INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
·
IF 5.162
Yu Chen,Shidong Liu,Caiyan Wan,Guangxian Zhang
A novel flame retardant (FR), the ammonium salt of citrulline-penta (methylphosphonic acid) (ACPMPA) based on L-citrulline was synthesized, and its structure was characterized by 13 C, 1 H, and 31 P nuclear magnetic resonance (NMR) spectroscopy. The ACPMPA flame retardant molecule contains five ammonium salts of phosphorus acid and one ammonium salt of carboxylic acid, which allowed the covalent attachment of ACPMPA onto cellulose via -P=O(-O-C) and –COOC bonds. The results showed that the treated cotton fabrics had very high flame retardance and excellent durability. The limiting oxygen index (LOI) of cotton fabric treated with 35%-ACPMPA reached 49.2% and only decreased to 34.2% after 50 laundry cycles. Vertical flame tests also demonstrated that the treated cotton fabric acquired good flame retardance. The thermogravimetry (TG) and TG-IR results showed that the treated cotton left more residues and released almost no flammable volatiles at high temperatures. The cone calorimetry results showed that the treated cotton released less heat than pure cotton. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results demonstrated that the structure of the treated cotton fabric was almost unchanged, and no free formaldehyde was detected, indicating that the treated cotton was safe. The treated cotton fabric also retained good tensile strength and whiteness.
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Food Science and Technology
·
2020
·
IF 1.443
REN Haiwei,DU Nana,NIU Xiaoqian,WANG Yonggang,TIAN Hui,CAO Yingying,ZHANG Binyun,FAN Wenguang
Polyphenol oxidase is the popular enzyme involved in fruit-vegetable browning and melanin synthesis. In the present paper, L-3-phenyllactic acid, a natural bacteriostatic substance, was investigated as an inhibitor of polyphenol oxidase. The results were demonstrated that the residual enzyme activity of polyphenol oxidase decreased gradually with the increase of the concentration of L-3-phenyllactic acid. The L and ΔE values of the reaction system increased gradually. The reversible mixed-type inhibition mode of L-3-phenyllactic acid was determined by Lineweaver Burk plot. At the same time, the results of fluorescence quenching demonstrated that L-3-phenyllactic acid was a quencher of polyphenol oxidase, and the molecular docking study provided the binding mode of L-3-phenyllactic acid and polyphenol oxidase at the molecular level. L-3-phenyllactic acid decreased the activity of polyphenol oxidase and browning of fresh-cut Agaricus Bosporus. This research first studied the inhibitory effect of L-3-phenyllactic acid on the activity of polyphenol oxidase, and would provide a theoretical foundation for the use of L-3-phenyllactic acid as anti-polyphenol oxidase agents.
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MOLECULES
·
2020
·Vol. 25
·期 8
·1825
·
IF 3.267
Yuanyang Dong,Qihang Hou,Meng Sun,Jingjing Sun,Bingkun Zhang
Plantago asiaticaL. is widely distributed in Eastern Asia and a commonly used drug in China, Korea, and Japan for diuretic and antiphlogistic purposes. In this experiment, the present study was performed to isolate antioxidant molecules based on the DPPH scavenging activity assay and discover the bioactive compounds which contributed to performing the function ofPlantago asiaticaL. Each faction was chosen for further isolation guided by DPPH scavenging activity assay. Afterwards, two potential bioactive molecules, aesculetin and apigenin, were isolated for in vitro antioxidant activity in cells. Hydrogen-peroxide-induced oxidative stress led to decreased cell viability, impaired intercellular junction, and damage to the cell membrane and DNA. Furthermore, aesculetin ameliorated decreased cell viability induced by hydrogen peroxide via upregulation of antioxidant related genes, and apigenin also protected against H2O2mainly by improving the glutathione (GSH) antioxidant system, such as increasing the activity of glutathione peroxidase (GPX), glutathione reductase (GR), and the ration of GSH/glutathione disulfide (GSSG). Above all, these findings suggest that aesculetin and apigenin may be bioactive compounds for antioxidant function inPlantago asiaticaL.Keywords:antioxidants;compound isolation;DPPH;Plantago asiaticaL.;aesculetin;apigenin
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JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2020
