reconstruction conditions. In addition, the algorithms for image segmentation were determined. Volume- and slice-rendered images were analyzed via pseudo-color processing for different straw samples. Furthermore, the results of the micro-CT 3D in situ visualization aligned with the chemical analysis of lignocellulose composition. Overall, the presented non-invasive 3D micro-CT technique can provide crucial insights into the morphology and thus microstructural changes of lignocellulose-based materials not only qualitatively, but also semi-quantitatively. The non-invasive imaging methodology described in the present study will prove to be extremely helpful in prompt in situ analysis and comparison of diverse treatment approaches using lignocellulosic biomass.
Onukwuli, O. DominicEzeh, M. ErnestEze, I. OchiaghaOdimegwu, N. Euphresia...
10页
查看更多>>摘要：This research examined the effect of selected chemical treatment on Banana fibre. The morphological, mechanical and chemical properties effects were investigated using the Scanning electron microscope, computerized Tensile machine and FTIR Instrument. The chemicals applied in fibre treatment were Alkali (NaOH), Permanganate (KmnO(4)), and Acetylation. The results obtained showed that the surface roughness of the fibres was increased, and the hydrophilic nature of the fibres was reduced. There was a void introduction on the surface of the fibre thereby providing better mechanical locking properties and reduction of water absorption tendency. The results of FT-IR spectroscopy showed gradual changes consistent with the removal of pectin, lignin, Hemicelluloses, oil, and waxes as chemical treatment time increased by comparing the changes in the intensity of the carbonyl-H, OH, C=C- H, C-H and C=O stretch. It also showed that the number of hydroxyl groups on the fibre surface decreased as treatment time increased. Alkali chemical surface modification treatment of fibres enhanced the properties of the fibres by disrupting hydrogen bonding in their network structure. Permanganate chemical handling accounted for the formation of cellulose radicals with MnO-3 ion formation and fibre surface modification treatment using acetic acid enhanced the reduction of the hygroscopic nature of the banana fibres leading to increased dimensional stability. Mostly, the alpha cellulose contents of the fibre were increased from 63.40% to 82.23% at Silane chemical handling, while the other major components were reduced comparatively. Mechanical properties of the fibres such as tensile strength, flexural modulus, and percentage elongation increased after chemical treatment. There was an increased loss in weight of fibres with increased chemical modification time which enhanced the mechanical properties of fibre strands.
查看更多>>摘要：Climate change requires the introduction of crop production technologies that guarantee stable yields under exposure to extreme weather events. The main focus should be on the reliability of yields, even if it implies a reduction in agricultural outputs. In the theory and practice of industrial experiments, Taguchi methods have been deployed to identify production technologies that are most resilient to the random effects of uncontrollable disrupting production factors. This is the first ever study where the Taguchi method was deployed in an agricultural field experiment to identify the levels of two fundamental production factors (genotype and planting density) that were most effective in stabilizing willow (Salix spp. L) biomass yields under variable uncontrollable abiotic and biotic stresses in annual harvest rotation. The analysis was based on the results noted in the first 12 consecutive years of a long-term field experiment in northern Poland. The results of the analysis involving the Taguchi method were validated under field conditions, and they were logical and consistent with the results of statistical analyses that are widely applied in this type of research. Uncontrollable stressors significantly influenced the levels of the least resilient production factors that were identified by the Taguchi method. The research assumptions were validated, which suggests that the Taguchi method could be considered in field experiments.
Yang, Yan HuiYang, Mu RongChen, Jia YiLiu, Zheng Yang...
14页
查看更多>>摘要：Acteoside and flavonoids as important natural products have pharmacological activities in Rehmannia glutinosa Libosch., which is of great economic significance for leading to efforts to enhance the productions. Coumarate: coenzyme A (CoA) ligases (4CLs) in higher plants could play pivotal roles in branching points at which the metabolic fluxes are directed to either the acteoside or flavonoids biosynthetic pathways. To investigate the molecular regulation in acteoside and flavonoids biosynthesis, the study identified and characterized two Rehmannia glutinosa 4CL genes (Rg4CL1 and Rg4CL2) by in silico and experimental analysis, revealing a 53.35-81.68 % protein sequence identity with equivalents from other plants, two highly conserved sequence motifs and subcellular localization to the cytosol. Phylogenetic and enzyme kinetic analyses indicated that Rg4CL1 belonged to Class I of this enzyme family, and was the highest activity towards caffeic acid, while Rg4CL2 grouped with Class II and efficiently catalyzed p-coumaric acid and cinnamic acid. The overexpression of Rg4CL1 and Rg4CL2 in Rehmannia glutinosa significantly increased acteoside and flavonoids productions, especially the acteoside accumulation from the Rg4CL1 overexpression lines and flavonoids accumulation from the Rg4CL2 overexpression lines. The results revealed that the Rg4CLs are involved in acteoside and flavonoids biosynthesis, especially, Rg4CL1 and Rg4CL2 may preferentially be responsible for the flux diversions towards acteoside and flavonoids biosynthesis, respectively. The study is the first to elucidate the molecular function of the Rg4CL isoforms in the biosynthetic pathways of acteoside and flavonoids, providing insights into the increase of natural active products from the phenylpropanoid pathway in Rehmannia glutinosa.
查看更多>>摘要：In this study, bacterial cellulose (BC) with antimicrobial properties was produced from waste jasmine flower through sequential fermentations with the fungus Trichoderma reesei and the bacterium Taonella mepensis. In this process, waste jasmine flower was first used for producing cellulase and xylanase with Trichoderma reesei. The activities of cellulase and xylanase in waste jasmine flower reached 66.54 U/g and 107.25 U/g, respectively. Waste jasmine flower was hydrolyzed enzymatically on-site and the resulting hydrolysate was used for BC production. The highest BC yield from supplemented jasmine flower hydrolysate (SJFH) was 4.78 g/L, 2.1 times higher than that from Hestrin and Schramm (HS) medium. BC samples were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, field emission scanning electron microscopy, and antibacterial analysis. The results showed that both the nano structure and thermal property of BC from SJFH medium (BC-JF) were similar to those of BC from HS medium (BC-HS). Furthermore, BC-JF composite displayed excellent antibacterial activity against Staphylococcus aureus. Considering the good biocompatibility of BC-JF to human umbilic vein endothelial cells, this antibacterial BC-JF, which was bioconverted from waste jasmine flower, shows great medical and pharmaceutical application potential.
查看更多>>摘要：Wood products are widely used in furniture and building materials, but the adhesives used to bond wood components are mainly formaldehyde-based resins, which are toxic, and most of their raw materials come from non-renewable resources. Replacing aldehyde-based adhesives with renewable materials is challenging for the development of wood-based panels. Here, we designed an aldehyde-free multifunctional adhesive with a rigid structure based on lignin and phytogenic protein. To enhance the defects of current phytogenic protein adhesives, as their poor water resistance and vulnerability to microbial erosion, this paper used phytogenic protein to regulate lignin and synthesized a triblock copolymer of three kinds of agricultural and forestry wastes, including lignin, camellia meal, and soybean meal, and finally made it form a densely cross-linked structure. This covalent crosslinking and block copolymerization strategy endowed the adhesive with a bonding strength of 1.03 MPa, which is comparable to that of commercial adhesives. It also showed good inherent mildew resistance, and its performance was better than previously reported adhesives that used chemical preservatives. This efficient, environmentally friendly, and low-cost design strategy can be used to convert low-cost natural biomass resources into high-value green products to alleviate environmental pollution and energy concerns associated with the use of petroleum-based materials.
NSTL
Elsevier