APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Quanfeng Xing,Min Zhang,Xiuquan Xu,Bo Zhang,Yun Duan,Yi Wei,Jiahui Wang,Mingyang Li
Previous studies have proved that the promoted interactions with bacteria was closely responsible for the improved inactivation efficiency of photocatalysts. Herein, for the first time, the cationic polymer polyethyleneimine (PEI) grafted O-doped g-C 3 N 4 (denoted as PEI/OCN) was successfully fabricated by combination one-pot thermal-polymerization and subsequent covalent cross-linking reaction. Benefiting from the synergistic effect of O-doping and PEI-grafting, the obtained PEI/OCN possessed an extended and intensive visible light response, accelerated photogenerated charge transport, good hydrophilicity as well as enough electrostatic adhesion to bacteria. As a result, PEI/OCN exhibited a dramatically boosted reactive oxygen species (ROS) generation and outstanding rapid photocatalytic bactericidal capability, achieving 7.0 log CFU mL −1 inactivation efficiency of Escherichia coli ( E. coli ) within 30 min visible light exposure. Radical trapping and electron spin resonance (ESR) experiments revealed that superoxide radicals ( • O 2 − ) were crucially dominated the superior photocatalytic disinfection activity. Overall, the presented work provided a rationally designing of novel metal-free g-C 3 N 4 -based photocatalysts for efficient elimination of bacterial contaminations.
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AMB Express
·
2021
·Vol. 11
·期 1
·1-13
·
IF 3.298
Zhuang Wenjin,Liu Hanyu,Zhang Ying,He Junyao,Wang Pu
( R )-1-[3-(Trifluoromethyl)phenyl]ethanol (( R )-MTF-PEL) is an important chiral building block for the synthesis of a neuroprotective compound, ( R )-3-(1-(3-(trifluoromethyl)phenyl)ethoxy)azetidine-1-carboxamide. In this work, an effective whole-cell-catalyzed biotransformation was developed to produce ( R )-MTF-PEL, and its productivity was increased by medium engineering strategy. The recombinant E. coli BL21(DE3)-pET28a(+) - LXCAR-S154Y variant affording carbonyl reductase was adopted for the reduction of 3'-(trifluoromethyl)acetophenone to ( R )-MTF-PEL with enantiomeric excess (ee) > 99.9%. The addition of 0.6% Tween-20 (w/v) boosted the bioreduction, because the substrate concentration was increased by 4.0-fold than that in the neat buffer solution. The biocatalytic efficiency was further enhanced by introducing choline chloride: lysine (ChCl:Lys, molar ratio of 1:1) in the reaction medium, because the product yield reached 91.5% under 200 mM substrate concentration in the established Tween-20/ChCl:Lys-containing system, which is the highest ever reported for ( R )-MTF-PEL production. The optimal reduction conditions were as follows: 4% (w/v) ChCl:Lys, 12.6 g (DCW)/L recombinant E. coli cells, pH 7.0, 30 ℃ and 200 rpm, reaction for 18 h. The combined strategy of surfactant and NADES has great potential in the biocatalytic process and the synthesis of chiral alcohols.
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高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2014
·Vol. 173
·期 8
·2042-2053
·
IF 1.687
He Yu-Cai,Yang Zhen-Xing,Zhang Dan-Ping,Tao Zhi-Cheng,Chen Chao,Chen Yi-Tong,Guo Fei,Xu Jian-He,Huang Lei,Chen Rui-Jie,Ma Xiao-Feng
The reductase (PgCR) from recombinant Escherichia coli CCZU-Y10 displayed high reductase activity and excellent stereoselectivity for the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl ( S )-4-chloro-3-hydroxybutanoate (( S )-CHBE). To efficiently synthesize ( S )-CHBE (>99 % enantiomeric excess (ee)), the highly stereoselective bioreduction of COBE into ( S )-CHBE with the whole cells of E. coli CCZU-Y10 was successfully demonstrated in a dibutyl phthalate-water biphasic system. The appropriate ratio of the organic phase to water phase was 1:1 ( v / v ). The optimum reaction temperature, reaction pH, cosubstrate, NAD + , and cell dosage of the biotransformation of 100 mM COBE in this biphasic system were 30 °C, 7.0, mannitol (2.5 mmol/mmol COBE), 0.1 μmol/(mmol COBE), and 0.1 g (wet weight)/mL, respectively. Moreover, COBE at a high concentration of (1,000 mM) could be asymmetrically reduced to ( S )-CHBE in a high yield (99.0 %) and high enantiometric excess value (>99 % ee). Significantly, E. coli CCZU-Y10 shows high potential in the industrial production of ( S )-CHBE (>99 % ee).