·Vol. 97
·期 6
·603-614
·
IF 1.659
Jia Luo,Zeping Wang,Shangzhi Deng,Fan Zhang,Guirong Bao,Junni Mao,Wenjing Yang
Direct glycerolysis of novel edible Sacha Inchi ( Plukenetia volubilis L.) seed oil (PvLO) into diacylglycerols (DAG) and monoacylglycerols (MAG) was studied over solid Na 2 SiO 3 with or without microwave assistance. The glycerolysis yield was calculated by qualitative and semiquantitative analyses of 1 H NMR, 13 C NMR, and FT-IR spectra. The yields of ~33% 1, 3-DAG, ~16% 1, 2-DAG, ~40% 1-MAG, and ~2.3% 2-MAG were achieved after 16 hours at 120 °C in three consecutive cycles using acetone, with an interesterification rate of 92%. The modified oil showed enhanced gelation ability at low temperatures. The yield of 1, 2-DAG can be increased by adding acetone as solvent. The fatty acid compositions and unsaturated structure of lipids were less destroyed after alkaline glycerolysis. However, more α-linolenic and linoleic acids were transferred to the sn -2 position of glyceryl skeleton. The oxidative stability of the modified oil was still controllable. In summary, this work provides a feasible method to convert polyunsaturated plant oils into oils rich in DAG and MAG with less destructive impact on the olefinic structure of oil. Also, it provides a useful example of how to quickly evaluate the influence of chemical modification on the chemical structure of plant oils by using various spectral technologies.
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Food Science & Nutrition
·
2020
·Vol. 8
·期 8
·4121-4133
·
IF 1.797
Yiming Fang,Rui Li,Zhong Chu,Kexue Zhu,Fenglin Gu,Yanjun Zhang
This survey reports for the first time the changed of quality of fermented cocoa ( Theobroma cacao L.) beans. The quality evaluation and simultaneous detection of amino acids, flavor, procyanidin, color, fat, protein, antioxidant activity, and enthalpy were obtained for different fermentation stages of cocoa beans. The results showed that total essential amino acids contents ranged from 2.64 g/100 g to 3.68 g/100 g. A total of 88 compounds identified at the end of the fermentation belonged to alcohols, acids, esters, ketones, pyrazines, aldehydes, and terpenoids. One of the chemical groups that were present in highest abundance in the consummation treatments was acids, representing 56.04% of the total extracted area, followed by alcohols (22.95%) and ketones (9.40%). The colors of the beans in different fermentation stages were different, from deep purple to deep red-brown. Fermented cocoa beans were shown to be 53.45% and 13.51% bean butter and protein content, respectively. The value of denaturation enthalpy (Δ H ) ranged from 30.4 (J/g) to 43.38 (J/g). The 3-day fermented sample had the highest Δ H (43.38 J/g). When the fermentation process was complete, the procyanidin concentration of the beans decreased, with the final yield of procyanidin at 6.2%. During fermentation, the antioxidant capacity of beans gradually reduced. The fermenting of cocoa beans had a significant effect on the quality formation. The findings of this study constitute a basis for further investigations on the quality formation of cocoa during fermentation.
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Journal of Nanomaterials
·
2020
·
IF 1.98
Guoyong Wang,Chongxian He,Wengjing Yang,Fangwei Qi,Guowen Qian,Shuping Peng,Cijun Shuai
Graphene oxide (GO) usually serves as a reinforce phase in polymer because of its superior mechanical strength and high specific surface area. In this work, GO was grafted with L-lactic acid monomer (denoted as GO@PLLA) to overcome the aggregation in matrix and then incorporated into the poly-L-lactic acid (PLLA) scaffold fabricated by selective laser sintering. In hybrid scaffold, GO@PLLA exhibited uniform dispersion in the matrix. Furthermore, mechanical interlock between GO@PLLA and PLLA matrix formed and reinforced the interface bonding. On the other hand, the heterogeneous distributed GO acted as effective nucleating agent and resultantly enhanced the crystallization. Results showed that the tensile and compressive strength of scaffolds increased by 143.3% and 127.6%, respectively. Meanwhile, the scaffold exhibited an increased degradation rate of 37.9%, which could be attributed to the abundant hydrophilic functional groups on GO. Moreover, the scaffold exhibited favorable bioactivity and biocompatibility. Herein, the developed hybrid scaffold showed potential capacity for bone tissue engineering.
