Facile synthesis of lignin-based Fe-MOF for fast adsorption of methyl orange.

To rapidly remove dyes from wastewater, iron-based metal-organic frameworks modified with phenolated lignin (NH2-MIL@L) were prepared by a one-step hydrothermal method. Analyses of the chemical structure and adsorption mechanism of the NH2-MIL@L proved the successful introduction of lignin and the enhancement of its adsorption sites. Compared with NH2-MIL-101-Fe without phenolated lignin, the modification with lignin increased the methyl orange (MO) adsorption rate of NH2-MIL@L. For the best adsorbent, NH2-MIL@L4, the MO adsorption efficiency in MO solution reached 95.09% within 5 min. NH2-MIL@L4 reached adsorption equilibrium within 90 min, exhibiting an MO adsorption capacity of 195.31 mg/g. The process followed pseudo-second-order kinetics and the Dubinin-Radushkevich model. MO adsorption efficiency of NH2-MIL@L4 was maintained at 89.87% after six adsorption-desorption cycles. In mixed solutions of MO and methylene blue (MB), NH2-MIL@L4 achieved an MO adsorption of 94.02% at 5 min and reached MO adsorption equilibrium within 15 min with an MO adsorption capacity of 438.6 mg/g, while the MB adsorption equilibrium was established at 90 min with an MB adsorption rate and capacity of 95.60% and 481.34 mg/g, respectively. NH2-MIL@L4 sustained its excellent adsorption efficiency after six adsorption-desorption cycles (91.2% for MO and 93.4% for MB). The process of MO adsorption by NH2-MIL@L4 followed the Temkin model and pseudo-second-order kinetics, while MB adsorption followed the Dubinin-Radushkevich model and pseudo-second-order kinetics. Electrostatic interactions, π-π interactions, hydrogen bonding, and synergistic interactions affected the MO adsorption process of NH2-MIL@L4.

Uptake, translocation, and biological impacts of micro(nano)plastics in terrestrial plants: Progress and prospects.

Micro(nano)plastics are emerging environmental contaminants of concern. The prevalence of micro(nano)plastics in soils has aroused increasing interest regarding their potential effects on soil biota including terrestrial plants. With the rapid increase in published studies on plant uptake and impacts of micro(nano)plastics, a review summarizing the current research progress and highlighting future needs is warranted. A growing body of evidence indicates that many terrestrial plants can potentially take up micro(nano)plastics via roots and translocate them to aboveground portions via the vascular system, primarily driven by the transpiration stream. Exposure to micro(nano)plastics can cause a variety of effects on the biometrical, biochemical, and physiological parameters of terrestrial plants, but the specific effects vary considerably as a function of plastic properties, plant species, and experimental conditions. The presence of micro(nano)plastics can also affect the bioavailability of other associated toxicants to terrestrial plants. Based on analysis of the available literature, this review identifies current knowledge gaps and suggests prospective lines for further research.

Predicting membrane fouling in a high solid AnMBR treating OFMSW leachate through a genetic algorithm and the optimization of a BP neural network model.

Anaerobic membrane bioreactors are a promising technology in the treatment of high-strength wastewater; however, unpredictable membrane fouling largely limits their scale-up application. This study, therefore, adopted a backpropagation neural network model to predict the membrane filtration performance in a submerged system, which treats leachate from the organic fraction of municipal solid waste. Duration time, water yield flow, influent COD, pH, bulk sludge concentration, and the ratio of ΔTMP to filtration time were selected as input variables to simulate membrane permeability. The membrane pressure slightly increased by 1.1 kPa within 62 days of operation. The results showed that the AnMBR membrane filtration performance was acceptable when treating OFMSW leachate under a flux of 6 L/(m2·h). The model results indicated that the sludge concentration largely determined the membrane fouling with a contribution of 33.8%. Given the local minimization problem in the BP neural network process, a genetic algorithm was introduced to optimize the simulation process, and the relative error of the results was reduced from 5.57% to 3.57%. Conclusively, the artificial neural network could be a useful tool for the prediction of an AnMBR that is so far under development.

Bioaccessibility of Metals in Soils at Typical Legacy Industrial Sites: In Vitro Evaluation Using Physiologically-Based Extraction.

