APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2020
·Vol. 104
·期 23
·10005-10018
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IF 3.53
Guo Xiaolei,Wu Weibin,Zhang Mingliang,Wu Licheng,Huang Jianzhong
Abstract l -Tyrosine is a versatile compound used in the fine chemical, pharmaceutical, and functional food industries. Here, we report a bi-enzymatic cascade involving alanine racemase (ALR) and d -amino acid oxidase (DAAO) to produce pyruvate, as co-substrate for l -tyrosine production, from the cheap substrate l -alanine. The BpALR (ALR from Bacillus pseudofirmus ) was used as a whole-cell biocatalyst, converting l -alanine to d , l -alanine. The FsDAAO (DAAO from Fusarium solani ) was immobilized to oxidize the d -alanine generated in the first step to pyruvate. Both systems were combined as a continuous-flow reactor for maximized l -alanine-to-pyruvate conversion rates. The optimal parameters and appropriate conditions for FsDAAO immobilization were investigated. The pyruvate concentration of 86.6 g/L was achieved within 17 h. Subsequently, a whole-cell biocatalyst system for l -tyrosine production, catalyzed by the tyrosine phenol-lyase (TPL) from Erwinia herbicola (EhTPL), was developed, and a fed-batch approach was applied with phenol and the pyruvate produced with the ALR/DAAO system mentioned above. The concentration of phenol and pyruvate in the reactor should not exceed 7.5 g/L and 10 g/L, respectively. Significantly, the l -tyrosine concentration of 152.5 g/L was achieved within 10 h, demonstrating the great potential for high-efficiency production of l -tyrosine through the approach we established in this paper. Graphical abstract Key points • A specific bioreactor system for pyruvate produced from l -alanine was developed • The appropriate condition for immobilization of FsDAAO was investigated • A fed-batch process was established to produce l -tyrosine with recombinant E. coli • The bi-enzymatic cascade was successfully used for l -tyrosine production at low cost
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Jiaming Wang,Huixian Zhong,Kang An,Qiang Liu,Wu Jin,Yuan Liu
In this work, Ni–Co alloy nanoparticles (NPs) on La-doped SiO2 showed excellent selectivity toward ethanol for direct ethanol synthesis via CO hydrogenation. Over the catalyst with an optimal ratio of Ni/Co, the total alcohol selectivity reached 33.5%, of which ethanol occupied 47.0 wt %. The results demonstrated that the interaction between Co and Ni improved the ability to activate H2 and CO and adjusted the amount of the dissociatively and associatively adsorbed CO. Besides, the mutual dilution of nickel and cobalt in Ni–Co alloy NPs effectively reduced the isolated Co or Ni-clusters; thus, the formation of heavy hydrocarbons was suppressed. In the reaction process, Ni@Co–Co2C, a core–shell composite with a nickel core and Co–Co2C shell, was formed, which suppressed the loss of nickel species. Moreover, with the reaction going on, a small amount of poorly alloyed Co-clusters would be covered gradually by the formed coke, resulting in an increase in alcohol selectivity.
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Journal of Materials Chemistry C
·
2021
·Vol. 9
·期 6
·2178-2189
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IF 7.393
Menglei Dong,Mengyi Peng,Wei Wei,Huajie Xu,Chuntai Liu,Changyu Shen
Given the advantages of conductive hierarchical chiral nanocomposites for microwave absorption, a templated method was utilized to grow ZIF-67 in situ on helical CNTs (HCNTs). Due to the peculiar helical morphology and size of HCNTs, ZIF-67 exhibited distinctive growth features and pyrolysis features compared to those on planar substrates. In this work, the peculiar morphology was used to separate the nucleation and growth rate on the HCNT surface edges and grooves. Combining the control of solution concentration, reaction time and pyrolysis temperature of ZIF-67, hierarchical helical C/Co@CNT nanocomposites were successfully prepared at a 30 mM Co2+ concentration and a 700 °C pyrolysis temperature. Different from the traditional core–shell structure, this special nanomaterial possessed continuously helical doped carbon belt layers containing embedded Co particles deposited along the HCNT surface edge regions and exhibited a helically conductive path. These growth and pyrolysis mechanisms were explored in detail. With this special structure and composition, the abundant heterogeneous interface, rich defective polarization, good conduction loss, double cross polarization and good magnetic loss synergistically endowed it with an excellent microwave energy dissipation capacity. As a result, C/Co@CNT nanocomposites demonstrated excellent microwave absorption properties. When the thickness is 3.8 mm, the minimum reflection loss is −56.8 dB. The effective absorption bandwidth (RL ≤ −10 dB) is 4.8 GHz with a thickness of 1.6 mm and a filling rate of 25 wt%. We not only prepared an excellent electromagnetic wave absorber with a hierarchical helical structure, but also provided helpful guidelines for designing such a special nanostructure.