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GREEN CHEMISTRY
·
2020
·Vol. 22
·期 13
·4222-4230
·
IF 9.48
Jiayuan Yu,Anker Degn Jensen,Lei Wang,Chunshan Li,Suojiang Zhang
Methacrolein (MAL) is an important chemical for the manufacture of methyl methacrylate and a key monomer in many polymerization reactions. In this study, L-proline was investigated as the catalyst for the aldol condensation of formaldehyde and propionaldehyde to produce MAL. The catalytic activity of the reaction system was closely related to the competition between the main reaction synthesizing MAL and the side reaction producing 2-methyl-2-pentenal, which could be modified by adjusting the operating parameters. The influences of several operating conditions, including temperature, reaction time and water content, on the catalytic performance of the system were systematically studied via a series of single-factor experiments, and the optimized reaction conditions were obtained. The mechanistic investigation via ESI-MS indicated that the reaction pathway followed the Mannich route. Experimental and theoretical kinetic analyses of the L-proline-catalyzed aldol condensation reaction were performed, and the reaction orders of the reactants were obtained by regression. The results showed that L-proline was an efficient catalyst for the production of MAL via aldol condensation under mild conditions.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Guoguang Wei,Yan Chen,Ning Zhou,Qiuhao Lu,Sheng Xu,Alei Zhang,Kequan Chen,Pingkai Ouyang
Enzyme cofactors are essential in biocatalysis for many enzymes. However, their high commercial cost limits the industrial application of cofactor-dependent enzymes. We overcame this challenge by constructing a self-sufficient biocatalyst that co-immobilised pyridoxal 5′-phosphate (PLP) and L-lysine decarboxylase (LDC) using natural polymer chitin as the functional material. First, degree of deacetylation (DDA) of chitin was regulated to enhance PLP adsorption and immobilisation. Then, the enzyme was immobilised via fusion of a chitin-binding domain. Chitin with 36% DDA efficiently co-immobilised LDC and PLP. Laser scanning confocal microscope and scanning electron microscope proved that the LDC and PLP were immobilised on the chitin. The self-sufficient biocatalyst retained over 55% of its original activity after five cycles. The proposed strategy provides a new way to achieve co-immobilisation of PLP-dependent enzymes.
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Frontiers in Bioengineering and Biotechnology
·
2021
·
IF 5.89
Yang Chen,Liu Yushi,Liu Wan-Qiu,Wu Changzhu,Li Jian
Cell-free systems have been used to synthesize chemicals by reconstitution of in vitro expressed enzymes. However, coexpression of multiple enzymes to reconstitute long enzymatic pathways is often problematic due to resource limitation/competition (e.g., energy) in the one-pot cell-free reactions. To address this limitation, here we aim to design a modular, cell-free platform to construct long biosynthetic pathways for tunable synthesis of value-added aromatic compounds, using (S)-1-phenyl-1,2-ethanediol ((S)-PED) and 2-phenylethanol (2-PE) as models. Initially, all enzymes involved in the biosynthetic pathways were individually expressed by an E. coli-based cell-free protein synthesis (CFPS) system and their catalytic activities were confirmed. Then, three sets of enzymes were coexpressed in three cell-free modules and each with the ability to complete a partial pathway. Finally, the full biosynthetic pathways were reconstituted by mixing two related modules to synthesize (S)-PED and 2-PE, respectively. After optimization, the final conversion rates for (S)-PED and 2-PE reached 100 and 82.5%, respectively, based on the starting substrate of l-phenylalanine. We anticipate that the modular cell-free approach will make a possible efficient and high-yielding biosynthesis of value-added chemicals.
