CATALYSIS COMMUNICATIONS
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2013
·
IF 2.915
Hong-De Yan,Qun Zhang,Zhao Wang
A lipase from Aspergillus oryzae WZ007 exhibited high esterification activities toward a series of short-chain acids and alcohols. Moreover, it displayed a strong tolerance for high substrate concentration of up to 2.0 M and presented a highest initial rate of 276 mmol·L − 1 ·h − 1 at this concentration. After a reaction time of 48 h, the conversion rates of acids were higher than 80% for the synthesis of a majority of heptanoic acid esters, some octanoic acid esters and n -propyl hexanoate. These results implied that A. oryzae WZ007 lipase was a promising biocatalyst in the production of flavor esters.
研究领域:
生物化学
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食品科学
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产品关联
DOI
高影响因子
Food Bioscience
·
2024
·
IF 4.8
Yue Dai,Xiaoxiao Li,Zhengyu Jin,Yuxiang Bai
Improving substrate utilization is crucial for industrial conversion of starch. The introduction of pullulanase in cyclodextrin (CD) production has improved substrate utilization. However, complete utilization of debranched starches has not been achieved, mainly due to the retrogradation of debranched starches and the inhibitory effect of CDs on pullulanase during the catalytic reaction. This study aimed to establish an efficient CD preparation system by regulating the substrate concentration and reaction temperature. A Bacillus thermoleovorans pullulanase (BtPul) was selected for investigation of its interaction with CDs through inhibition pattern assays, fluorescence spectroscopy, and molecular docking. Results clarified that CDs inhibited BtPul, with α-CD showing the highest inhibition, followed by β-CD and γ-CD. γ-CD inhibited BtPul through a mixed mode of competitive and noncompetitive inhibition, while the other CDs inhibited BtPul competitively. When pullulan was used as the substrate, increasing the substrate concentration weakened the inhibitory effect of CDs to some degree, while changes in reaction temperature only had a minor contribution. When BtPul and β-CGTase collaboratively converted 30% (w/v) starch substrate, an increase in reaction temperature improved the conversion rate of β-CD from 67.6% to 86.8%. Optimization of substrate concentration showed that high concentration starch substrate had an adverse effect on CDs yield due to retrogradation. The optimal yields of α-CD and β-CD produced by BtPul and α-/β-CGTases were 55.7% and 90.3%, respectively. This study provides a reliable method and reference for the efficient conversion of starch into CDs.
研究领域:
生物化学
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食品科学
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工业微生物学
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DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Mingxin Lv,Liyuan Huai,Guoxin Chen,Xi Zhao,Chunlin Chen,Shenghu Zhou,Jian Zhang
Controlling the selective activation of one or some functional groups as desired is still a challenge in hydrogenation, especially at high substrate concentrations. Herein, Pd-MgO interfaces over Al 2 O 3 were finely regulated for efficiently selective hydrogenation of furan ring in 5-hydroxymethylfurfural (HMF) to produce 5-hydroxymethyltetrahydro-2-furaldehyde (5-HMTHFF) or total hydrogenation to 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF), also inhibiting side reaction. The Pd-MgO/Al 2 O 3 with 12.0 wt% of MgO selectively hydrogenates the furan rings with a 5-HMTHFF yield of 82.4 % while that with 2.0 wt% of MgO totally hydrogenates HMF with a DHMTHF yield of 96.2 % at high substrate concentrations (400 mM). Characterizations and DFT calculations demonstrated that oligomeric MgO species suppress the agglomeration of Pd nanoparticles and strengthen HMF adsorption, consequently promoting total hydrogenation. Furthermore, Pd δ+ -MgO 1-x sites between the crystallized MgO and Pd metal favored tilted adsorption on the interface and weakened the activation of the C O bond, consequently selectively producing 5-HMTHFF.
