Systems Microbiology and Biomanufacturing
·
2023
·
IF 0
Sun Tingting,Liu Di,Zhang Linmeng,Fan Taiping,Cai Yujie
(2R,3R)-BDO is an important bio-based four-carbon platform compound and widely used in chemical, food, pharmaceutical, fuel and aerospace fields . Serratia marcescens has been shown to be an effective strain for producing BDO. However, there have been few reports on the metabolic engineering of this strain to efficiently produce (2R,3R)-BDO using xylose. In this study, the endogenous strong promoter was screened and modified, and combined with the screened RBS. (2R,3R)-BDO was successfully produced by combining the selected promoters and RBS with the overexpressed key enzymes (ALS, ALSD, BDH, GLF) of (2R,3R)-BDO production. The optimum fermentation temperature and pH were 37 ℃ and 6.0, respectively, and the optimized yield reached 6.0 g/L. After batch fermentation, the (2R,3R)-BDO yield reached 36.6 g/L. This provided a good idea for efficient production of (2R,3R)-BDO from xylose.
研究领域:
生物工程
·
微生物学
·
生物化学
✓ 已验证
DOI
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Yijian Liang,Haohui Ou,Benxuan Li,Wenjing Zhang
Bilayer (BL) two-dimensional transition metal dichalcogenides (TMDs) exhibit excellent properties in carrier mobility , state density, and room temperature stability, which attract considerable attention. However, previous efforts on synthesis BL TMDs have lacked homogeneity and control over the number of layers. Here, we demonstrate an effective and controllable approach to synthesize highly uniform 3R phase BL MoS 2 on a c-plane sapphire substrate . The number of MoS 2 layer can be controlled by adjusting the confinement distance, sapphire step height (annealing temperature), and growth temperature. These influencing factors have been thoroughly investigated. Raman and PL analyses demonstrate bilayer properties and remarkable uniformity. SHG and HAADF-STEM measurements reveal 3R stacking structure of BL MoS 2 . Furthermore, field-effect-transistor (FET) devices fabricated using BL MoS 2 domains exhibit high carrier mobility and on/off ratio. This work provides an efficient method for layer-controlled MoS 2 growth and offers new insights into the growth mechanism of BL MoS 2 .
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2023
·Vol. 24
·期 18
·14220
·
IF 5.6
Yaping Xu,Zhengwen Li,Yue Wang,Chujie Li,Ming Zhang,Haiming Chen,Wenxue Chen,Qiuping Zhong,Jianfei Pei,Weijun Chen,Guido R. M. M. Haenen,Mohamed Moalin
It has been reported that in an oxidative environment, the flavonoid2R,3R-dihydroquercetin (2R,3R-DHQ) oxidizes into a product that rearranges to form quercetin. As quercetin is a very potent antioxidant, much better than2R,3R-DHQ, this would be an intriguing form of targeting the antioxidant quercetin. The aim of the present study is to further elaborate on this targeting. We can confirm the previous observation that2R,3R-DHQ is oxidized by horseradish peroxidase (HRP), with H2O2as the oxidant. However, HPLC analysis revealed that no quercetin was formed, but instead an unstable oxidation product. The inclusion of glutathione (GSH) during the oxidation process resulted in the formation of a2R,3R-DHQ-GSH adduct, as was identified using HPLC with IT-TOF/MS detection. GSH adducts appeared on the B-ring of the2R,3R-DHQ quinone, indicating that during oxidation, the B-ring is oxidized from a catechol to form a quinone group. Ascorbate could reduce the quinone back to2R,3R-DHQ. No2S,3R-DHQ was detected after the reduction by ascorbate, indicating that a possible epimerization of2R,3R-DHQ quinone to2S,3R-DHQ quinone does not occur. The fact that no epimerization of the oxidized product of2R,3R-DHQ is observed, and that GSH adducts the oxidized product of2R,3R-DHQ on the B-ring, led us to conclude that the redox-modulating activity of2R,3R-DHQ quinone resides in its B-ring. This could be confirmed by chemical calculation. Apparently, the administration of2R,3R-DHQ in an oxidative environment does not result in ‘biotargeting’ quercetin.Keywords:2R,3R-dihydroquercetin;redox modulation;quercetin;quinone;epimerization
