Food Bioscience
·
2021
·
IF 4.24
Bo Zhang,Li Chen,Jie-Yi Jin,Na Zhong,Xue Cai,Shu-Ping Zou,Hai-Yan Zhou,Zhi-Qiang Liu,Yu-Guo Zheng
: As the key precursor of coenzyme A synthesis in vivo , D-pantothenic acid plays an important role in maintaining biological function, which is widely applied in the food , pharmaceutical, and cosmetic industries. At present, it was mainly produced by chemical methods, with serious environmental pollution, therefore, it is urgent to develop an economical, practical, and environmentally friendly biological fermentation method based on microbial chassis cells. Herein, based on our previously developed D-pantothenic acid producing strains, we obtained higher yielding D-pantothenic acid producing strains by systematic metabolic engineering . First, according to the results of CRISPRi experiments, lpd were overexpressed, disrupted the non-PTS (non-phosphoenolpyruvate-pyruvate transport system) as well as enhanced the PTS (phosphoenolpyruvate-pyruvate transport system) allowing precursor accumulation. Subsequently, based on the analysis of metabolic intermediates , the pyruvate bypass pathway was blocked as well as the (R)-pantothenic acid pathway was further enhanced, increasing the titer of D-pantothenic acid to 4.60 g/L. Finally, the organic acid and branched-chain amino acid synthesis pathways were blocked, and in order to accelerate the synthesis of acetolactate and the output of D-pantothenic acid, heterologous acetolactate synthase and pantothenate transfer protein were introduced, which significantly increased the yield of D-pantothenic acid, reach to 6.33 g/L. The final strain in a 5 L bioreactor produced 32.32 g/L D-pantothenic acid with a productivity of 2.33 g/L/h and the high-yielding strain provides an effective platform for biological fermentation to produce D-pantothenic acid.
研究领域:
生物技术
·
代谢工程
·
微生物学
·
发酵技术
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Xianbao Li,Shunjing Luo,Yaqin Hou,Yunfei Liu,Xiuting Hu,Chengmei Liu
This study aimed to reveal the effect of corn oil on formation of complex between rice starch and fatty acids, including lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0) and stearic acid (C18:0). The RVA, XRD, DSC and CLSM analysis confirmed formation of starch-fatty acid complex but the starch-triglyceride complex was not detected. The addition of triglyceride promoted formation of starch-C16:0 and starch-C18:0 complexes, which might be due to more leached amylose induced by oil. However, triglyceride inhibited formation of starch-C12:0 and starch-C14:0 complexes, which might be due to high solubility of C12:0 and C14:0 in oil. In conclusion, the effect of triglyceride on formation of starch-fatty acid complex depended on the chain length of fatty acids.
研究领域:
食品科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF ANALYTICAL CHEMISTRY
·
2015
·
IF 0.754
Liang HAO,Da-Peng WU,Ya-Feng GUAN
The method of micro-pressurized liquid extraction (μ-PLE) coupled with gas chromatography-mass spectrometer (GC-MS) for analysis of 4 dicarboxylic acids (DCAs, including malonic acid, succinic acid, glutaric acid, and adipic acid) in fine atmospheric particles was developed. PM 2.5 filter sample was extracted by μ-PLE at a pressure of 8 MPa and temperature of 80 °C using methanol as extraction solution. After two static 5-min extractions and a rinsing step with 100 μL methanol, about 500 μL of extraction solution was obtained. The extraction solution was then blown to dry with high purity nitrogen and submitted to a silylation reaction at 60 °C for 30 min. After internal standard (IS) was added, the derivatization solution was directly injected for GC-MS analysis. For quantification of 4 normally DCAs in fine atmospheric particles, the calibration curve was obtained with a good linear relationship in the range of 0.2–20 ng μL −1 . The limits of quantification (LOQs, S/N = 10) were in the range of 0.15–0.47 ng m −3 . The relative recoveries were between 92% and 122% with the RSDs between 2.6% and 11.8% for spiked filter samples. The method developed here was used to determine malonic acid, succinic acid, glutaric acid, and adipic acid in real PM 2.5 samples collected from Xinghai Bay of Dalian city, and the results were determined to be 64.6, 50.0, 41.8 and 20.2 ng m −3 , respectively.
