APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2024
·Vol. 108
·期 1
·1-12
·
IF 3.9
Chen Qianlin,Wang Bin,Pan Li
Abstract In this study, we successfully applied the strategy of combining tandem promoters and tandem signal peptides with overexpressing signal peptidase to efficiently express and produce γ-glutamyl peptidase (GGT) enzymes (BsGGT, BaGGT, and BlGGT) from Bacillus subtilis , Bacillus amyloliquefaciens , and Bacillus licheniformis in Bacillus subtilis ATCC6051Δ5. In order to avoid the problem of instability caused by duplicated strong promoters, we assembled tandem promoters of different homologous genes from different species. To achieve resistance marker-free enzyme in the food industry, we first removed the replication origin and corresponding resistance marker of Escherichia coli from the expression vector. The plasmid was then transformed into the B. subtilis host, and the Kan resistance gene in the expression plasmid was directly edited and silenced using the CRISPR/Cas9n-AID base editing system. As a result, a recombinant protein expression carrier without resistance markers was constructed, and the enzyme activity of the BlGGT strain during shake flask fermentation can reach 53.65 U/mL. The recombinant BlGGT was immobilized with epoxy resin and maintained 82.8% enzyme activity after repeated use for 10 times and 87.36% enzyme activity after storage at 4 °C for 2 months. The immobilized BlGGT enzyme was used for the continuous synthesis of theanine with a conversion rate of 65.38%. These results indicated that our approach was a promising solution for improving enzyme production efficiency and achieving safe production of enzyme preparations in the food industry. Key points
• Efficient expression of recombinant proteins by a combination of dual promoter and dual signal peptide.
• Construction of small vectors without resistance markers in B. subtilis using CRISPR/Cas9n-AID editing system.
• The process of immobilizing BlGGT with epoxy resin was optimized.
研究领域:
微生物学
·
食品科学
·
分子生物学
✓ 已验证
DOI
PubMed
高影响因子
Food Analytical Methods
·
2025
·
IF 3
Yuan Haiyue,Wang Jiafu,Fu Jiqiang,Wang Jishi,Zhang Yanwei,Geng Yue,Li Bei,He Zeying
A multiresidue method for simultaneously detecting 523 pesticides and metabolites in vegetables using ultra-high-performance liquid chromatography and gas chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS and GC–MS/MS) was developed and rigorously validated for accuracy, precision, linearity, quantification limits, and matrix effects. The validated method was applied to analyze 300 vegetable samples from Shandong province, China, collected in 2023. Results showed the detection of 94 pesticides overall, with a detection rate of 31.67% and a 4.00% exceedance rate of maximum residue limits. Leafy vegetables exhibited the highest detection rate, and insecticides were commonly used in vegetable production. Thiamethoxam was the most frequently detected pesticide. Some banned and restricted pesticides were found at low levels. Celery, Chinese cabbage, tomato, cucumber, eggplant, sweet pepper, and spinach showed the highest frequency of multiple residues. In several rare cases, potential risks to adults and children were identified, highlighting the need for continuous monitoring of pesticide residues to ensure consumer safety.