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高影响因子
FOOD CHEMISTRY
·
2024
·
IF 8.5
Dan Zhao,Yan Jiao,Changpeng Zhang,Xincai Xiao
The sensitive detection of foodborne pathogenic and rapid antibiotic susceptibility testing (AST) is of great significance. This paper reports the enzyme-triggered in situ synthesis of yellow emitting silicon nanoparticles (SiNPs) and the detection of Escherichia coli ( E. coli ) O157:H7 in food samples and the rapid AST. The rapid counting of E. coli O157:H7 has been achieved through direct visual observation, equipment detection, and smartphone digitalization. A simple detection platform based on smartphone senses and cotton swabs has been established. Meanwhile, rapid AST based on enzyme-catalyzed SiNPs can intuitively obtain colorimetric samples. This paper established a system for bacterial enzyme-triggered in situ synthesis of SiNPs, with high responsiveness, luminescence ratio, and specificity. The detection limit for E. coli O157:H7 can reach 100 CFU/mL during 5 h, and the recovery efficiency ranges from 90.14% to 110.16%, which makes it a promising strategy for the rapid detection of E. coli O157:H7 and AST.
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Materials Research Express
·
2022
·Vol. 9
·期 9
·095001
·
IF 2.025
Wanshu Yan,Pingping Hu,Yiguo Jiang,Xiuquan Xu,Xianfeng Ma,Mengru Wang,Xinyue Bao
Photocatalytic inactivation has been proved to be an effective strategy to eliminate pathogenic bacteria in water. Herein, a novel 0D/2D p-n heterojunction of Ag2S-anchored P-doped g-C3N4 (Ag2S/PCN) were constructed by a simple two-step process coupling one-pot calcination and ultrasonic-assisted synthesis. The photocatalytic performance of as-prepared Ag2S/PCN composites was investigated by inactivating multidrug-resistant E. coli under visible light irradiation. The results indicated that Ag2S/PCN-5 possessed outstanding photocatalytic inactivation activity and superior stability, which could completely inactivate 7.0 log E. coli cells within 60 min. The enhanced photocatalytic activity of Ag2S/PCN-5 was mainly attributed to the elevated visible-light response and improved production and transfer of photoexcited charges. In addition, the free radicals trapping experiments results revealed that h+ and •O2− were predominantly responsible for the efficient inactivation activity. Finally, according to the 0D/2D structure and energy band configuration analysis, the enhanced p-n type heterojunction photocatalytic inactivation mechanism of Ag2S/PCN was discussed in detail.