研究领域:
分析化学
·
环境科学
·
大气化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICA CHIMICA ACTA
·
2020
·
IF 5.977
Weitao Xu,Huaming Feng,Weiwei Zhao,Chunhua Huang,Carl Redshaw,Zhu Tao,Xin Xiao
A new fluorescent chemosensor comprised of cucurbit[8]uril (Q[8]) and acridine hydrochloride (AC) has been designed and utilized for the recognition of amino acids . The AC was encapsulated by the Q[8] cavity and formed a 1:2 host-guest inclusion complex both in solution (aqueous) and in the solid-state. Whilst free AC is known to be strongly fluorescent, this strong fluorescence was quenched in the inclusion complex Q [8]-AC. This non-fluorescent complex Q[8]-AC was capable of serving as a fluorescence “off-on” probe, and was able to recognize either L -Phe or L -Trp via the competitive interaction between L -Phe or L -Trp. Moreover, the pH responsive nature of the probe allowed for the detection of basic amino acids, namely L -Arg, L -His, or L -Lys). As a result, a fluorescence method for the detection of five amino acids using a single system has been developed.
研究领域:
化学
·
分析化学
·
材料科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Wanqi Xu,Congcong Ni,Ning Deng,Xin Huang
In persulfate-based advanced oxidation processes (PS-AOPs), sulfate radicals (SO 4 •- ) have been recognized to play more important roles in inducing bromate (BrO 3 − ) formation rather than hydroxyl radicals (HO • ) because of the stronger oxidation capacity of the former. However, this study reported an opposite result that HO • indeed dominated the formation of bromate instead of SO 4 •- . Quenching experiments were coupled with electron paramagnetic resonance (EPR) detection and chemical probe identification to elucidate the contributions of each radical species. The comparison of different thermal activated persulfates (PDS and PMS) demonstrated that the significant higher bromate formation in HEAT/PMS ([BrO 3 − ]/[Br − ] 0 = 0.8), as compared to HEAT/PDS ([BrO 3 − ]/[Br − ] 0 = 0.2), was attributable to the higher concentration of HO • radicals in HEAT/PMS. Similarly, the bromate formation in UV/PDS ([BrO 3 − ]/[Br − ] 0 = 1.0), with a high concentration of HO • , further underscored the dominant role of HO • . As a result, we quantified that HO • and SO 4 •- radicals accounted 66.7% and 33.3% for bromate formation. This controversial result can be reconciled by considering the critical intermediate, hypobromic acid/hypobromate (HOBr/BrO − ), involved in the transformation of Br − to BrO 3 − . HO • radicals have the chemical preference to induce the formation of HOBr/BrO − intermediates (contributing ∼ 60%) relative to SO 4 •- radicals (contributing ∼ 40%). This study highlighted the dominant role of HO • in the formation of bromate rather than SO 4 •- in PS-AOPs and potentially offered novel insights for reducing disinfection byproduct formation by controlling the radical species in AOPs.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ANIMAL SCIENCE
·
2020
·Vol. 98
·期 10
·
IF 2.092
Sun Mingfa,Zhao Jingpeng,Wang Xiaojuan,Jiao Hongchao,Lin Hai
The supplementation of dietary limiting amino acids (AA) with crystalline AA makes the use of low-protein diets an option in poultry production. The differing absorption rates of crystalline and protein-bound AA may lead to temporally imbalanced AA in the postabsorptive period. In this study, two experiments were conducted to evaluate the effect of encapsulated L-lysine-HCl (L-Lys-HCl) and DL-methionine (DL-Met) on the laying performance of hens. In exp. 1, a total of 135 forty-seven-wk-old Hy-Line Brown hens were subjected to three dietary treatments for 8 wk: basal diet supplemented with 0.14% L-Lys-HCl and 0.17% DL-Met to satisfy the NRC (1994) total Lys and Met recommendation (control) and basal diet supplemented with encapsulated L-Lys-HCl and DL-Met at the levels of 60% (60CLM, 0.084% L-Lys-HCl and 0.102% DL-Met) or 80% of control (80CLM, 0.112% L-Lys-HCl and 0.136% DL-Met), respectively. In exp. 2, 24 fifty-five-wk-old Hy-Line Brown hens were individually reared in cages and subjected to the same treatments as in exp. 1. The plasma concentrations of free AA and nitrogen metabolites were measured 2, 4, and 6 h after fed. The results showed that dietary AA treatment had no significant influence on body weight (BW), feed intake, laying rate, egg weight, egg mass, or feed efficiency. The expression levels of AA transporters CAT-1, y+LAT1, b0,+AT, B0AT, rBAT, EAAT3, and PepT1 in the duodenum, jejunum, and ileum were not influenced (P > 0.05) by dietary treatment. There was an interaction of dietary AA treatment and time (P < 0.05) and the 80CLM hens exhibited higher concentrations of Lys (P < 0.05) than the controls at 2-h time point. In contrast, plasma Met concentration was not influenced (P > 0.05), while Cys was reduced in the 60CLM hens at every time point. The 80CLM hens had higher taurine concentrations than those receiving the control diet at every postprandial time point. In conclusion, these findings demonstrate that by using encapsulated form, the supplemental levels of synthetic L-Lys-HCl and DL-Met can be effectively reduced by approximately 20% with no negative effect on laying performance. The result suggests that encapsulated Lys and Met may ameliorate the postabsorptive AA balance and contribute to the reduced dietary AA supplemental levels.