研究领域:
生物化学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOORGANIC CHEMISTRY
·
2021
·
IF 5.275
Lian Xu,Li-Chao Wang,Bing-Mei Su,Xin-Qi Xu,Juan Lin
(2 S , 3 R )-4-methylsulfonylphenylserine [(2 S , 3 R )-MPS], a key chiral precursor for antibiotics florfenicol and thiamphenicol, could be asymmetrically synthesized by l -threonine transaldolase (LTTA) coupled with an acetaldehyde elimination system. The low efficiency of acetaldehyde elimination system blocked further accumulation of (2 S , 3 R )-MPS. To address this issue, strengthening acetaldehyde elimination system and enzyme self-assembly strategy were combined to accelerate biosynthesis of (2 S , 3 R )-MPS. The new multi-enzyme cascade with intensified acetaldehyde elimination system BL21 (PsLTTAD2/ScADH/BtGDH) could produce (2 S , 3 R )-MPS with a titer of 157.6 mM, 1.7-folds than that produced by the original system BL21 (PsLTTAD2/ApADH/CbFDH). Moreover, self-assembly of PsLTTAD2 and ScADH by respective fusion of SpyTag and SpyCatcher were carried out to develop a self-assembled multi-enzyme cascade BL21 (ST-PsLTTAD2/SC-ScADH/BtGDH). As a result, the yield of (2 S , 3 R )-MPS was up to 248.1 mM with 95% de . As far as we knew, that represented the highest yield of (2 S , 3 R )-MPS by enzymatic synthesis, and therefore was a promising and green route for industrial production of this valuable compound.
研究领域:
生物催化
·
酶工程
·
生物技术
·
化学生物学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2025
·
IF 9.7
Yan Gao,Shuhan Lu,Xiongpo Hou,Bin Wang,Zhao Jiang,Yuqi Wang,Tao Fang
Compared to hexagonal 2H-MoS 2 , rhombohedral 3R-MoS 2 exhibits noncentrosymmetric atomic structures and enhanced current density and carrier mobility. Rhombohedral 3R-MoS 2 is considered to possess outstanding electrocatalytic properties comparable to those of 1 T-MoS 2 . However, the preparation of 3R-MoS 2 has been rarely reported owing to its metastable nature and high formation energy. Herein, we perform theoretical calculations to demonstrate that Na adsorption in MoS 2 interlayers can alter the arrangement of adjacent layers. Based on this finding, and assisted by Na 2 SO 4 , a bottom-up synthesis strategy is designed for the in-situ growth of 3R-MoS 2 . In-situ Raman spectroscopy confirms that the electronic configuration of Mo is regulated by the insertion of Na into the MoO 3−x lattice, which is facilitated by high-temperature diffusion, thereby guiding the epitaxial growth of 3R-MoS 2 . As hydrogen evolution reaction catalysts, 3R-MoS 2 exhibits an overpotential of 51.4 mV and a Tafel slope of 35.6 mV/dec. Further analyses indicate that this excellent performance can be attributed to the intrinsic activity of 3R-MoS 2 . Additionally, obtaining a product with perfect crystallinity is fundamental to its electrochemical performance. Importantly, the preparation strategy for pure 3R-MoS 2 developed in this study does not rely on substrates, and the resulting products can be easily transferred and integrated. The proposed method is expected to contribute to the practical application of 3R-MoS 2 in energy storage and also provide a platform to explore stacking sequences and correlations between new phenomena and properties.
