METABOLIC ENGINEERING
·
2017
·
IF 8.142
Lu Dai,Fei Tao,Hongzhi Tang,Yali Guo,Yaling Shen,Ping Xu
Primordial enzymes are proposed to possess broad specificities. Through divergence and evolution, enzymes have been refined to exhibit specificity towards one reaction or substrate, and are thus commonly assumed as “specialists”. However, some enzymes are “generalists” that catalyze a range of substrates and reactions. This property has been defined as enzyme promiscuity and is of great importance for the evolution of new functions. The promiscuities of two enzymes, namely glycerol dehydratase and diol dehydratase, were herein exploited for catalyzing long-chain polyols , including 1,2-butanediol, 1,2,4-butanetriol, erythritol , 1,2-pentanediol, 1,2,5-pentanetriol, and 1,2,6-hexanetriol. The specific activities required for catalyzing these six long-chain polyols were studied via in vitro enzyme assays , and the catalytic efficiencies were increased through protein engineering. The promiscuous functions were subsequently applied in vivo to establish 1,4-butanediol pathways from lignocellulose derived compounds, including xylose and erythritol. In addition, a pathway for 1-pentanol production from 1,2-pentanediol was also constructed. The results suggest that exploiting enzyme promiscuity is promising for exploring new catalysts, which would expand the repertoire of genetic elements available to synthetic biology and may provide a starting point for designing and engineering novel pathways for valuable chemicals.
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POLYMER TESTING
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2021
·
IF 4.282
Jing Zhang,Pai Peng,Lingdong Chen,Liping Zhao,Jie Feng
In recent years, hydrogels with antifouling properties and good biocompatibility have attracted great attention in bio-devices, but most of them are lack of eminent mechanical properties that limit their practical application greatly. In this work, a newly hybrid ion-covalent cross-linked double network (DN) hydrogels with excellent antifouling as well as mechanical properties were prepared by a simple one-pot method based on sodium alginate and a kind of antifouling material, N -hydroxyethyl acrylamide (HEAA). The DN hydrogel have excellent mechanical properties, including high tensile strength (1.32 MPa), high elastic modulus (0.31 MPa) and preeminent fatigue resistance. Besides, the DN hydrogel have good antifouling properties suggested by protein adsorption and cell adhesion experiments. In addition, they also exhibit highly in vitro compatibility. These properties make the DN hydrogels suitable for application in different fields, such as tissue scaffolds, implantable devices and so on.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Youyou Feng,Jing Qin,Yu Zhou,Qin Yue,Jing Wei
Nanozyme has been regarded as an efficient antibiotic to kill bacteria using the reactive oxygen species (ROS) generated by Fenton-like reaction. However, its activity is still unsatisfied and requires large amount of hydrogen peroxide with side effects toward normal tissues. Herein, spherical mesoporous Fe-N-C single-atom nanozyme (SAzyme) is designed for antibacterial therapy via photothermal treatment enhanced Fenton-like catalysis process. Due to the large pore size (4.0 nm), high specific surface area (413.9 m 2 g −1 ) and uniform diameter (100 nm), the catalytic performance of Fe-N-C SAzyme is greatly improved. The Michaelis-Menten constant ( K m ) is 4.84 mmol L −1 , which is similar with that of horseradish peroxidase (3.7 mmol L −1 ). Moreover, mesoporous Fe-N-C SAzyme shows high photothermal conversion efficiency (23.3 %) owing to the carbon framework. The catalytic activity can be enhanced under light irradiation due to the elevated reaction temperature. The bacteria can also be killed via physical heat effect. Due to the synergistic effect of nanozyme catalysis and photothermal treatment, the antibacterial performance is much higher than that using single antibacterial method. This work provides an alternative for combined antibacterial treatment via photothermal treatment assisted catalytic process using spherical mesoporous single-atom nanozyme as an antibiotic.