研究领域:
动物营养学
·
家禽科学
·
氨基酸代谢
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CRYSTAL GROWTH & DESIGN
·
2022
·
IF 4.01
Xiaojuan Wang,Qihuang Xie,Di Gao,Xin Ye,Zongwu Deng,Hailu Zhang
The structural resemblance strategy is an often-employed principle to guide the discovery of novel pharmaceutical cocrystals and salts. Here, baricitinib (BAR) was selected as a model compound due to the existence of abundant heterocyclic nitrogen sites (proton acceptor sites) to form crystalline complexes with four structurally similar and pharmaceutically acceptable C4-dicarboxylic acids, maleic acid (MAL), fumaric acid (FUM), succinic acid (SUC), and l-tartaric acid (TAR). Crystal structures, intermolecular interactions, and physicochemical properties of each resulting form were analyzed to demonstrate the similarity and diversity. BAR–MAL and BAR–TAR are two salts with stoichiometric ratios of 2:2 and 2:1, respectively. BAR–FUM and BAR–SUC are isostructural cocrystals with a stoichiometric ratio of 1:0.5. All of these new solid-state forms demonstrated excellent phase stability against hydration, reduced hygroscopicity, and slight solubility improvements, supporting their usage as alternative forms of BAR for generic drug development.
研究领域:
药学
·
结晶学
✓ 已验证
DOI
高影响因子
Greenhouse Gases-Science and Technology
·
2023
·Vol. 13
·期 6
·814-828
·
IF 2.2
Yuhang Yang,Wenxiu Li,Zhiwei Xun,Zhenwei Yi,Tao Wang,Zitao Yu,Yan Huang,Yongzheng Gu
In light of the current situation where the utilization of calcium carbide slag yields low profits but holds significant potential for reducing carbon emissions, ammonium acetate was employed to leach calcium carbide slag. It also played a crucial role in regulating the products of indirect carbon dioxide carbonation when mixed with glycine and lye. Ammonium acetate's significance underscores its dual role in both the leaching and carbonation processes. This process yielded calcium carbonate with particle sizes smaller than 100 nm, with a purity of 98% and a single vaterite phase. The calcium carbide residue demonstrated an impressive CO 2 uptake rate of 23.5%. Ammonium acetate exhibited an efficiency of 79.2% as a leaching agent. The ammonium acetate method demonstrated enhanced environmental friendliness and facilitated a more efficient carbon uptake rate of 23.5% compared to conventional indirect methods. Furthermore, the addition of lye, glycine, and ammonium acetate effectively extended the nucleation time of the calcium carbonate crystals and induced the formation of more vaterite intermediates with smaller particle sizes. The influence mechanism of compound additives on the carbonation reaction was revealed through kinetic analysis and molecular dynamics. This innovative approach offers a promising avenue for simultaneously treating solid waste and reducing CO 2 emission. © 2023 Society of Chemical Industry and John Wiley & Sons, Ltd.
研究领域:
环境科学
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Environmental Science and Technology
·
2024
·
IF 3
Yi L.,Li W.,Bu H.,Yin W.,Deng H.,Wu J.
Humic acid, nitrate, and sulfate in the environment may affect the performance of abiotic and biotic zero-valent iron (Fe 0 ) on the remediation of heavy metal-contaminated soil. In this study, a synergistic system combining Fe 0 and microbes was established to remediate Cr(VI)-contaminated soil at low and relatively high concentrations of humic acid, nitrate, and sulfate with Fe 0 as a control. In the abiotic Fe 0 system, humic acid inhibited Cr(VI) removal by occupying iron surface with its oxygen-containing functional groups and generating iron or calcium-containing precipitates on Fe 0 surface. However, microbes could effectively degrade humic acid to promote their growth, iron corrosion, and secondary mineral production for enhanced Cr(VI) removal. As for nitrate, it showed slightly promoted effect on iron corrosion in abiotic Fe 0 , but competed with Cr(VI) for cathodic hydrogen from iron corrosion for biological denitrification and thereby significantly inhibited Cr(VI) removal in biotic Fe 0 . Different from denitrification, hydrogenotrophic desulfuration promoted active mineral generation such as iron sulfide and green rust owning to biomineralization. These minerals were beneficial for Cr(VI) adsorption and reduction. Thus, in the biotic Fe 0 system, the presence of 10 mmol kg −1 sulfate led to a higher Cr(VI) removal of 79.5% as compared to that of 48.4% in the system without sulfate. The results indicated that it is necessary to deeply understand the potential effects of organic substrates and electron acceptors on Cr(VI) removal in soil when using abiotic and biotic Fe 0 before their application.