研究领域:
食品科学
·
环境科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Food Analytical Methods
·
2023
·Vol. 16
·期 9
·1468-1476
·
IF 2.9
Yang Yi,Shi Kaicun,Xu Shufang,Tian Yu,Huang Hong,Cai Xiaoli,Liu Zhimin,Xu Zhigang,Zhang Fengmei,He Pei,Liu Chunbo,Si Xiaoxi
Vitamin B3 is an essential vitamin that the human body cannot synthesize in sufficient amounts. Thus, it must be supplemented through food and medicine. The vitamin B3 content of foods and drugs must therefore be determined to identify its main sources. However, vitamin B3 is a strongly polar substance, and its detection in complex actual samples has certain challenges. In this study, a double column tandem method was established for the determination of vitamin B3 in fruit and drug samples. The chromatographic retention of the vitamin was investigated using different chromatographic single-column and double-column tandem models. The best separation and determination effect was obtained under a dual-column tandem mode consisting of a C18 short column and a HILIC column. The chromatographic conditions for vitamin B3 detection were as follows: 10:90 (v:v) acetonitrile–0.1% acetic acid water solution mobile phase, 30 ℃ column temperature, 0.4 mL/min flow rate, and 262 nm detection wavelength. This method was used to detect vitamin B3 in three fruits and two drugs. The detected content ranged between 1.50×10 2 and 1.35×10 3 mg/kg, and the recovery for spiked samples was 85–102%. This high performance liquid chromatography with two columns tandem can effectively determine vitamin B3. Graphical Abstract
研究领域:
分析化学
·
营养学
✓ 已验证
产品关联
DOI
高影响因子
Separations
·
2023
·Vol. 10
·期 4
·231
·
IF 2.6
Chang-Seob Seo,Hyeun-Kyoo Shin
Gongjindan (GJD) is a traditional Korean medicine consisting of four herbal medicines and two animal-derived medicines, and is taken as a tonic in Republic of Korea. In this study, the goal was to develop and validate a simultaneous analytical method to quantify eight compounds in commercially available GJD samples using high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography with tandem mass spectrometry (UPLC–MS/MS), and gas chromatography with tandem mass spectrometry (GC–MS/MS) systems. In HPLC and UPLC–MS/MS, seven components (gallic acid, 5-(hydroxymethyl)furfural, morroniside, loganin, nodakenin, decursin, and decursinol angelate) were separated and quantified using a distilled water–acetonitrile mobile phase system on a Capcell Pak UG80 C18column and an Acquity UPLC BEH C18 column, respectively. Muscone was quantified using GC–MS/MS. The developed assays were validated by evaluating the linearity, limit of detection, limit of quantitation, recovery, and precision. In the regression equations of all compounds, the coefficient of determination was ≥0.9917, showing good linearity. The recovery was 93.70–108.17%, and the relative standard deviation values in the precision test were all <1.50%. Using the developed analysis methods, GJD samples were determined to contain the eight target compounds in concentrations from non-detected to 10.75 mg/g. The analytical assays developed and validated in this study can be used to obtain data for the quality control of commercially available GJDs and for the further expansion of efficacy and clinical studies.
研究领域:
中药学
·
分析化学
·
药理学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2021
·Vol. 8
·期 16
·3863-3870
·
IF 6.569
Yuwei Zhang,Lina Wang,Xiaoxiang Xu
CuBi2O4 and CuWO4 films (2 × 2 cm) on an FTO substrate have been fabricated to construct an all-copper-based oxide tandem cell for solar-driven photoelectrochemical (PEC) water splitting. CuBi2O4 and CuWO4 films are of opposite semiconductivity, and exhibit a large difference in the onset potentials and matched light absorption, making them ideal for a tandem configuration for solar energy conversion. Under optimal conditions, the tandem cell (4 cm2) exhibits a water splitting photocurrent of 0.3 mA without an external bias under simulated solar insolation. The low cost, non-toxicity, good stability and easy manufacture of this copper-based oxide tandem cell warrant promising applications in the field of solar energy conversion.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED BIOCHEMISTRY AND BIOTECHNOLOGY
·
2013
·Vol. 171
·期 7
·1559-1567
·
IF 1.893
Wang Na,Zhang Wei,Zhou Long-Hua,Deng Qing-Feng,Xie Zong-Bo,Yu Xiao-Qi
A facile tandem route to α,β-unsaturated aldehydes was developed by combining the two catalytic activities of the same enzyme in a one-pot strategy for the aldol reaction and in situ generation of acetaldehyde. Lipase from Mucor miehei was found to have conventional and promiscuous catalytic activities for the hydrolysis of vinyl acetate and aldol condensation with in situ formed acetaldehyde. The first reaction continuously provided material for the second reaction, which effectively reduced the volatilization loss, oxidation, and polymerization of acetaldehyde, as well as avoided a negative effect on the enzyme of excessive amounts of acetaldehyde. After optimizing the process, several substrates participated in the reaction and provided the target products in moderate to high yields using this single lipase-catalyzed one-pot biotransformation.