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ANALYTICA CHIMICA ACTA
·
2021
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IF 6.558
Liping Sun,Chao Li,Yong Yan,Yue Yu,Hao Zhao,Zijue Zhou,Feng Wang,Yi Feng
Single atom nanozymes (SAzymes) represent the state-of-the-art technology in nanomaterial-based catalysis, which have attracted attentions in catalysis, cancer treatment, disinfection and biosensing fields. However, numerous SAzymes suffered from low aqueous dispersion and without recognition capacity, which impeded their applications in bioanalysis . Herein, we engineered DNA onto SAzymes to obtain the DNA/SAzymes conjugates , which significantly improved the aqueous dispersion and recognition ability of SAzymes. We synthesized iron SAzymes (Fe–N–C SAzymes) as the catalytic nanomaterials, and investigated the interactions between Fe–N–C SAzymes and DNA. We compared A 15 , T 15 and C 15 adsorption of Fe–N–C SAzymes in HEPES containing 2 mM MgCl 2 . We found that 50 μg mL −1 Fe–N–C SAzymes produced nearly 100% A 15 adsorption, 90% T 15 adsorption and only 69% C 15 adsorption, indicating that adenine and thymine had higher adsorption affinity on Fe–N–C SAzymes. More importantly, DNA modification did not affect the peroxidase-like activity of Fe–N–C SAzymes and the bioactivity of the adsorbed DNA. Taking the advantage of the diblock DNA with one DNA sequence (adenine) binding to Fe–N–C SAzymes and the other DNA sequence (i.e., aptamer) binding to cancer cells, we designed Apt/Fe–N–C SAzymes for colorimetric detection of cancer cells, which offered new insights for the use of SAzymes in biomedicine .
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Journal of Materials Chemistry B
·
2021
·Vol. 10
·期 5
·717-727
·
IF 6.331
Zhiyu Li,Yichun Gao,Huinan Zhang,Fang Lan,Yao Wu
Alterations in plasma membrane glycoproteins (PMGs) have been identified as a hallmark of cancer. The comparison and identification of differential PMGs is significant for finding new markers and understanding pathological processes. However, the research on PMGs is often constrained by the low abundance and the disturbance of abundant endogenous biomolecules during direct analysis. Here, we report a bottom-up strategy to enrich the PMGs of breast cancer cells using hydrophilic magnetic covalent triazine frameworks (CTFs). A total of 972 N-glycopeptides and 1006 N-glycosites belonging to 526 N-glycoproteins were enriched in MCF-10A plasma membrane tryptic digest by magnetic CTFs. And 680 N-glycopeptides and 806 N-glycosites belonging to 443 N-glycoproteins were enriched in SK-BR-3 plasma membrane tryptic digest. Furthermore, comparative analysis was performed based on gene ontology to verify breast cancer biomarkers (SUSD2 and ALCAM) and differential PMGs’ function. This strategy which systematically integrates efficient enrichment of differential PMGs and in-depth comparative analysis has great potential for helping illuminate the atlas of breast cancer PMGs and the causes of tumor metastasis.
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GREEN CHEMISTRY
·
2018
·Vol. 20
·期 10
·2320-2327
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IF 8.586
Alei Zhang,Guoguang Wei,Xiaofang Mo,Ning Zhou,Kequan Chen,Pingkai Ouyang
In this study, we propose a novel biological fermentation method to process chitin powder utilizing the bacteria Chitinolyticbacter meiyuanensis SYBC-H1. The chitin obtained from this process is called CBF, and it was further investigated for N-acetyl-D-glucosamine (GlcNAc) enzymatic production. This fermentative treatment caused chitin powder to acquire a visible fleecy structure, and scanning electron microscopy showed that the surface of the CBF was a fiber-like structure with a diameter ranging from 10 nm to 200 nm. Moreover, Fourier transform infrared spectrometry, X-ray diffraction and gel permeation chromatography revealed that the crystallinity and average molecular weight of the chitin clearly decreased in the absence of deacetylation following bacterial fermentation treatment. The optimal conditions for bacterial treatment of chitin were determined at 25 °C, 200 rpm, and an initial pH of 7.5 for 12 h. Additionally, 19.2 g L−1 of GlcNAc could be obtained with a yield of 96% from 20 g L−1 of CBF in a batch enzymatic reaction within 6 h. This new approach provided an environmentally friendly and mild method for reducing the crystallinity of chitin and enhancing GlcNAc conversion without the use of oxidants, acids, or other environment unfriendly reagents.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Md Manik Mian,Guijian Liu,Biao Fu,Yu Song