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DIAGNOSTIC MICROBIOLOGY AND INFECTIOUS DISEASE
·
2025
·
IF 1.8
Taobo Liang,Junyu Cao,Liyan Zhuo,Chunhong Zhu,Yufei Wang,Shanshan Hu,Jiaxing Hao,Guangsheng Zhuo,Tao Wang
Microbial contamination during the collection of placental and umbilical cord tissues presents a significant challenge to the safety of stem cell-based therapies and the commercial storage. In this study, microbial contamination analysis of a large cohort placental and umbilical cord samples collected recent revealed with 38 distinct microbial species identified. Contaminated samples were predominantly from vaginal deliveries (82.7%), and higher contamination rates were observed in mothers aged ≥30 years. For rapid monitoring, we developed a novel multiplex quantitative PCR assay for simultaneous detection of the most prevalent contaminants: Escherichia coli, Candida albicans , and Enterococcus faecalis . The assay demonstrated robust detection limits in pure cultures, with a lower limit of detection of 10 2 CFU/mL for E. coli and C. albicans , and 10 1 CFU/mL for E. faecalis . Based on the analytical performance described above, this multiplex qPCR assay establishes a robust framework for rapid, quantitative surveillance of microbial contaminants in placental-derived biologics. By enabling same-shift screening with sensitivity down to 10 CFU/mL, the method significantly enhances quality assurance protocols for stem cell banking a critical advancement toward safer clinical translation of placental-based therapeutics.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·1831-1837
·
IF 4.831
Yang Zhen,Liu Yan,Lei Chong,Sun Xue-cheng,Zhou Yong
We report on a method for ultrasensitive detection and quantification of the pathogen Escherichia coli ( E. coli ), type O157:H7. It is using a tortuous-shaped giant magnetoimpedance (GMI) sensor in combination with an open-surface microfluidic system coated with a gold film for performing the sandwich immunobinding on its surface. Streptavidin-coated super magnetic Dynabeads were loaded with biotinylated polyclonal antibody to capture E. coli O157:H7. The E. coli -loaded Dynabeads are then injected into the microfluidics system where it comes into contact with the surface of gold nanofilm carrying the monoclonal antibody to form the immunocomplex. As a result, the GMI ratio is strongly reduced at high frequencies if E. coli O157:H7 is present. The sensor has a linear response in the 50 to 500 cfu·mL −1 concentration range, and the detection limit is 50 cfu·mL −1 at a working frequency of 2.2 MHz. In our perception, this method provides a valuable tool for developing GMI-based microfluidic sensors systems for ultrasensitive and quantitative analysis of pathogenic bacteria. The method may also be extended to other sensing applications by employing respective immunoreagents.
Fig. (a) Graphical illustration of the test setup. (b) Relationship of GMI signal vs. E. coli O157:H7 concentration.
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BIORESOURCE TECHNOLOGY
·
2014
·
IF 5.039
Yu-Cai He,Dan-Ping Zhang,Zhi-Cheng Tao,Xian Zhang,Zhen-Xing Yang
An NADH-dependent reductase (SsCR) was discovered by genome data mining. After SsCR was overexpressed in E. coli BL21, recombinant E. coli CCZU-A13 with high reductase activity and excellent stereoselectivity for the reduction of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl ( R )-4-chloro-3-hydroxybutanoate (( R )-CHBE) was screened using one high-throughput colorimetric screening strategy. After the reaction optimization, a highly stereoselective bioreduction of COBE into ( R )-CHBE (>99% ee ) with the resting cells of E. coli CCZU-A13 was successfully demonstrated in n -butyl acetate–water (10:90, v/v) biphasic system. Biotransformation of 600 mM COBE for 8 h in the biphasic system, ( R )-CHBE (>99% ee ) could be obtained in the high yield of 100%. Moreover, the broad substrate specificity in the reduction of aliphatic and aromatic carbonyl compounds was also found. Significantly, E. coli CCZU-A13 shows high potential in the industrial production of ( R )-CHBE (>99% ee ) and its derivatives.
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BIORESOURCE TECHNOLOGY
·
2016
·
IF 4.917
Yu-Cai He,Zhi-Cheng Tao,Jun-Hua Di,Liang Chen,Lin-Bing Zhang,Dan-Ping Zhang,Gang-Gang Chong,Feng Liu,Yun Ding,Chun-Xia Jiang,Cui-Luan Ma
It was the first report that the concentrated hydrolyzates from the enzymatic hydrolysis of dilute NaOH (3 wt%)-soaking rice straw at 30 °C was used to form [Bmim]PF 6 -hydrolyzate (50:50, v/v) media for bioconverting ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl ( R )-4-chloro-3-hydroxybutanoate [( R )-CHBE] (>99% e.e. ) with recombinant E. coli CCZU-A13. Compared with pure glucose, the hydrolyzates could promote both initial reaction rate and the intracellular NADH content. Furthermore, emulsifier OP-10 (20 mM) was employed to improve the reductase activity. Moreover, Hp-β-cyclodextrin (0.01 mol Hp-β-cyclodextrin/mol COBE) was also added into this bioreaction system for enhancing the biosynthesis of ( R )-CHBE from COBE by E. coli CCZU-A13 whole-cells. The yield of ( R )-CHBE (>99% e.e. ) from 800 mM COBE was obtained at 100% in the [Bmim]PF 6 -hydrolyzate (50:50, v/v) media by supplementation of OP-10 (20 mM) and Hp-β-CD (8 mM). In conclusion, an effective strategy for the biosynthesis of ( R )-CHBE was successfully demonstrated.
