Keywords Host-guest cage structured; MNPs@ALG@SiO.sub.2 composite; Embedding immobilized enzyme; Degradation of TeCG Highlights * Cage structure of MNPs @ ALG@SiO.sub.2 as enzyme carrier was ...synthesized. * The synthetic cage structure has high performance for the degradation of tetrachloroguaiacol. * Optimized the conditions for the degradation of tetrachloroguaiacol by magnetic composite cage structure. * The degradation mechanism were studied in detail. Entrapment of enzyme in a cage structure of alginate/silica composite gel can maintain the chemical or configurational structures unchanged in the enzyme, providing a promising means of enzyme immobilization. The alginate/silica composite gel can also provide more adsorption sites for the substrate, which is biocompatible and will carry out degradation and adsorption of pollutants within a cage-like structure reactor simultaneously. In this study, we used a magnetic host-guest cage structured MNPs@ALG@SiO.sub.2 composite with a specific enzyme embedded as its guest in the host matrix, to enhance its performance. Additionally, its swelling, leakage rate and immobilization conditions were optimized. The magnetic nanoparticles (MNPs) were used to compensate for the ease of collapse of the internal structure of alginic acid, while SiO.sub.2 was used to enhance the swelling resistance of the carrier and prevent the degradation of polysaccharides in the natural environment, thereby maintaining the enzyme biological activity and immobilization rate. Finally, the effects on the degradation of tetrachloroguaiacol (TeCG) by the immobilized enzyme embedded in the MNPs@ALG@SiO.sub.2 composite were investigated. When the concentration of ALG was 2% and the TEOS concentration was 40 %, the immobilized MNPs@ALG@SiO.sub.2 was found to perform the best. The optimum conditions of immobilizing laccase are pH = 5, enzyme concentration 0.4 g/L, adsorption time 12 h and temperature 20 a. The degradation conditions of TeCG are pH = 6, degradation temperature 40 a, degradation time 10 h and the degradation products of TeCG were acetic acid and ethanol according to GC--MS. Author Affiliation: (a) School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai, 200237, China (b) State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology), Chengdu, 610059, China (c) Department of Materials Science and Engineering, University of Delaware, DE, 19716, USA (d) State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, 130012, China * Corresponding author at: School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai, 200237, China. Article History: Received 3 September 2020; Revised 9 December 2020; Accepted 30 December 2020 Byline: Jie Li (a), Yuxiang Yang yxyang@ecust.edu.cn (a,c), Zhiyong Han (b), Min Zhao (a), Hongming Yuan (d), Chaoying Ni cni@udel.edu (c)
The purpose of this work was to study the qualitative and quantitative composition of the main groups of biologically active substances in the fresh fruits of five different varieties of black ...chokeberry (Aronia melanocarpa (Michx.) Elliot), carried out within the framework of the search for available and cost-effective raw materials for food product fortification. Samples of aronia chokeberry were grown at the Federal Scientific Center named after I.V. Michurin in the Tambov region of Russia. Using a modern chemical-analytical methodology, the contents and profiles of anthocyanin pigments, proanthocyanidins, flavonoids, hydroxycinnamic acids, organic acids (malic, quinic, succinic, and citric), monosaccharides, disaccharides, and sorbitol were determined in detail. Based on the results of the study, the most promising varieties were determined in terms of the content of the main biologically active substances.
Haloxylon ammodendron and Haloxylon persicum, as typical desert plants in arid areas, show strong drought tolerance and environmental adaptability and are therefore ideal model plants for studying ...the molecular mechanisms of drought tolerance. A metabolomic analysis of H. ammodendron and H. persicum in their natural environment is lacking, and their metabolic response to drought therefore remains unclear. To elucidate the response of H. ammodendron and H. persicum to drought at the metabolic level, a non-targeted metabolomics analysis was carried out herein. Under a dry environment, H. ammodendron exhibited 296 and 252 differentially expressed metabolites (DEMs) in the positive and negative ion modes, respectively, whereas 452 and 354 DEMs were identified in the positive and negative ion modes in H. persicum, respectively. The results indicated that H. ammodendron responds to drought by increasing the content of organic nitrogen compounds and lignans, neolignans, and related compounds, and reducing the content of alkaloids and derivatives. By contrast, H. persicum adapts to the dry environment by increasing the content of organic acids and their derivatives and reducing the content of lignans, neolignans, and related compounds. In addition, H. ammodendron and H. persicum improved their osmoregulation ability, reactive oxygen species detoxification ability, and cell membrane stability by regulating the key metabolic pathways and anabolism of associated metabolites. This is the first metabolomics report on the response of H. ammodendron and H. persicum to drought in their natural environment, providing a foundation for the further study of their regulatory mechanisms under drought stress.