研究领域:
生物化学
·
酶工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2019
·
IF 2.931
Wenzhi Xu,Xue Li,Mengnan Han,Tingting Zhou,Yutao Yang,Wei Li
Hydrazine is extremely harmful to the human body. The leakage of hydrazine is liable to cause potential safety hazards. Here, we reported a new fluorescence probe based on the tandem reaction . The hydrazine-triggered hydrazinolysis-cyclization resulted in the formation of the iminocoumarin. The fluorescence intensity at 522 nm of the probe increased after the reaction with hydrazine. There was a linear relationship between the fluorescence intensity and the concentration of hydrazine (0.14–120.00 μM). The LOD of the probe to N 2 H 4 was 1.36 ppb. Notably, the probe could detect hydrazine in BT474 cells and tap water.
研究领域:
分析化学
·
环境科学
·
生物医学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
·
2020
·Vol. 101
·期 7
·2779-2787
·
IF 2.614
Wenbi Guan,Yingxin You,Jialing Li,Jiaying Hong,Haiying Wu,Yanna Rao
BACKGROUND Penicillic acid (PA) is produced by Aspergillus spp. and Penicillium spp., which are common postharvest and storage fungi of fruits. PA can be of concern for human health because of its toxicity and high fruit consumption by the population. However, no data on PA occurrence in various fruits have yet been reported. A quick, easy, cheap, effective, rugged and safe (QuEChERS) approach for PA determination in various fruits was developed and applied to explore PA incidence in fruits. RESULTS The modified QuEChERS procedure with extraction by ethyl acetate and purification by multi-walled carbon nanotubes (MWCNTs), primary secondary amine (PSA) and octadecyl silane (C18) was established to determine PA in various fruits by high-performance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS). The average recoveries were 72.9–102.2% and relative standard deviations (RSDs) were 1.3–7.9%. A total of 161 fruits samples, including kiwi, apple, peach, grape and mandarin/orange, were collected in southern China. The incidence of PA in fruits was 14.9% and the levels of PA contamination were 0.200–0.596 μg kg −1 . Our results suggested that orange/mandarin, grape and kiwi were favorable matrices for Aspergillus spp. and Penicillium spp. to produce PA, rather than peach and apple. CONCLUSION To the best of our knowledge, this is the first report about PA contamination in various fruits in China. Our study emphasizes the necessity of the current established method, which could be used for continuous monitoring of PA and reducing the health risk to Chinese consumers. © 2020 Society of Chemical Industry
研究领域:
食品安全
·
分析化学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2022
·
IF 9.231
Songyang Yao,Xuening Liu,Yao Fu,Shengyu Guan,Yunjie Liu,Laiqing Yan,Pingli He,Guoshi Liu
Since the global demanding of natural melatonin-enriched milk has been significantly increased in the populations of children and elder, the accurate and quick melatonin detection from milk is urgently required. Thus, the regular methods no longer satisfy this requirement. In the current study, we reported a novel method to extract melatonin from milk for liquid chromatography-tandem mass spectrometry melatonin detection. This novel method was to use cold methanol (-20℃) to precipitate proteins and fat in milk with one step to extract melatonin. Compared to the regular methods, it was devoid of procedures of sample drying, solid phase extraction and sample reconstitution. It could short the extraction time from the regularly 150 min to 60 min/per 24 milk samples. We believe that this novel method provides a possibility to detect large scale of milk samples in relatively short time with more efficiency and less cost compared to the regular method.