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ANALYTICAL SCIENCES
·
2021
·Vol. 37
·期 2
·293-299
·
IF 2.081
Liu ZHANG,Yue HOU,Xiaoyan GUO,Wei LIU,Congcong LV,Xing PENG,Zixuan ZHANG
In this work, a new chemiluminescence (CL) system of Co-Fe prussian blue analogs nanocubes (Co-Fe PBA NCs) that can catalyze luminol to produce strong CL in the absence of H2O2 was established. Co-Fe PBA NCs have the property of oxidase-like activity, and it can catalyze the generation of active oxygen radicals in a dissolved oxygen system. Since caffeic acid (CA) can remove reactive oxygen species in the system, a sensitive detection method for CA on a paper-based chip was developed. Under the optimal conditions, this method showed a good linear response to CA in the range of 10 – 800 ng mL−1 with a limit of 3 ng mL−1. The proposed method had been used for the determination of CA in tea samples. The results may open a new avenue for the catalytic property on luminol CL system without extra oxidants.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2020
·
IF 4.845
Kang Xiong,Yan Zhang,Qian Wen,Jia Luo,Yun Lu,ZhouXue Wu,BiQiong Wang,Yue Chen,Ling Zhao,ShaoZhi Fu
Multi-drug chemotherapy has been one of the most popular strategies for the treatment of malignant tumors, and has achieved desirable therapeutic outcomes. The objective of the present study is to develop biodegradable PCEC nanoparticles (NPs) for the co-delivery of paclitaxel (PTX) and curcumin (CUR), and investigate the antitumor effect of the drug delivery system (DDS: PTX-CUR-NPs) against breast cancer both in vitro and in vivo. The prepared PTX-CUR-NPs had a small size of 27.97 ± 1.87 nm with a low polydispersity index (PDI, 0.197 ± 0.040). The results exhibited slow release of PTX and CUR from the DDS without any burst effect. Further, the PTX-CUR-NPs displayed a dose-dependent cytotoxicity in MCF-7 cells with a higher apoptosis rate (64.29% ± 1.97%) as compared to that of free drugs (PTX + CUR, 34.21% ± 0.81%). The cellular uptake study revealed that the drug loaded PCEC polymeric nanoparticles were more readily uptaken by tumor cells in vitro. To evaluate the in vivo anti-tumor effect, the PTX-CUR-NPs were intravenously administered to BALB/c nude mouse xenografted with MCF-7 cells and the results exhibited significant inhibition of tumor growth with prolonged survival time and reduced side effect when compared with free drugs (PTX + CUR). Moreover, the administration of PTX-CUR-NPs treatment led to lower Ki67 expression (p < 0.05), and enhanced TUNEL positivity (higher apoptosis, p < 0.01) in tumor cells as compared to other treatment groups, suggesting the therapeutic efficacy of the DDS. Altogether, the present study suggests that the DDS PTX-CUR-NPs could be employed for the effective treatment of breast cancers in near future.
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TOXICOLOGY AND APPLIED PHARMACOLOGY
·
2020
·
IF 3.347
Cong Zhang,Lei Sheng,Ming Yuan,Junjie Hu,Yan Meng,Yong Wu,Liang Chen,Huifan Yu,Shan Li,Guohua Zheng,Zhenpeng Qiu
Orlistat (Xenical™), a US Food and Drug Administration (FDA)-approved anti-obesity drug, shows efficacy against multiple tumor types, including hepatocellular carcinoma (HCC), due to its ability to inhibit fatty acid synthase (FASN) activity. However, whether orlistat affects hepatocellular malignant transformation during hepatocarcinogenesis in vivo is unknown. This study assessed the antisteatotic and antitumorigenic efficacy of orlistat in a rapid HCC FVB/N mouse model established via hydrodynamic transfection of activated forms of AKT and c-Met proto-oncogenes. Human hepatoma cell lines were used for mechanical validation in vitro . Hematoxylin and eosin staining, immunohistochemistry, and immunoblotting were applied for the mechanistic investigation. The results revealed that when orlistat was administered in the early stage of AKT/c-Met-triggered hepatocarcinogenesis, it resulted in the elimination of hepatic tumor burden. Mechanistically, orlistat efficiently elevated PTEN expression and suppressed AKT/SREBP1/FASN signaling both in vivo and in vitro , impairing AKT/c-Met-driven de novo lipogenesis and aberrant proliferation. Altogether, this study demonstrates the antilipogenic and antiproliferative efficacy of orlistat in hepatocarcinogenesis, suggesting that orlistat may be beneficial for the treatment of HCC, especially in NAFLD-related HCCs featuring activated AKT/mTOR cascade and increased lipogenesis in livers.
