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Thomas Walther - One of the best experts on this subject based on the ideXlab platform.
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engineering of escherichia coli for krebs cycle dependent production of malic acid
Microbial Cell Factories, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Marc Carnicerheras, Stephanie Heux, Jean Marie Francois, Thomas WaltherAbstract:Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coli for Krebs cycle-dependent production of malic acid that can satisfy these requirements. We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using 13C-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Δmdh Δmqo ΔmaeAB ΔiclR ΔarcA which expressed Malate-insensitive PEP carboxylase PpcK620S and NADH-insensitive citrate synthase GltAR164L. We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malate-derived metabolites such as 2,4-dihydroxybutyric acid.
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Engineering of Escherichia coli for Krebs cycle-dependent production of malic acid
BMC, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Stephanie Heux, Jean Marie Francois, Marc Carnicer-heras, Thomas WaltherAbstract:Abstract Background Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coli for Krebs cycle-dependent production of malic acid that can satisfy these requirements. Results We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using 13C-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Δmdh Δmqo ΔmaeAB ΔiclR ΔarcA which expressed Malate-insensitive PEP carboxylase PpcK620S and NADH-insensitive citrate synthase GltAR164L. We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Conclusions Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malate-derived metabolites such as 2,4-dihydroxybutyric acid
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Engineering of Escherichia coli for Krebs cycle-dependent production of malic acid
Microbial Cell Factories, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Stephanie Heux, Jean Marie Francois, Marc Carnicer-heras, Thomas WaltherAbstract:Background: Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coil for Krebs cycle-dependent production of malic acid that can satisfy these requirements. Results: We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using C-13-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Delta mdh Delta mqo Delta maeAB Delta iclR Delta arcA which expressed Malate-insensitive PEP carboxylase Ppc(K6)(205) and NADH-insensitive citrate synthase GltA(R1641) . We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Conclusions: Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malatederived metabolites such as 2,4-dihydroxybutyric acid.
Guoliang Ji - One of the best experts on this subject based on the ideXlab platform.
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effect of low molecular weight organic anions on electrokinetic properties of variable charge soils
Journal of Colloid and Interface Science, 2004Co-Authors: Ren-kou Xu, Chengbao Li, Guoliang JiAbstract:Abstract It is known that some inorganic anions can be adsorbed by variable-charge soils specifically, resulting in the lowering of the ζ potential of the clay particle. Reasoning similarly, organic anions should also have such an effect. In this article, the effect of the anions of five low-molecular-weight (LMW) organic acids existing widely in soils on the ζ potentials of two variable-charge soils was examined. The results showed that the presence of organic anions led to a decrease in ζ potential. The effect of different anions on ζ potential followed the order oxalate>citrate>Malate>maleate>acetate. The effect increased with the increase in anion concentration and decreased with the increase in pH. The extent of the effect on different soils was apparently related to their iron oxide content. The presence of organic anions also led to a decrease in the isoelectric point (IEP) of the soil. The IEPs of two soils in organic anion systems followed the order acetate>maleate>Malate>citrate. No IEP was detected for the oxalate system.
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effect of low molecular weight organic anions on electrokinetic properties of variable charge soils
Journal of Colloid and Interface Science, 2004Co-Authors: Ren-kou Xu, Chengbao Li, Guoliang JiAbstract:Abstract It is known that some inorganic anions can be adsorbed by variable-charge soils specifically, resulting in the lowering of the ζ potential of the clay particle. Reasoning similarly, organic anions should also have such an effect. In this article, the effect of the anions of five low-molecular-weight (LMW) organic acids existing widely in soils on the ζ potentials of two variable-charge soils was examined. The results showed that the presence of organic anions led to a decrease in ζ potential. The effect of different anions on ζ potential followed the order oxalate>citrate>Malate>maleate>acetate. The effect increased with the increase in anion concentration and decreased with the increase in pH. The extent of the effect on different soils was apparently related to their iron oxide content. The presence of organic anions also led to a decrease in the isoelectric point (IEP) of the soil. The IEPs of two soils in organic anion systems followed the order acetate>maleate>Malate>citrate. No IEP was detected for the oxalate system.