Sewage sludge (SS), the inevitable byproduct of wastewater treatment plants, is facing numerous challenges of environmentally safe and cost-effective disposal. Thus, exploration of efficient SS valorization technique is highly desired. In this study, a sludge derived carbon-supported MnO x as a catalyst (ASMn-Nb) was synthesized through NH 4 OH activation and pyrolysis (800 °C) to enhance peroxymonosulfate (PMS) decomposition and subsequent degradation of acid orange 7 and rhodamine B. The sample characterization indicated that MnCl 2 conditioning produces mixed valent Mn oxides on ASMn-Nb, while NH 4 OH activation significantly enhances N-heteroatoms, surface area, and microporosity. The as-synthesized hybrid catalyst exhibited excellent PMS decomposition ability in a wide range of pH, which enhances AO7 removal efficiency 16%–100% in 40 min compared with that treated with raw sludge biochar. Moreover, the catalyst is recyclable, chemically stable, and produce negligible metal leaching during catalysis. Further investigation of catalytic mechanisms revealed that both radicle and non-radicle processes governing PMS decomposition, whereas mediated electron transfer as the primary and 1 O 2 , SO 4 − , and OH radicals induced catalysis as the secondary mechanisms of PMS activation and subsequent AO7 degradation. Finally, a probable mechanism of PMS decomposition over ASMn-Nb and AO7 degradation path is proposed. This study concurrently provides a facile route of improving the catalytic performance of sludge derived-biochar and a probable SS valorization technique.
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APPLIED SURFACE SCIENCE
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2022
·
IF 7.392
Ziyan Du,Jingxi Qin,Kang Zhang,Linwei Jia,Ke Tian,Junfeng Zhang,Haijiao Xie
Single atom catalysts with high-catalytic activity have been applied in many fields. In this work, single Fe atoms (FeSA) showed excellent catalytic performance on P-nitrophenol (PNP) degradation with high total organic carbon (TOC) removal rate and high turnover frequency (TOF). The high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) results show that Fe species in FeSA are mainly single Fe atom. X-ray absorption near-edge structure (XANES) and density functional theory (DFT) calculations show that each single Fe atom is anchored by four N atoms in the form of FeN 4 active site. This coordination environment enables FeSA possesses unique geometric configuration and highly uniform active sites, which is conducive to organic pollutant adsorption and peroxymonosulfate (PMS) activation. In addition, FeSA could maintained excellent catalytic activity in complex water bodies containing different anions and humic acids. The active species in the FeSA/PMS system were also investigated. It is found that the main oxidative active species in the system are O 2 •− and 1 O 2 . This work shows that FeSA was a highly efficient single atom catalyst for the degradation of organic pollutants and has a wide application prospect in advanced oxidation processes.
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Molecular Catalysis
·
2022
·
IF 5.089
Xiao-Chao Chen,Lin Guo,Guang-Hui Shi,Kai-Chun Zhao,Yong Lu,Ye Liu
Carbon dioxide (CO 2 ) was found to serve as a novel and green catalyst for the first time in N -formylation of amines with N, N -dimethylformamide (DMF), wherein only the aliphatic amines were applicable to afford the formamides in the yield of 71∼95%. The isotope labeling experiment with DMF- d 7 indicated that the N -formyl group in the formylated product was originated from DMF rather than CO 2 . The control experiments and the in situ high-pressure FT-IR spectra demonstrated that the formation of the carbamate salt of cyclohexylammonium cyclohexylcarbamate ( A ) derived from the reaction of CO 2 with cyclohexylamine was the driving force for this reaction. Accordingly, the mechanism of CO 2 -catalyed N -formylation of aliphatic amines with DMF was proposed, involving the formation of carbamate salt intermediate with enhanced nucleophilicity in anion in favor of the attack on carbonyl-group of DMF.