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POLYMER TESTING
·
2020
·
IF 3.275
Meizhou Sun,Heling Guo,Jiliang Zheng,Yu Wang,Xinghuan Liu,Qian Li,Rongjie Wang,Xin Jia
Polymer coated fertilizer has been designed for gradual release of nutritional content of fertilizer to improve the utilization efficiency. However, the better slow release property of the coated fertilizer and simplified preparation process are still a huge challenge. The hydrophobic ODA-polyphenol film coated urea was prepared by one-step spraying for excellent nutrient release performance. Octadecylamine (ODA) was used to modify poly(tannic acid) (PTA) and poly(pyrogallol) (PPG) coating on substrates and prepare the hydrophobic ODA-PTA and ODA-PPG coated urea granules. The nutrient release rate of ODA-PTA and ODA-PPG coated fertilizers was much slower than PTA and PPG coated fertilizers in water and soil. The N release longevities of ODA-PTA coated fertilizers will be extended from 2 h to 30 days compared with PTA coated fertilizers. Moreover, pot experiments showed that coated fertilizer could effectively promote plant growth. This work will provide one-step spraying co-deposition approach to fabricate hydrophobic ODA-polyphenol film coated urea to improve the N release longevity, which can shine a light on the development of new slow release fertilizers (SRFs).
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Energy Technology
·
2020
·Vol. 8
·期 5
·2000008
·
IF 3.404
Chengrui Wang,Lei Zhang,Yuhai Dou,Luke Hencz,Lixue Jiang,Mohammad Al-Mamun,Porun Liu,Shanqing Zhang,Dan Wang,Huijun Zhao
Further commercial application of low-cost NiO-based anodes is hindered by their large volume expansion after full lithiation and relatively poor theoretical capacity. To improve these issues, transition metal (Fe, Co, or Mn)-modified triple-shelled NiO microspheres (TS-NiO) are successfully synthesized by using a hard template double-adsorption method. Among them, the Fe-modified TS-NiO (TS-NFO) exhibits an extraordinary lithium storage ability with high reversible capacity and outstanding cycling stability (2061.1 mAh g −1 after 800 cycles at 0.5 A g −1 ), which is the highest performing nickel oxide-based anode reported to date. The outstanding electrochemical performance of TS-NFO can be ascribed to its unique triple-shelled structure. The inner core of TS-NFO is composed of NiO and is encapsulated by two outer shells which are composed of a mixture of α-Fe 2 O 3 and NiFe 2 O 4 , resulting in a unique hollow triple-shelled structure (NiO@α-Fe 2 O 3 /NiFe 2 O 4 ). The void space between the triple shells leaves room for their volume changes during lithiation/delithiation, which improves the cycling stability. In addition, the introduced α-Fe 2 O 3 /NiFe 2 O 4 outer shells increase the energy density and reversible capacity due to a synergistically interactive effect.
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APPLIED SURFACE SCIENCE
·
2020
·
IF 6.182
Fangxu Dai,Ying Wang,Xinran Zhou,Ruiyang Zhao,Jishu Han,Lei Wang
An efficient visible light responsive ZnIn 2 S 4 @NH 2 -MIL-53(Fe/Co 0.75 ) nanocomposite was prepared for photocatalytic hydrogen production application. Under visible light irradiation, the ZnIn 2 S 4 @NH 2 -MIL-53(Fe/Co 0.75 ) photocatalyst displayed improved photocatalytic performance and the hydrogen production rate reached to 161724.8 μmol/g in 6 h. The nanocomposite with large specific surface area and mesoporous structure increased the light absorption, improved the electrons transfer and suppressed the recombination of photogenerated electron-hole pairs, thus exhibiting efficient photocatalytic hydrogen production performance. The controllable synthesis of ZnIn 2 S 4 @NH 2 -MIL-53(Fe/Co 0.75 ) nanocomposite as a high-efficiency photocatalyst would have broad prospect for water splitting hydrogen production application.