研究领域:
材料科学
·
纳米技术
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电化学
·
催化
·
理论化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Ruiqi Guo,Zhenglong Fan,Qiwei Zhou,Mengjie Ma,Wenxiang Zhu,Fan Liao,Hao Yang,Jiajie Wang,Zhenhui Kang,Minqi Sheng
Iridium oxide (IrO 2 ) has traditionally been considered to exhibit limited oxygen-reducing capacity. An effective approach to improve the oxygen reduction reaction (ORR) activity in parent catalytic materials is through atomic intercalation. However, the challenge lies in achieving a delicate balance between high ORR activity, structural stability, and minimizing the use of precious metals. Herein, we fabricate 3R-phase iridium oxide (3R-IrO 2 ) with superior ORR activity by intercalating a tiny amount of Pt (3.6 wt% Pt) into the interlayers of 3R-IrO 2 (3.6 wt% Pt-3R-IrO 2 ). When employed as an acidic ORR electrocatalyst, 3.6 wt% Pt-3R-IrO 2 shows a high half-wave potential (E 1/2 ) of 0.92 V (vs. RHE) in O 2 -saturated 0.1 M HClO 4 electrolyte, much better than those of Pt/C (0.850 V), 3R-IrO 2 (0.616 V), and Pt nanoparticles on 3R-IrO 2 surface (3.6 wt% Pt@3R-IrO 2 ) (0.618 V) electrocatalysts. It achieves high mass activity of 0.170 A mg Ir −1 at the potential of 0.9 V, which is 5.5 and 11.3 times than that of Pt/C (0.031 A mg Ir −1 ) and 3.6 wt% Pt@3R-IrO 2 (0.015 A mg Ir −1 ), respectively. Density functional theory (DFT) calculations and experiment results co-jointly demonstrate that the active center of Pt-3R-IrO 2 is anchored to the activated Ir atoms of the 3R-IrO 2 rather than Pt atoms. The d -band center of Ir 5 d orbitals of Pt-3R-IrO 2 is simultaneously regulated, which optimizes the energy barrier of adsorption/desorption toward the ORR process. Intriguingly, the intercalation of Pt atoms into trigonal rhodium oxide (Tri-RhO 2 ) also activates the ORR activity of Rh, suggesting the universality of this strategy. This discovery may provide a new and general way for activation of ORR activity of other precious metal-intercalated nonprecious metal oxide electrocatalysts.
研究领域:
材料科学
·
电化学
·
催化
·
能源材料
✓ 已验证
产品关联
DOI
高影响因子
BIOPROCESS AND BIOSYSTEMS ENGINEERING
·
2019
·Vol. 43
·期 1
·21-31
·
IF 2.371
Zhang Xiao-Jian,Wang Wen-Zhong,Zhou Rong,Liu Zhi-Qiang,Zheng Yu-Guo
Abstract tert -Butyl (3 R ,5 S ) - 6-chloro-3,5-dihydroxyhexanoate [(3 R ,5 S )-CDHH] is the key chiral intermediate to synthesize the side chain of the lipid-lowering drug rosuvastatin. Carbonyl reductases showed excellent activity for the biosynthesis of (3 R ,5 S )-CDHH. The requirement of cofactor NADH/NADPH leads to high cost for the industrial application of carbonyl reductases. In this study, a self-sufficient biocatalyst based on carbonyl reductase and NADP + co-immobilization strategy was developed on an amino resin carrier LX-1000HAA (SCR-NADP + @LX-1000HAA). The self-sufficient biocatalyst achieved in situ cofactor regeneration and showed the activity recovery of 77.93% and the specific activity of 70.45 U/g. Asymmetric synthesis of (3 R ,5 S )-CDHH using SCR-NADP + @LX-1000HAA showed high enantioselectivity (> 99% e.e.) and yield (98.54%). Batch reactions were performed for ten cycles without extra addition of NADP + , and the total yield of (3 R, 5 S )-CDHH achieved at 10.56 g/g biocatalyst. The present work demonstrated the potential of the self-sufficient biocatalyst for the asymmetric biosynthesis of rosuvastatin intermediate. Graphic abstract
研究领域:
生物化学
·
酶工程
·
药物合成
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
·
2020
·Vol. 21
·期 15
·5347
·
IF 4.556
Xiao-Ran Jing,Huan Liu,Yao Nie,Yan Xu