Solid-liquid extraction was investigated to obtain selected major plant nutrients (P, K, Ca, Mg) from biofuel ash using weak organic acids like salicylic acid, citric acid, and oxalic acid as ...sacrificial leaching agents. In this study, three organic acids were compared to determine the most effective leaching agent for maximizing the P, K, Ca, and Mg extraction from biofuel ash. The findings indicated that 0.1 M citric acid was the most efficient for plant nutrient recovery, with 81.9% of P recovered after 30 min, 82.4% of Ca, 76.8% of Mg, and 47.3% of K. after 120 min. The highest amount of K, with 59.3% was recovered after 180 min of extraction with 0.1 M oxalic acid. However, recovery of P–80.7% was lower, and much lower recovery of Ca–2.3%, and Mg–68.6% after 180 min of extraction with 0.1 M oxalic acid. The leachates were not contaminated with heavy metals, just 0.47 mg/L of Zn, 7.67 mg/L of Al, and 1.99 mg/L of Fe were detected after 180 min of extraction with 0.1 M oxalic acid. The formation of calcium oxalates after extraction with 0.1 M oxalic acid was seen by SEM-EDS. The findings indicated that to achieve the highest recovery of all beneficial nutrients (P, K, Ca, Mg) different extraction times and different extraction agents are required.
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•0.1 M citric acid showed the best recovery of beneficial nutrients from ash.•0.1 M citric acid can recover more than 80% of P and Ca from biofuel ash.•Amounts of leached heavy metals to filtrate were lower that limits of detection.
This study proposed a new facile route to rational creating oxygen-vacancy (Vo)-rich surface of Co.sub.3O.sub.4 nanosheets by acetic acid leaching. The acid leached Co.sub.3O.sub.4 nanosheets was ...very active in peroxymonosulfate (PMS) activation for degradation of atrazine (ATZ), 99.4% ATZ removal efficiency was achieved in Co.sub.3O.sub.4-a/PMS system within only 30 min with the reaction rate constant (k) = 0.17 min.sup.-1, which was much superior to that of commercial Co.sub.3O.sub.4 nanopowder (k = 0.01 min.sup.-1) and pristine Co.sub.3O.sub.4 nanosheets (k = 0.04 min.sup.-1). Radical quenching experiments and electron spin response (ESR) tests revealed the superoxide radical (O.sub.2.sup..-) and singlet oxygen (.sup.1O.sub.2) were the domain reactive oxygen radicals in the ATZ degradation process. This study provides a promising route to design Vo-rich metal oxides to activate PMS for refractory organic contaminants degradation.
Detection of sub-ppm acetic acid (CHsub.3COOH) is in demand for environmental gas monitoring. In this article, we propose a CHsub.3COOH gas sensor based on Snsub.3Osub.4 and reduced graphene oxide ...(RGO), where the assembly of Snsub.3Osub.4-RGO nanocomposites is dependent on the synthesis method. Three nanocomposites prepared by three different synthesis methods are investigated. The optimum assembly is by hydrothermal reactions of Snsup.4+ salts and pre-reduced RGO (designated as RS nanocomposite). Raman spectra verified the fingerprint of RGO in the synthesized RS nanocomposite. The Snsub.3Osub.4 planes of (111), (210), (130), (13¯2) are observed from the X-ray diffractogram, and its average crystallite size is 3.94 nm. X-ray photoelectron spectroscopy on Sn3d and O1s spectra confirm the stoichiometry of Snsub.3Osub.4 with Sn:O ratio = 0.76. Snsub.3Osub.4-RGO-RS exhibits the highest response of 74% and 4% at 2 and 0.3 ppm, respectively. The sensitivity within sub-ppm CHsub.3COOH is 64%/ppm. Its superior sensing performance is owing to the embedded and uniformly wrapped Snsub.3Osub.4 nanoparticles on RGO sheets. This allows a massive relative change in electron concentration at the Snsub.3Osub.4-RGO heterojunction during the on/off exposure of CHsub.3COOH. Additionally, the operation is performed at room temperature, possesses good repeatability, and consumes only ~4 µW, and is a step closer to the development of a commercial CHsub.3COOH sensor.