研究领域:
化学工程
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催化科学
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材料科学
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产品关联
DOI
高影响因子
ChemCatChem
·
2022
·Vol. 14
·期 13
·e202200120
·
IF 5.497
Hongmei Fu,Haijun Chen,Beibei Gao,Tianliang Lu,Yunlai Su,Lipeng Zhou,Meijiang Liu,Hongji Li,Xiaomei Yang
Graphical Hydrodeoxygenation and reductive etherification of biomass-derived aldehydes were realized on the same Pd/TiO 2 photocatalyst via photocatalytic transfer hydrogenation using aliphatic alcohols as hydrogen donor, and the selectivity was easily switched by the substrate concentration. The development of selectivity control strategies based on external operational conditions without modification of catalyst is an attractive but challenging issue in photocatalysis. Herein we reported the substrate concentration-switched selectivity in photocatalytic transfer hydrogenation of biomass-derived aromatic aldehydes. With the same catalyst, hydrodeoxygenation was realized at low aldehyde concentration and reductive etherification was realized at high aldehyde concentration. Mechanistic studies revealed that the substrate concentration affected the electron density on catalyst, thus controlled the initial reduction of formyl group and types of intermediates. Competitive adsorption of these intermediates on the catalyst affected hydrogenolysis of C−O bonds in the later stage. This method is easy to handle, and achieved selective hydrogenation of diverse bio-based aldehydes to corresponding deoxygenated products and unsymmetric ether products as potential fuel additives under mild conditions. This work sheds light on the effect of substrate concentration on the selectivity in photocatalysis.
研究领域:
催化
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化学工程
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材料科学
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可再生能源
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DOI
高影响因子
ORGANIC PROCESS RESEARCH & DEVELOPMENT
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2022
·
IF 3.858
Jianjiong Li,Shanshan Yu,Yingang Wang,Peiyuan Yao,Qiaqing Wu,Dunming Zhu
(S)-2-Aminobutane, d-alanine, and d-homoalanine are important intermediates for the production of various active pharmaceutical ingredients and food additives. The preparation of these small chiral amine or amino acids with high water solubility still demands searching for efficient methods. In this work, we identified an ω-transaminase (ω-TA) from Sinirhodobacter hungdaonensis (ShdTA) that catalyzed the kinetic resolution of racemic 2-aminobutane at a concentration of 800 mM using pyruvate as the amino acceptor, leading to the simultaneous isolation of enantiopure (S)-2-aminobutane and d-alanine in 46% and 90% yield, respectively. In addition, (S)-2-aminobutane (98% ee) and d-homoalanine (99% ee) were isolated in 45% and 93% yield, respectively, in the kinetic resolution of racemic 2-aminobutane at a concentration of 400 mM coupled with deamination of l-threonine by threonine deaminase. We thus developed a biocatalytic process for the practical synthesis of these valuable small chiral amine and d-amino acids.
研究领域:
生物催化
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有机化学
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药物化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Weipeng Song,Junhua Zhang,Yong Sun,Rui Zhang,Lincai Peng,Huai Liu
Functionalizing biomass-derived furanic chemicals is of great importance towards biorefinery processes but challenging, especially working at elevated substrate concentrations. We herein report the intervention of 1,4-dioxane co-solvent availably to catalyze hydroxymethylation of furfuryl alcohol (FA) in formalin over Hβ zeolite, giving high yield to 2,5-dihydroxymethylfuran (DHMF), a versatile building block. Impressively, the facilitating effect of 1,4-dioxane on DHMF production became more pronounced with increasing FA feeding concentration, and the yield raised from 19.5 % to 67.8 % from a high FA concentration of 10 wt%. The 1,4-dioxane served not only as a catcher of formaldehyde hydrate to access substrate FA, but also as a shield to restrain undesirable condensation side-reactions. The developed protocol demonstrated an excellent universality in boosting the hydroxymethylation of electrondrawing-group-free furanic molecules (e.g., furan, 2-methylfuran). The understanding of these solvation effects can be employed to effectively manipulate and improve the hydroxymethylation of furanic compounds.
研究领域:
化学工程
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催化
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绿色化学
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生物炼制
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产品关联
DOI
高影响因子
Green Synthesis and Catalysis
·
2025
·
IF 6.3
Mengqian Song,Yu Li,Jinhui Feng,Shuhong Mao,Peiyuan Yao,Qiaqing Wu,Dunming Zhu
Chiral β-amino alcohols represent a significant structural motif in many biologically active molecules. Developing an efficient biocatalytic method for synthesizing chiral β-amino alcohols with structural diversity is highly desirable. In this study, enzymatic hydroxymethylation of aryl-aliphatic aldehydes by benzaldehyde lyases (BALs) enabled the synthesis of α-hydroxymethyl ketones at high substrate loadings (200 mmol/L - 300 mmol/L). And the reductive amination of diverse α-hydroxymethyl ketones by amine dehydrogenases (AmDHs) was conducted for synthesizing chiral β-amino alcohols in high isolated yields (60 %-79 %). Furthermore, a one-pot, two-step enzymatic process involving BAL-catalyzed hydroxymethylation of aldehydes and subsequent AmDH-catalyzed reductive amination was developed, enabling the synthesis of aromatic, aliphatic and aryl-aliphatic ( S )-β-amino alcohols from corresponding aldehydes in good to excellent isolated yields (56 %-96 %) and excellent enantioselectivity (>99 % ee ). The practical utility of this methodology was further demonstrated through the synthesis of key intermediates for antiviral drug Telaprevir or ATP competitive ERK inhibitor BVD-523.