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FlatChem
·
2026
·
IF 5.7
Jian Yang,Zhixiang Liu,Xiang Liu
We report a green approach of preparing cationic surfactant with starch. • None of any organic solvent is used during the whole procedure. • The cationic surfactant differs entirely with conventional one in structure. Renewable carbohydrates provided abundant resources for the preparation of carbon dots (CDs), which could serve as a starting material for synthesis of fine chemicals. In this work, soluble starch was first formulated into an aqueous dispersion and then converted into starch-derived CDs (designated as SCDs) via hydrothermal treatment. Subsequently, SCDs were facilely and efficiently modified with n -dodecylamine in an aqueous medium (the modified product was denoted as SCDs-C12). Experimental results demonstrated that a dilute solution of SCDs-C12 reduced the surface tension of water from 72.0 to 31.9 mN·m −1 (25 °C), and its surface activity was comparable to that of some novel gemini surfactants. Additionally, the positively charged SCDs-C12 exhibited excellent performance in inhibiting the growth of E. coli , with a minimum inhibitory concentration of only 0.05 mg·mL −1 , outperforming many previously reported CD-based materials. In summary, this work developed an environmentally friendly and green strategy for the fabrication of multifunctional cationic surfactants. Download: Download high-res image (74KB) Download: Download full-size image
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APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2016
·Vol. 181
·期 4
·1347-1359
·
IF 1.606
Dai Yong,Huan Bin,Zhang Hai-Sheng,He Yu-Cai
To increase the biocatalytic activity of Escherichia coli CCZU-T15 whole cells, choline chloride/glycerol ([ChCl][Gly]) was firstly used as biocompatible solvent for the effective biotransformation of ethyl 4-chloro-3-oxobutanoate (COBE) into ethyl ( S )-4-chloro-3-hydroxybutanoate [( S )-CHBE]. Furthermore, L-glutamine (150 mM) was added into [ChCl][Gly]–water ([ChCl][Gly] 12.5 vol%, pH 6.5) media instead of NAD + for increasing the biocatalytic efficiency. To further improve the biosynthesis of ( S )-CHBE (>99 % e.e. ) by E. coli CCZU-T15 whole cells, Tween-80 (7.5 mM) was also added into this reaction media, and ( S )-CHBE (>9 % e.e. ) could be effectively synthesized from 2000 and 3000 mM COBE in the yields of 100 and 93.0 % by whole cells of recombinant E. coli CCZU-T15, respectively. TEM image indicated that the cell membrane was permeabilized and lost its integrity and when the cell was exposed to [ChCl][Gly]–water media with Tween-80. Clearly, this bioprocess has high potential for the effective biosynthesis of ( S )-CHBE (>99 % e.e. ).
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2021
·
IF 19.503
Zexiao Zheng,Irene M.C. Lo
Pharmaceuticals and personal care products (PPCPs) and Escherichia coli ( E. coli ) are ubiquitous in sewage posing adverse effects on both ecosystems and human health. Herein, we propose a multifunctional photoelectrochemical (PEC) system to simultaneously degrade PPCPs, disinfect E. coli , and produce H 2 . To this end, an optimized MoS 2 @BL-BiVO 4 photoanode with reduced bulk and surface charge recombination was synthesized, exhibiting a photocurrent density of 2.21 mA/cm 2 at 1.0 V vs. Ag/AgCl in actual sewage, 8.1 times that of P-BiVO 4 . The MoS 2 @BL-BiVO 4 photoanode achieved complete degradation of 2 ppm benzophenone-3 and inactivation of E. coli in sewage with 89.32 μmol H 2 evolution at 1.0 V vs. Ag/AgCl in 30 min. Chloride ions in the sewage played a critical role in the PEC system: they were activated to become chloride-based radicals ( Cl, ClO) for sewage treatment and worked as hole scavengers to increase H 2 evolution. Natural organic matters in the sewage played a dominant role in impeding the PEC reactions because they can quench the reactive species and were adsorbed onto the photoanode’s surface to block charge separation. The PEC system shows good efficiency when degrading various PPCPs, and excellent reusability and stability, giving it great practicality.
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