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JOURNAL OF MEMBRANE SCIENCE
·
2018
·
IF 6.578
Nanjun Chen,Chuanrui Lu,Yunxi Li,Chuan Long,Hong Zhu
Herein, for realizing the high efficiency and long lifetime of hydroxide exchange membranes (HEMs) for alkaline membrane fuel cell (AMFC) applications, a series of robust poly(biphenyl piperidinium) (PBP)/6-azaspiro[5.5] undecane (ASU)-functionalized polyphenyl ether (ASU-PPO) membranes were prepared by a crosslinked strategy. Crosslinked PBP-ASU-PPO membrane combines the advantage of PBP and ASU-PPO membranes as well as addresses the problem of high water uptake of PBP and the insufficient film-forming property of ASU-PPO. As expected, these crosslinked PBP-ASU-PPO membranes exhibit commendably comprehensive performances, such as good ion conductivity, durability, and mechanical properties . The crosslinked PBP-ASU-PPO membrane reaches a maximum OH − conductivity of 128 mS/cm at 80 °C, accompanying with a 15.7% membrane swelling. Besides, only 13.6% degradation in Cl − conductivity was observed in PBP-ASU-PPO after alkaline treatment in 1 M NaOH at 80 °C for 2000 h. Besides, the selected PBP-ASU-PPO membrane achieves a maximum power density of 324 mW/cm 2 at current density of 750 mA/cm 2 .
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CARBOHYDRATE POLYMERS
·
2021
·
IF 9.381
Tao Liu,Shaohua Gou,Yang He,Shenwen Fang,Lihua Zhou,Guangjun Gou,Lang Liu
In this paper, N -methylene phosphonic acid chitosan (NPCS-PEI) was synthesized from chitosan, phosphorous acid , formaldehyde and hyperbranched polyethyleneimine (PEI), and Cu 2+ and Pb 2+ removal performance was examined in aqueous solution. NPCS-PEI exhibited three-dimensional porous architectures, with a specific surface area of 490.61 m 2 /g. The effects of pH, initial concentration, adsorption time, temperature and ionic strength on the adsorption capacity were investigated. The adsorption kinetics indicated that Cu 2+ and Pb 2+ adsorption onto NPCS-PEI follows a pseudo-second-order model. The adsorption isotherms agree well with the Langmuir isotherm model, and the maximum adsorption capacities of Cu 2+ and Pb 2+ on the NPCS-PEI are approximately 276.12 and 645.16 mg/g, respectively. The adsorption efficiency of NPCS-PEI remained above 85% after 5 adsorption-desorption successive cycles. Moreover, the NPCS-PEI aerogels had selective adsorption toward Cu 2+ . The FTIR and XPS analysis proved that amino, hydroxyl, and phosphonic acid groups were involved in the chelation with metal ions .
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Molecular Catalysis
·
2021
·
IF 5.062
Guoqin Wang,Gangli Zhu,Yong Ding,Chungu Xia,Zhen Li
Polyoxymethylene dialkyl ethers, which can be blended into diesel fuels, have attracted increasing attentions due to their advantages for fuel additives. It can utilize bioethanol and biomass syngas, helping to achieve the carbon neutral target earlier. Polyoxymethylene diethyl ethers (PODEE n ) synthesis requires efficient catalysts with high performance. In this work, the mesoporous acidic functional N-containing ZrN x O y catalysts were prepared with a Sol-Gel assisted solvothermal method. The acid nature and strength, morphology, crystalline structure and pore distribution of catalysts were characterized by fourier transform infrared (FT-IR) spectroscopy, pyridine-adsorption infrared spectra (Py-IR), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), N 2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy (XPS), temperature-programmed desorption of ammonia (NH 3 -TPD) etc, showing catalyst possessing crystalline-amorphous mixed domains with smaller defective tetragonal nanoparticles and mesopores . The catalysts were applied in PODEE n synthesis, showing excellent activity and selectivity under mild conditions. And the high trioxane (TOX) conversion of 93 % and excellent PODEE 2−8 selectivity of 98 % can be achieved at 80 °C under atmospheric pressure owning to the superior properties.
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