Keywords Photoelectrochemical; Aptamer; Nanocomposites; Sensor; Vibrio parahaemolyticus Highlights * A novel photoelectrochemical aptamer sensor was successfully constructed. * The work conditions of ...sensor based on rare-earth doped Bi.sub.2WO.sub.6 and Ag.sub.2S were optimized. * The aptamer sensor exhibited good detection specificity, stability and reproducibility. * This study provides a rapid detection method of Vibrio parahaemolyticus. In this work, layer-by-layer self-assembly method was used to construct the working electrode of the photoelectrochemical (PEC) aptamer sensor. Rare-earth doped Bi.sub.2WO.sub.6 (BWO-1) and Ag.sub.2S are combined as highly efficient photoactive material to reduce the recombination rate of electron-hole pairs and enhance the photocurrent responsiveness under visible light. The PEC aptamer sensor, with BWO-1 concentration of 12 mg/mL, AgNO.sub.3 concentration of 0.14 mol/L, ascorbic acid (AA) concentration of 0.13 mol/L, pH value of 7.4, aptamer concentration of 2 mumol/L, and incubation time of 50 min, had an optimal photocurrent responsiveness. The developed method showed a wide linear range from 3.2 x 10.sup.2 CFU/mL to 3.2 x 10.sup.8 CFU/mL. The detection limit was 40 CFU/mL. The constructed PEC aptamer sensor exhibited good detection specificity, stability and reproducibility for Vibrio parahaemolyticus and provided a simple, low-cost and rapid detection strategy for prevention and control of foodborne diseases. This method could be promising for the rapid detection of other food-borne pathogenic bacteria in the food. Author Affiliation: (a) Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034, China (b) Liaoning Key Lab for Aquatic Processing Quality and Safety, Dalian Polytechnic University, Dalian 116034, China * Corresponding authors at: Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034, China. Article History: Received 17 October 2020; Revised 10 February 2021; Accepted 1 March 2021 (footnote)1 Authors Yunxia and Liangliang are the co-first author, and they contribute equally. Byline: Yunxia Hou (a,1), Liangliang Zhu (a,1), Hongshun Hao beike1952@163.com (a,b,*), Zuowei Zhang (a), Chao Ding (a), Gongliang Zhang (b), Jingran Bi (b), Shuang Yan (a), Guishan Liu (a), Hongman Hou houhongman@dlpu.edu.cn (b,*)
A sensitive fluorescence strategy was constructed for the detection of alpha-glucosidase activity based on AgInZnS QDs. The AIZS QDs which were synthesized by hydrothermal method have a fluorescence ...emission wavelength of 554 nm. Ce.sup.4+ was able to oxidize p-phenylenediamine (PPD) to generate oxPPD, which can quench the fluorescence of AIZS QDs through dynamic quenching. When alpha-glucosidase was introduced into the system, L-ascorbic acid-2-O-alpha-D-glucopyranosyl (AAG) could be hydrolyzed to form ascorbic acid (AA), which can reduce Ce.sup.4+ and prevent the oxidation of PPD. Thus, the dynamic quenching process was blocked accompanying with the fluorescence recovery of AIZS QDs. The developed detection system for alpha-glucosidase displayed a good linear relationship between 0.01 and 0.16 U·mL.sup.-1 with a detection limit of 0.0073 U·mL.sup.-1. The sensing platform with high feasibility and anti-interference is a competitive alternative applied to alpha-glucosidase-related diagnostics.
Contradictions have been reported on the effect of organic solvents, especially toluene, on enzymatic ring-opening polymerization (eROP) of L-lactide. Studies have shown that log P, a common measure ...of hydrophilicity, affects enzyme activity. This study examines the effect of solvents with various log P values on the eROP of L-lactide, performed using Candida rugosa lipase (CRL). N,N-dimethylacetamide (DMA), 1,2-dimethoxybenzene, 1,4-dimethoxybenzene, diphenyl ether, and dodecane were used as the organic solvents. The eROP in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPFsub.6) was also conducted to compare its performance with the organic solvents. The results show that BMIMPFsub.6-mediated eROP gave better conversion and molecular weight than the organic solvent-mediated eROP. In this study, the effects of solvents hydrophilicity are discussed, including the possibility of hexafluorophosphate ion (PFsub.6sup.−) hydrolysis to occur.