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CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Hao Zhao,Yuebin Zhao,Jiabao Xu,Xin Feng,Guanyu Liu,Yanbing Zhao,Xiangliang Yang
Combination chemotherapy, such as doxorubicin (Dox) plus cisplatin, based on co-assembling nanoparticles plays increasingly important role in the clinical treatment of cancer. But their synergistic antitumor effect is highly limited by unmatched release behavior of Dox and cisplatin. To enhance the synergistic antitumor effect of Dox and cisplatin, herein, an acidic triblock polymer ( p AA 100 - b - p NIPAM 200 - b - p AA 100 , PNA) was developed as a temperature sensitive template for programmable fabrication of two antitumor drugs (Dox and cisplatin). In these co-assembly nanogels, [email protected] nanogels show compact 3D network cisplatin-shell surrounding Dox-loading core, enabling parallel release of Dox and cisplatin, which is beneficial to maximizing the synergistic effect of Dox and cisplatin. Moreover, [email protected] nanogels could be efficiently internalized into tumor cells mainly by caveolin-mediated pathway. In in vivo evaluation on 4T1-bearing BALB/c mice, after single injection, [email protected] nanogels exhibited much stronger suppression of tumor growth, proliferation and metastasis, and induction of apoptosis and necrosis of tumor tissue/cells than [email protected] + [email protected] and [email protected] groups thanks to the parallel release of Dox and cisplatin. In addition, [email protected] nanogels showed a distinct transition from free-flowing sol to free-standing gel at critical gellating temperature (CGT), facilitating the long-term tumor retention and the optimally synergistic antitumor effect of Dox and cisplatin. The programmable fabrication with PNA was promising to be developed as an efficient approach for improving the antitumor efficacy of combination chemotherapy.
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NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 25
·10739-10746
·
IF 3.288
Xuecheng Liu,Linjie Yan,Linxin He,Zurun Yao,Linfeng You,Lin Liu,Guilin Zhou,Hongyu Huang
The Co–C3N4/BiPO4 photocatalyst is facilely synthesized for application in photocatalytic water splitting. The physical and chemical properties of Co–C3N4/BiPO4 are studied by a wide range of characterization methods. The Co–CN/BP photocatalyst shows good photocatalytic activity for H2 evolution by water splitting without using a noble metal. The Co–C3N4/BiPO4 composite with 5 wt% Co–C3N4 loading exhibits a superior photocatalytic H2 evolution rate of 23.9 μmol h−1 g−1. The remarkable enhancement of the photocatalytic H2 evolution activity of Co–C3N4/BiPO4 composites is mainly ascribed to the effective charge transfer and separation of the electron–hole pairs by the lattice-matched heterojunction structure. This work extends opportunities for the design of non-noble metal photocatalysts with efficient photocatalytic water splitting.
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Nanoscale
·
2020
·Vol. 12
·期 27
·14882-14894
·
IF 6.895
Junfang Ding,Liping Li,Ye Wang,Huixia Li,Min Yang,Guangshe Li
Highly dispersed nanoalloys with a tailored metal–oxide interface are pivotal in developing advanced catalysts with superior performance for applications. Herein, a series of highly dispersed Pt/NiFeAl nanoalloys on amorphous supports were successfully fabricated by a topological transformation of layered-double-hydroxide nanosheets. With increasing reduction temperature, samples Pt/NiFeAl-x (x = reduction temperature) showed a progressive transformation from Pt/NiFeAl-LDH to a mixture (Pt, NiFe alloys, FeOy, and NiOy) supported on amorphous Al2O3, which eventually transformed to atomically dispersed PtNiFe alloys supported on amorphous Al2O3. Systematic sample characterization demonstrates that amorphous alumina-supported PtNiFe nanoalloys are merited by excellent redox ability, outstanding O2 activation ability, and moderate CO adsorption strength. When tested as catalysts for CO oxidation, all samples have demonstrated an apparent interfacial effect on catalytic performance, among which Pt/NiFeAl-600 shows a strikingly high CO oxidation activity at low-temperatures coupled with a broader operation temperature window (i.e. CO conversion >99.0%, 100–400 °C). Such a topological transformation strategy has proven applicable for generating atomically dispersed nanoalloys on amorphous supports for catalytic applications.
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