Bangpeng Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of organic chemicals on growth of methylosinus trichosporium ob3b
Biochemical Engineering Journal, 2006Co-Authors: Xinhui Xing, Hao Wu, Bangpeng WangAbstract:Effects of organic chemicals on the growth rate and cell density of Methylosinus trichosporium OB3b, a type II methanotroph, were studied. The examined organic chemicals were vitamins, amino acids and organic acids, including folic acid, riboflavin, tetrahydrofuran, cysteine, tyrosine, glycine, pyruvic acid, Malate, maleic acid, and citrate. The results showed that M. trichosporium OB3b could not utilize the added organics as the sole carbon source for cell growth without the presence of methane. Riboflavin and organic acids such as Malate, citrate, succinate and maleate could obviously improve the cell concentration of this strain. Among them, citrate exhibited the most significant effect on cell growth enhancement. When citrate was added at an optimal concentration of 0.015 mmol/L, the maximal cell concentration could reach 0.75 g dry cell weight/L, about 3.5 times that of the control without citrate addition. Furthermore, the improvement of the cell growth of M. trichosporium OB3b by the addition of citrate was confirmed in a bioreactor with a continuous supply of air and methane.
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effects of organic chemicals on growth of methylosinus trichosporium ob3b
Biochemical Engineering Journal, 2006Co-Authors: Xinhui Xing, Hao Wu, Bangpeng WangAbstract:Effects of organic chemicals on the growth rate and cell density of Methylosinus trichosporium OB3b, a type II methanotroph, were studied. The examined organic chemicals were vitamins, amino acids and organic acids, including folic acid, riboflavin, tetrahydrofuran, cysteine, tyrosine, glycine, pyruvic acid, Malate, maleic acid, and citrate. The results showed that M. trichosporium OB3b could not utilize the added organics as the sole carbon source for cell growth without the presence of methane. Riboflavin and organic acids such as Malate, citrate, succinate and maleate could obviously improve the cell concentration of this strain. Among them, citrate exhibited the most significant effect on cell growth enhancement. When citrate was added at an optimal concentration of 0.015 mmol/L, the maximal cell concentration could reach 0.75 g dry cell weight/L, about 3.5 times that of the control without citrate addition. Furthermore, the improvement of the cell growth of M. trichosporium OB3b by the addition of citrate was confirmed in a bioreactor with a continuous supply of air and methane.
Ren-kou Xu - One of the best experts on this subject based on the ideXlab platform.
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effect of low molecular weight organic anions on electrokinetic properties of variable charge soils
Journal of Colloid and Interface Science, 2004Co-Authors: Ren-kou Xu, Chengbao Li, Guoliang JiAbstract:Abstract It is known that some inorganic anions can be adsorbed by variable-charge soils specifically, resulting in the lowering of the ζ potential of the clay particle. Reasoning similarly, organic anions should also have such an effect. In this article, the effect of the anions of five low-molecular-weight (LMW) organic acids existing widely in soils on the ζ potentials of two variable-charge soils was examined. The results showed that the presence of organic anions led to a decrease in ζ potential. The effect of different anions on ζ potential followed the order oxalate>citrate>Malate>maleate>acetate. The effect increased with the increase in anion concentration and decreased with the increase in pH. The extent of the effect on different soils was apparently related to their iron oxide content. The presence of organic anions also led to a decrease in the isoelectric point (IEP) of the soil. The IEPs of two soils in organic anion systems followed the order acetate>maleate>Malate>citrate. No IEP was detected for the oxalate system.