Fe(II)/2-ketoglutarate-dependent dioxygenase (Fe(II)/2-KG DO)-mediated hydroxylation is a critical type of C–H bond functionalization for synthesizing hydroxy amino acids used as pharmaceutical raw materials and precursors. However, DO activity requires 2-ketoglutarate (2-KG), lack of which reduces the efficiency of Fe(II)/2-KG DO-mediated hydroxylation. Here, we conducted multi-enzymatic syntheses of hydroxy amino acids. Using (2s,3r,4s)-4-hydroxyisoleucine (4-HIL) as a model product, we coupled regio- and stereo-selective hydroxylation ofl-Ile by the dioxygenase IDO with 2-KG generation from readily availablel-Glu byl-glutamate oxidase (LGOX) and catalase (CAT). In the one-pot system, H2O2significantly inhibited IDO activity and elevated Fe2+concentrations of severely repressed LGOX. A sequential cascade reaction was preferable to a single-step process as CAT in the former system hydrolyzed H2O2. We obtained 465 mM 4-HIL at 93% yield in the two-step system. Moreover, this process facilitated C–H hydroxylation of several hydrophobic aliphatic amino acids to produce hydroxy amino acids, and C–H sulfoxidation of sulfur-containingl-amino acids to yieldl-amino acid sulfoxides. Thus, we constructed an efficient cascade reaction to produce 4-HIL by providing prerequisite 2-KG from cheap and plentifull-Glu and developed a strategy for creating enzymatic systems catalyzing 2-KG-dependent reactions in sustainable bioprocesses that synthesize other functional compounds.Keywords:Fe(II)/2-ketoglutarate-dependent dioxygenase;2-ketoglutarate generation;regio- and stereo-selective synthesis;hydroxy amino acids;sequential cascade reaction
研究领域:
生物化学
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生物催化
·
合成生物学
·
酶学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Foodborne Pathogens and Disease
·
2023
·Vol. 20
·期 3
·90-99
·
IF 2.8
Wenyi Ran,Yuxi Yue,Feiwu Long,Kai Zhong,Jinrong Bai,Yue Xiao,Qian Bu,Yina Huang,Yanping Wu,Hong Gao
Staphylococcus aureus is a major foodborne pathogen that leads to various diseases due to its biofilm and virulence factors. This study aimed to investigate the inhibitory effect of 2R,3R-dihydromyricetin (DMY), a natural flavonoid compound, on the biofilm formation and virulence of S. aureus, and to explore the mode of action using transcriptomic and proteomic analyses. Microscopic observation revealed that DMY could remarkably inhibit the biofilm formation by S. aureus, leading to a collapse on the biofilm architecture and a decrease in viability of biofilm cell. Moreover, the hemolytic activity of S. aureus was reduced to 32.7% after treatment with subinhibitory concentration of DMY (p < 0.01). Bioinformation analysis based on RNA-sequencing and proteomic profiling revealed that DMY induced 262 differentially expressed genes and 669 differentially expressed proteins (p < 0.05). Many downregulated genes and proteins related to surface proteins were involved in biofilm formation, including clumping factor A (ClfA), iron-regulated surface determinants (IsdA, IsdB, and IsdC), fibrinogen-binding proteins (FnbA, FnbB), and serine protease. Meanwhile, DMY regulated a wide range of genes and proteins enriched in bacterial pathogenesis, cell envelope, amino acid metabolism, purine and pyrimidine metabolism, and pyruvate metabolism. These findings suggest that DMY targets S. aureus through multifarious mechanisms, and especially prompt that interference of surface proteins in cell envelope would lead to attenuation of biofilm and virulence.
研究领域:
微生物学
·
分子生物学
·
药理学
·
致病细菌
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED MATERIALS
·
2024
·Vol. 36
·期 32
·2400670
·
IF 27.4
Hanjun Jiang,Lei Li,Yao Wu,Ruihuan Duan,Kongyang Yi,Lishu Wu,Chao Zhu,Lei Luo,Manzhang Xu,Lu Zheng,Xuetao Gan,Wu Zhao,Xuewen Wang,Zheng Liu
Two-dimensional ultrathin ferroelectrics have attracted much interest due to their potential application in high-density integration of non-volatile memory devices. Recently, 2D van der Waals ferroelectric based on interlayer translation has been reported in twisted bilayer h -BN and transition metal dichalcogenides (TMDs). However, sliding ferroelectricity is not well studied in non-twisted homo-bilayer TMD grown directly by chemical vapor deposition (CVD). In this paper, for the first time, experimental observation of a room-temperature out-of-plane ferroelectric switch in semiconducting bilayer 3R MoS 2 synthesized by reverse-flow CVD is reported. Piezoelectric force microscopy (PFM) hysteretic loops and first principle calculations demonstrate that the ferroelectric nature and polarization switching processes are based on interlayer sliding. The vertical Au/3R MoS 2 /Pt device exhibits a switchable diode effect. Polarization modulated Schottky barrier height and polarization coupling of interfacial deep states trapping/detrapping may serve in coordination to determine switchable diode effect. The room-temperature ferroelectricity of CVD-grown MoS 2 will proceed with the potential wafer-scale integration of 2D TMDs in the logic circuit.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