研究领域:
环境科学
·
土壤修复
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2024
·
IF 4.7
Yingdan Ye,Han Wang,Yibin Zhang,Huaiyuan Zhao,Weichen Du,Ping Chen,Zhaoyin Hou
Chemical upcycling of end-of-life plastics is an economically and environmentally feasible way to tackle plastics crisis. Among them, methanol alcoholysis of polylactic acid (PLA) is a promising approach, which can produce methyl lactate (MLA) that can be further converted to lactide to achieve a sustainable development. In this work, a series of WO x /ZrP catalysts with WO x active sites in low coverage and high surface area were synthesized via anchoring WO x species on the surface of zirconium phosphate (ZrP). Characterizations indicated that the strong interaction between WO x and ZrP promoted the formation of WO x active sites in low coverage. In particular, 10 %WO x /ZrP catalyst was highly active and stable for the alcoholysis of PLA plastics under mild conditions due to the abundant WO x active sites and strong acidity. The yield of MLA over 10 %WO x /ZrP catalyst reached 94.5 % within 4 h at 160 °C, which was superior to the performance of traditional solid acids ( α -ZrP, HZSM-5, H β and Amberlyst-45). In addition, 10 %WO x /ZrP was versatile for the alcoholysis of discarded PLA-based products and could be recycled at least five times. The prominent performance of 10 %WO x /ZrP catalyst and the possible reaction mechanism were discussed.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Jian Yang,Daoming Chen,Meifang Cao,Xueqing Qiu,Xinping Ouyang
The catalytic dehydration of bio-derived lactic acid into acrylic acid is one of the research hotspots in the field of green chemical industry, but the selectivity of acrylic acid and the stability of catalyst still face great challenges. In this work, a modified Hβ zeolite catalyst was prepared by sequential nitric acid treatment and Rb ion-exchange for the gas phase dehydration of lactic acid to prepare acrylic acid. The nitric acid treatment increased the content of Lewis acid sites together with the decrease of the content of Bronsted acid sites, which enhanced the dehydration and hindered the decarboxylation/decarbonylation of lactic acid. Consequently, the selectivity of acrylic acid was improved. The Rb ion-exchange not only significantly decreased the density of acidic sites but also regulated the density of basic sites of the catalyst. The optimal 0.1NA-6.8Rb/Hβ catalyst treated by 0.1 mol/L of nitric acid and 6.8 wt% of Rb ion-exchange contributed to a 99.28 % conversion of lactic acid and 76.72 % yield of acrylic acid. The catalyst showed a better stability and was easy to regenerate, maintaining 87.35 % conversion of lactic acid and 62.49 % yield of acrylic acid, respectively, after two cycles of consecutive 48 h reaction.
研究领域:
绿色化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
·
2020
·Vol. 56
·期 1
·441-451
·
IF 2.773
Geng Yang,Rui Wang,Jing-Rong Gao,Debao Niu,Jian Li,Qing-Hui Wen,Xin-An Zeng
Summary The effect of moderate pulsed electric fields (MPEF) strength on autolysis of Saccharomyces cerevisiae was evaluated in this study. After exposure to MPEF with intensity of 7 kV cm −1 for 4 ms, the integrity of the cell wall was obviously destroyed and the inactivation of S. cerevisiae reached 99.43%. During the subsequent 42-h autolysis process, the release of free α-amino nitrogen of MPEF-treated cells, as well as extracellular protease activity, was significantly ( P < 0.05) higher than that of untreated cells. Moreover, exposure to 7 kV cm −1 led to an increase of the total amino acid of 149.36%. In particular, the content of aspartic acid and glutamic acid which are important umami flavour precursors increased by 232.55% and 209.40%, respectively. These results indicate that MPEF will be an effective method to accelerate autolysis of S. cerevisiae for obtaining high-quality yeast extract as flavour enhancers and nutrition supplements.
研究领域:
食品科学
·
微生物学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）