Risk assessment of soil metal pollution based on total metal contents might give overestimates by neglecting the bioaccessibility of the pollutants to soil biota. Physiologically-based extraction tests (PBET) are in vitro methods for evaluation of bioaccessibility of soil pollutants. A total of 27 soil samples collected from four types of legacy industrial site representing metal smelting, lead-acid battery factories, chemical plants and steel plants were analyzed for the bioaccessibility of six potentially toxic metals using a PBET method. The metal pollutants at the industrial sites depended on the former industrial processes and emissions. The highest proportions of gastric phase and intestinal phase in these soil samples were 43.9% for Cd and 27% for Cu, respectively. Factors affecting metal bioaccessibility included type of industry and soil properties. The soils at a lead-acid battery factory showed relatively high bioaccessibility of Pb, Zn and Cd and those at the steel plant showed relatively low metal bioaccessibility. Soil organic matter and clay contents were positively related to metal bioaccessibility but soil pH and CEC showed negative relationships. Further studies are recommended to determine the speciation of the bioaccessible metals in these soils.

Quantification of Microplastics in Soils Using Accelerated Solvent Extraction: Comparison with a Visual Sorting Method.

Visual sorting is a method that is widely used in microplastic analysis, but it has limitation in the quantification of small-size microplastics. Accelerated solvent extraction (ASE) which frequently used in the analysis of organic contaminants in soils and sediments was used here for the microplastics quantification. A recovery experiment using different spiked polymeric microplastics separately indicates that ASE was useful in the extraction of low-density and low-melting point polymeric microplastics. High recoveries and low matrix effects were observed for the polyethylene, polypropylene and polystyrene microplastics. A further comparison between ASE and visual sorting was conducted for seven soils from agricultural land used for long-term mulching with plastic films. The results confirmed that ASE was capable of microplastics quantification for farmland soils and polyethylene film in the ASE extracts could be identified by Fourier transform infrared spectroscopy. Meanwhile, ASE conducted on small samples (3.0 g) gave results that showed close agreement with the visual sorting method.

Optimization and characterization of pullulan production by a newly isolated high-yielding strain Aureobasidium melanogenum.

Pullulan is an extracellular water-soluble polysaccharide with wide applications. In this study, we screened strains that could selectively produce high molecular weight pullulan for application in industrial pullulan production. A new fungus strain A4 was isolated from soil and identified as Aureobasidium melanogenum based on colony characteristics, morphology, and internally transcribed spacer analysis. Thin-layer chromatography, Fourier-transform infrared spectroscopy, and nuclear magnetic resonance analysis suggested that the dominant exopolysaccharide produced by this strain, which presented a molecular weight of 1.384 × 106 Dalton in in-gel permeation chromatography, was pullulan. The culture conditions for A. melanogenum A4 were optimized at 30 °C and 180 rpm: carbon source, 50 g/L maltose; initial pH 7; and 8 g/L Tween 80. Subsequently, batch fermentation was performed under the optimized conditions in a 5-L stirred-tank fermentor with a working volume of 3 L. The fermentation broth contained 303 g/L maltose, which produced 122.34 g/L pullulan with an average productivity of 1.0195 g/L/h and 82.32 g/L dry biomass within 120 h. The conversion efficiency of maltose to pullulan (Y%) and specific production rate (g/h/g dry cells) (Qs) reached 40.3% and 0.0251 g/L/g dry cells, respectively. The results showed strain A4 could be a good candidate for industrial production.

Biosynthesis of Natural Rubber: Current State and Perspectives.

Natural rubber is a kind of indispensable biopolymers with great use and strategic importance in human society. However, its production relies almost exclusively on rubber-producing plants Hevea brasiliensis, which have high requirements for growth conditions, and the mechanism of natural rubber biosynthesis remains largely unknown. In the past two decades, details of the rubber chain polymerization and proteins involved in natural rubber biosynthesis have been investigated intensively. Meanwhile, omics and other advanced biotechnologies bring new insight into rubber production and development of new rubber-producing plants. This review summarizes the achievements of the past two decades in understanding the biosynthesis of natural rubber, especially the massive information obtained from the omics analyses. Possibilities of natural rubber biosynthesis in vitro or in genetically engineered microorganisms are also discussed.

Rumen fluid fermentation for enhancement of hydrolysis and acidification of grass clipping.