研究领域:
分析化学
·
生物医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
GREEN CHEMISTRY
·
2023
·
IF 9.8
Shihao Su,Guojun Lv,Xuyang Zou,Jiangzhang Wang,Chaoyi Zhou,Yan Chen,Jialing Shen,Yangbin Shen,Zhongmin Liu
In the cyclic alkene epoxidation reactions using molecular oxygen as oxidant, aldehyde is generally added as co-oxidant to assist transition metal catalyst to activate the oxygen molecule, oxidizing cyclic alkene and producing the corresponding epoxide; however, the added aldehyde would be converted into byproduct carboxylic acid. Herein, we report the room-temperature tandem conversion of cyclic alkenes into 1,2-diols through the application of byproduct carboxylic acid as a catalyst for epoxide hydration reaction, realizing effective utilization of the byproduct and saving energy consumption. Four kinds of nanosized MnO2 specimens, including α-, β-, δ-, and γ-MnO2, were hydrothermally synthesized and applied as heterogeneous catalysts for the room-temperature tandem conversion of cyclohexene into 1,2-cyclohexanediol using molecular oxygen as oxidant and isobutyraldehyde as co-oxidant. The characterization results demonstrated that the obtained β-MnO2 sample had the maximum Mn4+/Mn3+ ratio of 1.42 and the minimum Oads/OLatt ratio of 0.34, consistent with its least oxygen vacancies evidenced by EPR measurement. Accordingly, the β-MnO2 sample revealed the quickest alkene epoxidation reaction rate and could achieve a 99.2% cyclohexene conversion within 1 h, and meanwhile, a 73.6% 1,2-cycloheanediol yield could be attained within 24 h. A plausible mechanism for the tandem conversion of cyclohexene into 1,2-cyclohexanediol over the β-MnO2 heterogeneous catalyst was proposed and further verified by quenching experiments and DFT calculations. Furthermore, the synthesized β-MnO2 catalyst sample could be reused more than ten times, and meanwhile, the tandem conversion way could be expanded to most of the cyclic alkene substrates, which demonstrated that the β-MnO2 catalyst was an active and stable heterogeneous catalyst for tandem conversion of cyclic alkenes into 1,2-diols.
研究领域:
催化化学
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Xin Kang,Jiancong Liu,Dongxu Wang,Chungui Tian,Honggang Fu
CO 2 hydrogenation to hydrocarbons under high space velocity is crucial for industrial applications, but traditional Fe-based catalysts often suffer from the low activity and poor stability. Herein, we report a new tandem catalyst system combining Pt/TiO 2 catalysts with Fe 3 C catalysts for the direct conversion of CO 2 into C 2 -C 4 hydrocarbons under high space velocity. The Pt/TiO 2 component promotes *CO intermediate production with an enhanced Reverse Water-Gas Shift (RWGS) reaction efficiency, providing a highly reactive species for the Fe 3 C catalyst to achieve Fischer-Tropsch synthesis (FTS). By maximizing the contact interface between the Pt/TiO 2 and Fe-based components through a granule mixing configuration, we achieve significant enhancements in both CO 2 conversion rate (24.0 %) and C 2 -C 4 hydrocarbons selectivity (51.1 %) under the gaseous hourly space velocity (GHSV) of 100000 mL g cat −1 h −1 . Besides, excellent stability is achieved by the tandem catalysts with continuous catalysis for up to 80 h without significant decrease in activity. Through modulation of the reduction states of iron oxide, we effectively tune the composition of Fe-based catalyst, thereby tailoring the product distribution. Through this work, we not only offer a promising avenue for reducing CO 2 for efficient CO 2 utilization but also highlight the importance of catalyst design in advancing sustainable chemical synthesis.
研究领域:
催化化学
·
环境科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 151
·期 9
·2638-2646
·
IF 3.186
Li Xiao,Qin Tingting,Li Liusha,Wu Bo,Lin Tiejun,Zhong Liangshu
Abstract A green route for one−pot synthesis of acetals by tandem hydroformylation−acetalization of olefins using supported Rh−based catalysts was developed. Experimental results demonstrated that suitable Rh loading (1 wt%) with appropriate reaction temperature (120 °C) and reaction time (8 h) were favorable for the formation of acetals, and a high acetals selectivity of 94.6% was achieved. More importantly, the selectivity to valuable linear products was enhanced in this tandem catalysis. Based on the catalytic mechanism study, highly dispersed RhO x nanoparticles and abundant acid sites on the supports were responsible for the hydroformylation and acetalization, respectively. Graphical abstract One-pot synthesis of acetals directly from olefins with high selectivity was achieved over heterogeneous bifunctional catalysts via tandem hydroformylation-acetalization.
研究领域:
化学工程
·
催化科学
✓ 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）