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Catalysis Science & Technology
·
2019
·Vol. 9
·期 21
·5943-5952
·
IF 5.726
Lian Xu,Li-Chao Wang,Xin-Qi Xu,Juan Lin
L-Threonine transaldolase (LTTA) is a putative serine hydroxymethyltransferase (SHMT) that can catalyze the trans-aldehyde reaction of L-threonine and aldehyde to produce L-threo-β-hydroxy-α-amino acids with excellent stereoselectivity. In the present study, an L-threonine transaldolase from Pseudomonas sp. (PsLTTA) was mined and expressed in Escherichia coli BL21 (DE3). A substrate spectrum assay indicated that PsLTTA only consumed L-threonine as the donor substrate and could accept a wide range of aromatic aldehydes as acceptor substrates. Among these substrates, PsLTTA could catalyze p-methylsulfonyl benzaldehyde and L-threonine to produce L-threo-p-methylsulfonylphenylserine with a high conversion rate (74.4%) and a high de value (79.9%). The conversion and stereoselectivity of PsLTTA were found to be dramatically influenced by the concentration of the whole cell, the co-solvent and the reaction temperature. Through conditional optimization, L-threo-p-methylsulfonylphenylserine was obtained with 67.1% conversion and a near-perfect de value (94.5%), the highest stereoselectivity for an L-threo-β-hydroxy-α-amino acid so far reported by enzymatic synthesis. Finally, synthesis of L-threo-p-methylsulfonylphenylserine at a 100 mL scale by whole-cell biocatalysis was conducted. This is the first systematic report of L-threonine transaldolase as a robust biocatalyst for preparation of β-hydroxy-α-amino acids, which can provide new insights for β-hydroxy-α-amino acids synthesis.
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JOURNAL OF FLUORESCENCE
·
2019
·Vol. 29
·期 4
·819-825
·
IF 1.913
Xu Yin-long,Bai Rong-biao,Qi Cai-yu,Ren Zeng,Jia Xiu-zhi,Kan Zi-gui,Li Cao-long,Wang Fei
Herein, a simple and efficient fluorescence analysis method for L-Cysteine (L-Cys) was established. The method was based on the fluorescent “off-on” mode of nitrogen doped carbon dots (NCDs). The NCDs were prepared via a facile one-step solvothermal method. In the process of exploring the bio-functional application of these newly synthesized NCDs, we found these NCDs with rich functional groups exhibited excellent optical properties. In addition, these newly synthesized NCDs showed an excitation-dependent emissions photolumine-scent (PL) property and exhibited good performance in the detection of Fe 3+ ions by quenching the blue emission fluorescence. Interestingly, the quenched fluorescence of NCDs was recovered with the addition of L-Cys, which provided a novel approach for L-Cys detection. The NCDs-based fluorescent “off-on” sensor has a wide linear detection range (0–100 μM), and a relatively low detection limits (0.35 μ M) for L-Cys. This simple fluorescent “off-on” approach is, very sensitive and selective for L-Cys detection, which also provides a new insight on NCDs biosensor application.
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RSC Advances
·
2019
·Vol. 9
·期 35
·20149-20160
·
IF 3.049
Dandan Chen,Qiang Chen,Tianyu Liu,Jian Kang,Ruizhang Xu,Ya Cao,Ming Xiang
To prepare polyamide thin-film composite reverse osmosis (PA-TFC-RO) membranes with high performance, L-arginine (Arg) was used as an additive in m-phenylenediamine (MPD) aqueous solution. Arg with active amine groups can react with 1,3,5-benzenetricarboxylic chloride (TMC) to be incorporated into the polyamide selective layer during interfacial polymerization. X-ray photoelectron spectroscopy verified the successful introduction of Arg into the polyamide selective layer. Scanning electron microscopy, atomic force microscopy, contact angle and zeta potential measurements manifested that the polyamide selective layer was thinner, smoother, more hydrophilic and less negatively charged after the incorporation of Arg. The thinner and more hydrophilic polyamide selective layers favor the boosting of the permeability of the RO membrane by decreasing the hydraulic resistance to water permeation. Consequently, when the content of Arg was 0.5 wt%, the water flux and salt rejection of the resulting membranes increased from the original 46.46 L m−2 h−1 and 96.34% to 54.13 L m−2 h−1 and 98.36%. Besides, the modified membranes showed excellent fouling-resistance and easy-cleaning properties when tested by using bovine serum albumin (BSA) and dodecyltrimethyl ammonium bromide (DTAB) as model foulants.
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