Rumen fluid, formed in rumen of ruminants, includes a complex microbial population of bacteria, protozoa, fungi and archaea, and has high ability to degrade lignocellulosic biomass. In this study, rumen fluid was used to ferment grass clipping for enhancing the hydrolysis and acidification of organic matters. Results showed that strict anaerobic condition, higher grass clipping content and smaller particle size of grass clipping were beneficial to the hydrolysis and acidification of organics. The increase of SCOD and total VFA concentration respectively reached 24.9 and 10.2 g/L with a suitable grass clipping content of 5%, a particle size <0.150 mm, and a fermentation time of 48 h. The VFA production was mainly attributed to the degradation of cellulose and hemicellulose with a total solid reduction of 55.7%. Firmicutes and Fibrobacteres were the major contributors to the degradation of cellulose and hemicellulose. The activity of carboxymethyl cellulose enzyme (CMCase), cellobiase and xylanase reached 0.027, 0.176 and 0.180 U/ml, respectively. The rumen fluid microorganisms successfully enhanced the hydrolysis and acidification of grass clipping.

High-specificity synthesis of novel monomers by remodeled alcohol hydroxylase.

BACKGROUND: Diols are important monomers for the production of plastics and polyurethanes, which are widely used in our daily life. The medium-chain diols with one hydroxyl group at its subterminal end are able to confer more flexibility upon the synthesized materials. But unfortunately, this type of diols has not been synthesized so far. The strong need for advanced materials impelled us to develop a new strategy for the production of these novel diols. In this study, we use the remodeled P450BM3 for high-specificity production of 1,7-decanediol. RESULTS: The native P450BM3 was capable of converting medium-chain alcohols into corresponding α, ω1-, α, ω2- and α, ω3-diols, with each of them accounting for about one third of the total diols, but it exhibited a little or no activity on the short-chain alcohols. Greatly improved regiospecificity of alcohol hydroxylation was obtained by laboratory evolution of P450BM3. After substitution of 12 amino acid residues (J2-F87A), the ratio of 1,7-decanediol (ω-3 hydroxylation) to total decanediols increased to 86.8 % from 34.0 %. Structure modeling and site-directed mutagenesis demonstrated that the heme end residues such as Ala(78), Phe(87) and Arg(255) play a key role in controlling the regioselectivity of the alcohol hydroxylation, while the residues at the mouth of substrate binding site is not responsible for the regioselectivity. CONCLUSIONS: Herein we employ an engineered P450BM3 for the first time to enable the high-specificity biosynthesis of 1,7-decanediol, which is a promising monomer for the development of advanced materials. Several key amino acid residues that control the regioselectivity of alcohol hydroxylation were identified, providing some new insights into how to improve the regiospecificity of alcohol hydroxylation. This report not only provides a good strategy for the biosynthesis of 1,7-decanediol, but also gives a promising approach for the production of other useful diols.

Rumen microbes, enzymes, metabolisms, and application in lignocellulosic waste conversion - A comprehensive review.

The rumen of ruminants is a natural anaerobic fermentation system that efficiently degrades lignocellulosic biomass and mainly depends on synergistic interactions between multiple microbes and their secreted enzymes. Ruminal microbes have been employed as biomass waste converters and are receiving increasing attention because of their degradation performance. To explore the application of ruminal microbes and their secreted enzymes in biomass waste, a comprehensive understanding of these processes is required. Based on the degradation capacity and mechanism of ruminal microbes and their secreted lignocellulose enzymes, this review concentrates on elucidating the main enzymatic strategies that ruminal microbes use for lignocellulose degradation, focusing mainly on polysaccharide metabolism-related gene loci and cellulosomes. Hydrolysis, acidification, methanogenesis, interspecific H2 transfer, and urea cycling in ruminal metabolism are also discussed. Finally, we review the research progress on the conversion of biomass waste into biofuels (bioethanol, biohydrogen, and biomethane) and value-added chemicals (organic acids) by ruminal microbes. This review aims to provide new ideas and methods for ruminal microbe and enzyme applications, biomass waste conversion, and global energy shortage alleviation.

Insights into the influence of polystyrene microplastics on the bio-degradation behavior of tetrabromobisphenol A in soil.