FOOD CHEMISTRY
·
2023
·
IF 8.8
Haolin Zhang,Shiye Lin,Ruiwei Xie,Weizhi Zhong,Hui Wang,Mohamed A. Farag,Hidayat Hussain,Randolph R.J. Arroo,Xiaojia Chen,Jianbo Xiao
In the field of thermal degradation of flavonoids, current studies mainly focused on flavonols. However, the thermal degradation of dihydroflavonols in aqueous solution has received limited attention compared to flavonols. The single C2-C3 bonds of dihydroflavonols, which differs from the C2-C3 double bond in flavonols, may cause different degradation mechanisms. Dihydromyricetin (DMY) is a typical dihydroflavonol with six hydroxyl groups, and possesses various health effects. We explored the thermal degradation of DMY in neutral aqueous solution (pH 7) at 100 ℃. Ultra-performance liquid chromatography combined with photodiode array and electrospray ionization quadrupole-time-of-flight tandem mass spectrometric detection (UPLC-PDA-ESI-QTOF–MS/MS) provided suitable platform for exploring DMY degradation pathways, and negative ion mode was applied. Thermal treatment led to a decline in DMY level with time, accompanied by the appearance of various degradation products of DMY. Degradation mechanisms of DMY included isomerization, oxidation, hydroxylation, dimerization and ring cleavage. The pyrogallol-type ring B of DMY might be initially oxidized into ortho -quinone, which could further attack another DMY to form dimers. In addition, hydroxylation is likely to occur at C-2, C-3 of DMY or DMY dimers, which then further yields ring-cleavage products via breakage of the O1-C2 bond, C2-C3 bond, or C3-C4 bond. The 3-hydroxy-5-(3,3,5,7-tetrahydroxy-4-oxochroman-2-yl) cyclohexa-3,5-diene-1, 2-dione ( m / z 333.0244) and unknown compound m / z 435.0925 were annotated as key intermediates in DMY degradation. Four phenolic acids, including 3,4,5-trihydroxybenzoic acid ( m / z 169.0136, RT 1.4 min), 2,4,6-trihydroxyphenylglyoxylic acid ( m / z 197.0084, RT 1.7 min), 2-oxo-2-(2,4,6-trihydroxyphenyl) acetaldehyde ( m / z 181.0132, RT 2.4 min), and 2,4,6-trihydroxybenzoic acid ( m / z 169.0139, RT 2.5 min) were identified as the major end products of DMY degradation. In addition, 5-((3,5dihydroxyphenoxy) methyl)-3-hydroxycyclohexa-3,5-diene-1,2-dione (m / z 261.0399, RT 11.7 min) and unidentified compound with m / z 329.0507 (RT 1.0 min) were also suggested to be end products of DMY degradation. These results provide novel insights on DMY stability and degradation products. Moreover, the heat treatment of DMY aqueous solution was found to gradually reduce the antioxidant activities of DMY, and even destroy the beneficial effect of DMY on the gut microbiota composition.
研究领域:
药学化学
·
分析化学
·
食品科学
·
药理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 5
·2488-2495
·
IF 3.591
Bin Fang,Junjie Yao,Xiaojun Zhang,Liang Ma,Yaqi Ye,Jiayi Tang,Guifu Zou,Junchang Zhang,Lin Jiang,Yinghui Sun
Electrochemical nitrogen fixation provides an environmentally friendly strategy for producing ammonia (NH3) under ambient conditions. However, an inexpensive and efficient electrocatalyst for the electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is still needed. Herein, we report an efficient non-noble-metal electrocatalyst consisting of large scaled-up monocrystalline 3R MoS2, which is first utilized as an electrocatalyst for the NRR under ambient conditions. The NRR performance can be optimized via improving the electrochemically active surface area (ECSA) of MoS2. The NH3 yield rate and FE of MoS2-700 reach 8.8 μg h−1 mgcat−1 and 1.9%, respectively. Notably, 3R MoS2-700 shows excellent stability, with the negligible fluctuation of electrocatalytic activity after being recycled seven times. This study may provide a new strategy for structuring efficient electrocatalysts for the NRR.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）