研究领域:
有机化学
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生物催化
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酶学
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药物化学
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合成生物学
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不对称合成
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DOI
高影响因子
ENGINEERING IN LIFE SCIENCES
·
2021
·Vol. 22
·期 1
·40-53
·
IF 2.678
Yingying Xu,Jie Ren,Wei Wang,An-Ping Zeng
Glycine cleavage system (GCS) plays a central role in one-carbon (C1) metabolism and receives increasing interest as a core part of the recently proposed reductive glycine pathway (rGlyP) for assimilation of CO 2 and formate. Despite decades of research, GCS has not yet been well understood and kinetic data are barely available. This is to a large degree because of the complexity of GCS, which is composed of four proteins (H, T, P, and L) and catalyzes reactions involving different substrates and cofactors. In vitro kinetics of reconstructed microbial multi-enzyme glycine cleavage/synthase system is desired to better implement rGlyP in microorganisms like Escherichia coli for the use of C1 resources. Here, we examined in vitro several factors that may affect the rate of glycine synthesis via the reverse GCS reaction. We found that the ratio of GCS component proteins has a direct influence on the rate of glycine synthesis, namely higher ratios of P protein and especially H protein to T and L proteins are favorable, and the carboxylation reaction catalyzed by P protein is a key step determining the glycine synthesis rate, whereas increasing the ratio of L protein to other GCS proteins does not have significant effect and the ratio of T protein to other GCS proteins should be kept low. The effect of substrate concentrations on glycine synthesis is quite complex, showing interdependence with the ratios of GCS component proteins. Furthermore, adding the reducing agent dithiothreitol to the reaction mixture not only results in great tolerance to high concentration of formaldehyde, but also increases the rate of glycine synthesis, probably due to its functions in activating P protein and taking up the role of L protein in the non-enzymatic reduction of H ox to H red . Moreover, the presence of some monovalent and divalent metal ions can have either positive or negative effect on the rate of glycine synthesis, depending on their type and their concentration.
研究领域:
生物化学
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代谢工程
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微生物学
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产品关联
DOI
PubMed
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2023
·
IF 3.4
Fangfang Chang,Yuheng Wang,Jie Zhang,Tao Tu,Huiying Luo,Huoqing Huang,Yingguo Bai,Xing Qin,Yaru Wang,Bin Yao,Yuan Wang,Xiaolu Wang
γ-Aminobutyric acid (GABA) has been widely used in the food, feed, pharmaceutical, and chemical industry fields. Previously, we developed a whole-cell catalyst capable of converting L-glutamate (L-Glu) into GABA by overexpressing the glutamate decarboxylase gene ( gadz11 ) from Bacillus sp. Z11 in Escherichia coli BL21(DE3). However, to enhance cell permeability , a freeze-thaw treatment is required, and to enhance GADZ11 activity, pyridoxal 5′-phosphate (PLP) must be added to the reaction system. The aim of this study is to provide a more efficient approach for GABA production by engineering the recombinant E. coli above. First, the inducible expression conditions of the gadz11 in E. coli were optimized to 37 °C for 6 h. Next, an ideal engineered strain was produced via increasing cell permeability by overexpressing sulA and eliminating PLP dependence by constructing a self-sufficient system. Furthermore, an efficient whole-cell biocatalytic process was optimized. The optimal substrate concentration , cell density, and reaction temperature were 1.0 mol/L (the molecular ratio of L-Glu to L-monosodium glutamate (L-MSG) was 4:1), 15 and 37 °C, respectively. Finally, a whole-cell bioconversion procedure was performed in a 3-L bioreactor under optimal conditions. The strain could be reused for at least two cycles with GABA yield, productivity and conversion ratio of 206.2 g/L, 117.8 g/L/h and 100.0%, respectively. This is currently the highest GABA productivity from a mixture of L-Glu and L-MSG reported without the addition of cofactors or additional treatment of cells. This work demonstrates that the novel engineered E. coli strain has the potential for application in large-scale industrial GABA production.
研究领域:
生物技术
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微生物学
·
生物化工
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代谢工程
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产品关联
DOI
PubMed
高影响因子
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