Soil contamination by emerging pollutants tetrabromobisphenol A (TBBPA) and microplastics has become a global environmental issue in recent years. However, little is known about the effect of microplastics on degradation of TBBPA in soil, especially aged microplastics. In this study, the effect of aged polystyrene (PS) microplastics on the degradation of TBBPA in soil and the mechanisms were investigated. The results suggested that the aged microplastics exhibited a stronger inhibitory effect on the degradation of TBBPA in soil than the pristine microplastics, and the degradation efficiency of TBBPA decreased by 21.57% at the aged microplastic content of 1%. This might be related to the higher TBBPA adsorption capacity of aged microplastics compared to pristine microplastics. Aged microplastics strongly altered TBBPA-contaminated soil properties, reduced oxidoreductase activity and affected microbial community composition. The decrease in soil oxidoreductase activity and relative abundance of functional microorganisms (e.g., Bacillus, Pseudarthrobacter and Sphingomonas) caused by aged microplastics interfered with metabolic pathways of TBBPA. This study indicated the importance the risk assessment and soil remediation for TBBPA-contaminated soil with aged microplastics.

Degradable, anti-swelling, high-strength cellulosic hydrogels via salting-out and ionic coordination.

Cellulosic hydrogels are widely used in various applications, as they are natural raw materials and have excellent degradability. However, their poor mechanical properties restrict their practical application. This study presents a facile approach for fabricating cellulosic hydrogels with high strength by synergistically utilizing salting-out and ionic coordination, thereby inducing the collapse and aggregation of cellulose chains to form a cross-linked network structure. Cellulosic hydrogels are prepared by soaking cellulose in an Al2(SO4)3 solution, which is both strong (compressive strength of up to 16.99 MPa) and tough (compressive toughness of up to 2.86 MJ/m3). The prepared cellulosic hydrogels exhibit resistance to swelling in different solutions and good biodegradability in soil. The cellulosic hydrogels are incorporated into strain sensors for human-motion monitoring by introducing AgNWs. Thus, the study offers a promising, simple, and scalable approach for preparing strong, degradable, and anti-swelling hydrogels using common biomass resources with considerable potential for various applications.

Polyethylene microplastic modulates lettuce root exudates and induces oxidative damage under prolonged hydroponic exposure.

Root exudates are pivotal in plant stress responses, however, the impact of microplastics (MPs) on their release and characteristics remains poorly understood. This study delves into the effects of 0.05 % and 0.1 % (w/w) additions of polyethylene (PE) MPs on the growth and physiological properties of lettuce (Lactuca sativa L.) following 28 days of exposure. The release characteristics of root exudates were assessed using UV-vis and 3D-EEM. The results indicated that PE increased leaf number but did not significantly affect other agronomic traits or pigment contents. Notably, 0.05 % PE increased the total root length and surface area compared to the 0.1 % addition, while a non-significant trend towards decreased root activity was observed with PE MPs. PE MPs with 0.1 % addition notably reduced the DOC concentration in root exudates by 37.5 %, while 0.05 % PE had no impact on DOC and DON concentrations. PE addition increased the SUVA254, SUVA260, and SUVA280 values of root exudates, with the most pronounced effect seen in the 0.05 % PE treatment. This suggests an increase of aromaticity and hydrophobic components induced by PE addition. Fluorescence Regional Integration (FRI) analysis of 3D-EEM revealed that aromatic proteins (region I and II) were dominant in root exudates, with a slight increase in fulvic acid-like substances (region III) under 0.1 % PE addition. Moreover, prolonged PE exposure induced ROS damage in lettuce leaves, evidenced by a significant increase in content and production rate of O2·-. The decrease in CAT and POD activities may account for the lettuce's response to environmental stress, potentially surpassing its tolerance threshold or undergoing adaptive regulation. These findings underscore the potential risk of prolonged exposure to PE MPs on lettuce growth.

Lignin/sodium alginate hydrogel for efficient removal of methylene blue.