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effect of low molecular weight organic anions on electrokinetic properties of variable charge soils
Journal of Colloid and Interface Science, 2004Co-Authors: Ren-kou Xu, Chengbao Li, Guoliang JiAbstract:Abstract It is known that some inorganic anions can be adsorbed by variable-charge soils specifically, resulting in the lowering of the ζ potential of the clay particle. Reasoning similarly, organic anions should also have such an effect. In this article, the effect of the anions of five low-molecular-weight (LMW) organic acids existing widely in soils on the ζ potentials of two variable-charge soils was examined. The results showed that the presence of organic anions led to a decrease in ζ potential. The effect of different anions on ζ potential followed the order oxalate>citrate>Malate>maleate>acetate. The effect increased with the increase in anion concentration and decreased with the increase in pH. The extent of the effect on different soils was apparently related to their iron oxide content. The presence of organic anions also led to a decrease in the isoelectric point (IEP) of the soil. The IEPs of two soils in organic anion systems followed the order acetate>maleate>Malate>citrate. No IEP was detected for the oxalate system.
Debora Trichez - One of the best experts on this subject based on the ideXlab platform.
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engineering of escherichia coli for krebs cycle dependent production of malic acid
Microbial Cell Factories, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Marc Carnicerheras, Stephanie Heux, Jean Marie Francois, Thomas WaltherAbstract:Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coli for Krebs cycle-dependent production of malic acid that can satisfy these requirements. We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using 13C-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Δmdh Δmqo ΔmaeAB ΔiclR ΔarcA which expressed Malate-insensitive PEP carboxylase PpcK620S and NADH-insensitive citrate synthase GltAR164L. We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malate-derived metabolites such as 2,4-dihydroxybutyric acid.
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Engineering of Escherichia coli for Krebs cycle-dependent production of malic acid
BMC, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Stephanie Heux, Jean Marie Francois, Marc Carnicer-heras, Thomas WaltherAbstract:Abstract Background Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coli for Krebs cycle-dependent production of malic acid that can satisfy these requirements. Results We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using 13C-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Δmdh Δmqo ΔmaeAB ΔiclR ΔarcA which expressed Malate-insensitive PEP carboxylase PpcK620S and NADH-insensitive citrate synthase GltAR164L. We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Conclusions Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malate-derived metabolites such as 2,4-dihydroxybutyric acid
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Engineering of Escherichia coli for Krebs cycle-dependent production of malic acid
Microbial Cell Factories, 2018Co-Authors: Debora Trichez, Clement Auriol, Audrey Baylac, Romain Irague, Clementine Dressaire, Stephanie Heux, Jean Marie Francois, Marc Carnicer-heras, Thomas WaltherAbstract:Background: Malate is a C4-dicarboxylic acid widely used as an acidulant in the food and beverage industry. Rational engineering has been performed in the past for the development of microbial strains capable of efficient production of this metabolite. However, as Malate can be a precursor for specialty chemicals, such as 2,4-dihydroxybutyric acid, that require additional cofactors NADP(H) and ATP, we set out to reengineer Escherichia coil for Krebs cycle-dependent production of malic acid that can satisfy these requirements. Results: We found that significant Malate production required at least simultaneous deletion of all malic enzymes and dehydrogenases, and concomitant expression of a Malate-insensitive PEP carboxylase. Metabolic flux analysis using C-13-labeled glucose indicated that Malate-producing strains had a very high flux over the glyoxylate shunt with almost no flux passing through the isocitrate dehydrogenase reaction. The highest Malate yield of 0.82 mol/mol was obtained with E. coli Delta mdh Delta mqo Delta maeAB Delta iclR Delta arcA which expressed Malate-insensitive PEP carboxylase Ppc(K6)(205) and NADH-insensitive citrate synthase GltA(R1641) . We also showed that inactivation of the dicarboxylic acid transporter DcuA strongly reduced Malate production arguing for a pivotal role of this permease in Malate export. Conclusions: Since more NAD(P)H and ATP cofactors are generated in the Krebs cycle-dependent Malate production when compared to pathways which depend on the function of anaplerotic PEP carboxylase or PEP carboxykinase enzymes, the engineered strain developed in this study can serve as a platform to increase biosynthesis of Malatederived metabolites such as 2,4-dihydroxybutyric acid.