In this work, a class of bio-based hydrogels (LN-NH-SA hydrogel) were prepared from aminated lignin and sodium alginate. The physical and chemical properties of the LN-NH-SA hydrogel were fully characterized using field emission scanning electron microscopy, thermogravimetric analysis, fourier transform infrared spectroscopy, N2 adsorption-desorption isotherms, and other techniques. LN-NH-SA hydrogels were tested for the adsorption of dyes (methyl orange and methylene blue). The LN-NH-SA@3 hydrogel showed better adsorption efficiency for MB with a maximum adsorption capacity of 388.81 mg·g-1, a bio-based adsorbent with a high adsorption capacity. The adsorption process followed the pseudo-second-order model and fitted to the Freundlich isotherm equation. More importantly, LN-NH-SA@3 hydrogel maintained 87.64 % adsorption efficiency after 5 cycles. Overall, the proposed hydrogel with environmentally friendly and low cost is promising for the absorption of dye contamination.

Electrospun compliant heparinized elastic vascular graft for improving the patency after implantation.

The low patency rate after artificial blood vessel replacement is mainly due to the ineffective use of anticoagulant factors and the mismatch of mechanical compliance after transplantation. Electrospun nanofibers with biomimetic extracellular matrix three-dimensional structure and tunable mechanical strength are excellent carriers for heparin. In this work, we have designed and synthesized a series of biodegradable poly(ester-ether-urethane)ureas (BEPU), following compound with optimized constant concentration of heparin by homogeneous emulsion blending, then spun into the hybrid BEPU/heparin nanofibers tubular graft for replacing rats' abdominal aorta in situ for comprehensive performance evaluation. The results in vitro demonstrated that the electrospun L-PEUUH (LDI-based PEUU with heparin) vascular graft was of regular microstructure, optimum surface wettability, matched mechanical properties, reliable cytocompatibility, and strongest endothelialization in situ. Replacement of resected abdominal artery with the L-PEUUH vascular graft in rat showed that the graft was capable of homogeneous hybrid heparin and significantly promoted the stabilization of vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs), as well as stabilizing the blood microenvironment. This research demonstrates the L-PEUUH vascular graft with substantial patency, indicating their potential for injured vascular healing.

Enhancing thermal conductivity and chemical protection of bacterial cellulose/silver nanowires thin-film for high flexible electronic skin.

Silver nanowires (AgNWs) thin films have emerged as a promising next-generation flexible electronic device. However, the current AgNWs thin films are often plagued by high AgNWs-AgNWs contact resistance and poor long-term stability. Here, to enhance the AgNWs stability on the surface of bacterial cellulose (BC), a novel flexible high conductivity thin-film was prepared by spin-coating a layer of polyvinyl alcohol (PVA) on the BC/AgNWs (BA) film. Firstly, BC film with high uniformity to better fit the AgNWs was obtained. It is observed that inadequately protected AgNWs can be corroded when AgNWs together with PVA were attached to the BC surface (BAP film), Yet, a layer of PVA was spin-coated on the surface of BA film, the BC/AgNWs/spin-coated 0.5 % PVA (BASP) thin-film (10.1 µm) exhibits that the PVA interfacial protective layer effectively mitigated the intrinsic incompatibility of BC with AgNWs as well as external corrosion (Na2S for 3 h) and immobilization of AgNWs, thus having a low conductive sheet resistance of 0.42 Ω/sq., which was better than most of the AgNWs-containing conductive materials reported so far. In addition, the resistance of the BASP thin-film changed little after 10,000 bending cycles, and the conductivity remained stable over BC directly immersed in 0.5 % PVA/AgNWs. This "soft" conductive material can be used to manufacture a new generation of electronic skin.

Do microplastics affect sulfamethoxazole sorption in soil? Experiments on polymers, ionic strength and fulvic acid.

Microplastics (MPs) and sulfamethoxazole (SMX) are emerging contaminants that are ubiquitous in the soil environment. In this study, we investigated MPs polymer type and soil environmental factor effects on SMX adsorption behavior in the soil system. Our results showed that MPs dosage affected the soil particles' SMX adsorption rate and capacity (Qe). Adding 1 % polystyrene (PS) increased the SMX adsorption rate significantly. The value of K1, which represented the adsorption rate, increased from 0.569 h-1 to 1.019 h-1. However, the addition of MPs reduced the soil's SMX equilibrium adsorption capacity slightly. Moreover, increasing salinity strength enhanced SMX adsorption capacity by MPs significantly. However, increasing calcium ions concentration decreased SMX adsorption in the MPs amended soil due to multivalent cationic bridging and competitive adsorption mechanisms. In addition, we observed that fulvic acid addition inhibited SMX adsorption. This study suggests that the addition of MPs reduced the adsorption of SMX in the soil slightly due to dilution effect. Meanwhile, changes in environmental factors also affected the adsorption behavior of SMX in soil amended with MPs.

Macro- and microplastic leachates show a slightly toxic effect on seed germination of cotton.

Utilizing degradable mulching film effectively decreases the accumulation of plastic residuals in agriculture fields and their impacts on plant growth. However, the chemical risks to plants raised by leached substances from different microplastics are still unknown. This work determined the characteristics of macro- and microplastic leachates from different degradation (PE, PO, and Bio) and size (1 × 1 cm, 450-600 µm and <355 µm), as well as their impact on the germination of two varieties of cotton seeds. Our study revealed that degradable characteristics of macro-plastic significantly affect its leachates. Leachates of Bio gained higher dissolved organic carbon (DOC) concentration, aromatic, and values of slope ratios (SR) compared with PO and PE. The particle size of Bio macro- and microplastics also influences indicators such as SR, E250/E365, E253/E203, and Fmax value; however, fluctuations of those indicators were significantly lower than that induced by different degradable traits. Leachates of PE, PO, and Bio seem to have little impact on the germination of two varieties of cotton seeds, only mean germination time (MGT) and shoot height were slightly different among each treatment. A slight fluctuation of enzyme activities also indicates that plastic leachate did not generate excessive oxidative stress in cotton during germination. Leachates of macro- and microplastic under the tested concentration exhibited a slight toxic impact on cotton, which has high-stress tolerance. Thus, further studies should concentrate on the effects of plastic leachate on sensitive plants.

Self-healing, EMI shielding, and antibacterial properties of recyclable cellulose liquid metal hydrogel sensor.

Flexible hydrogels are promising materials for the preparation of artificial intelligence electronics and wearable devices. Introducing a rigid conductive material into the hydrogels can improve their electrical conductivities. However, it may have poor interfacial compatibility with the flexible hydrogel matrix. Therefore, we prepared a hydrogel containing flexible and highly ductile liquid metal (LM). The hydrogel can be used as a strain sensor to monitor human motion. The hydrogel showed many properties (i.e., recyclability, EMI shielding properties (33.14 dB), antibacterial (100 %), strain sensitivity (gauge factor = 2.92), and self-healing) that cannot be achieved simultaneously by a single hydrogel. Furthermore, the recycling of LM and their application to hydrogel-based EMI shielding materials have not been investigated previously. Due to its excellent properties, the prepared flexible hydrogel has great potential for applications in artificial intelligence, personal healthcare, and wearable devices.

[Effects of Low-density Polyethylene Microplastics on the Growth and Physiology Characteristics of Ipomoea aquatica Forsk].

Microplastic pollution in soil and its toxicological effects have attracted increasing attention from researchers, but the mechanisms of microplastics affecting crop growth and physiology remain unclear. A pot experiment was conducted to evaluate the impacts of various mass concentrations (0%, 0.2%, 5%, and 10%) of low-density polyethylene microplastics (LDPE MPs) on the germination rate, photosynthetic pigment content, biomass, antioxidant enzyme activity, soluble protein, and soluble sugar content of water spinach (Ipomoea aquatica Forsk). The results showed that LDPE MPs significantly inhibited (P<0.05) the seed vigor of water spinach, and the inhibitory effect increased with increasing concentration of LDPE MPs. However, the 5% LDPE MPs significantly promoted the aboveground biomass of water spinach. The 0.2% and 10% LDPE MPs significantly improved the superoxide dismutase (SOD) activity and catalase (CAT) and peroxidase (POD) activities, respectively. Further, malondialdehyde (MDA) content decreased with increasing concentration of LDPE MPs, and the reductions reached 15.53%-27.39% in comparison to that in the control. The LDPE MPs also significantly increased the soluble sugar content of water spinach leaves. In summary, LDPE MPs could inhibit the seed vigor and promote biomass accumulation in water spinach. Water spinach could relieve the oxidative stress caused by LDPE MPs by regulating antioxidant enzyme activity and soluble protein content. Therefore, this study may provide basic information for assessing the influences of microplastics on vegetables.