Metabolic flux redistribution in Corynebacterium glutamicum in response to osmotic stress

2003 ◽  
Vol 60 (5) ◽  
pp. 547-555 ◽  
Author(s):  
C. Varela ◽  
E. Agosin ◽  
M. Baez ◽  
M. Klapa ◽  
G. Stephanopoulos
Keyword(s):  
Osmotic Stress ◽  
Corynebacterium Glutamicum ◽  
Metabolic Flux ◽  
Flux Redistribution

scholarly journals Osmotic Stress Response: Quantification of Cell Maintenance and Metabolic Fluxes in a Lysine-Overproducing Strain of Corynebacterium glutamicum

2004 ◽  
Vol 70 (7) ◽  
pp. 4222-4229 ◽  
Author(s):  
Cristian A. Varela ◽  
Mauricio E. Baez ◽  
Eduardo Agosin
Keyword(s):  
Osmotic Stress ◽  
Corynebacterium Glutamicum ◽  
Metabolic Flux ◽  
Cell Metabolism ◽  
Compatible Solutes ◽  
Flux Analysis ◽  
High Dilution ◽  
Metabolic Fluxes ◽  
Cell Productivity ◽  
Osmotic Stress Response

ABSTRACT Osmotic stress diminishes cell productivity and may cause cell inactivation in industrial fermentations. The quantification of metabolic changes under such conditions is fundamental for understanding and describing microbial behavior during bioprocesses. We quantified the gradual changes that take place when a lysine-overproducing strain of Corynebacterium glutamicum is grown in continuous culture with saline gradients at different dilution rates. The use of compatible solutes depended on environmental conditions; certain osmolites predominated at different dilution rates and extracellular osmolalities. A metabolic flux analysis showed that at high dilution rates C. glutamicum redistributed its metabolic fluxes, favoring energy formation over growth. At low dilution rates, cell metabolism accelerated as the osmolality was steadily increased. Flexibility in the oxaloacetate node proved to be key for the energetic redistribution that occurred when cells were grown at high dilution rates. Substrate and ATP maintenance coefficients increased 30- and 5-fold, respectively, when the osmolality increased, which demonstrates that energy pool management is fundamental for sustaining viability.

scholarly journals Metabolic Fluxes in Corynebacterium glutamicum during Lysine Production with Sucrose as Carbon Source

2004 ◽  
Vol 70 (12) ◽  
pp. 7277-7287 ◽  
Author(s):  
Christoph Wittmann ◽  
Patrick Kiefer ◽  
Oskar Zelder
Keyword(s):  
Carbon Source ◽  
Corynebacterium Glutamicum ◽  
Metabolic Flux ◽  
Tca Cycle ◽  
Pentose Phosphate ◽  
Flux Analysis ◽  
Phosphotransferase System ◽  
Lysine Production ◽  
Metabolic Fluxes ◽  
Fructose 1,6 Bisphosphate

ABSTRACT Metabolic fluxes in the central metabolism were determined for lysine-producing Corynebacterium glutamicum ATCC 21526 with sucrose as a carbon source, providing an insight into molasses-based industrial production processes with this organism. For this purpose, 13C metabolic flux analysis with parallel studies on [1-13CFru]sucrose, [1-13CGlc]sucrose, and [13C6 Fru]sucrose was carried out. C. glutamicum directed 27.4% of sucrose toward extracellular lysine. The strain exhibited a relatively high flux of 55.7% (normalized to an uptake flux of hexose units of 100%) through the pentose phosphate pathway (PPP). The glucose monomer of sucrose was completely channeled into the PPP. After transient efflux, the fructose residue was mainly taken up by the fructose-specific phosphotransferase system (PTS) and entered glycolysis at the level of fructose-1,6-bisphosphate. Glucose-6-phosphate isomerase operated in the gluconeogenetic direction from fructose-6-phosphate to glucose-6-phosphate and supplied additional carbon (7.2%) from the fructose part of the substrate toward the PPP. This involved supply of fructose-6-phosphate from the fructose part of sucrose either by PTSMan or by fructose-1,6-bisphosphatase. C. glutamicum further exhibited a high tricarboxylic acid (TCA) cycle flux of 78.2%. Isocitrate dehydrogenase therefore significantly contributed to the total NADPH supply of 190%. The demands for lysine (110%) and anabolism (32%) were lower than the supply, resulting in an apparent NADPH excess. The high TCA cycle flux and the significant secretion of dihydroxyacetone and glycerol display interesting targets to be approached by genetic engineers for optimization of the strain investigated.

Pathway identification combining metabolic flux and functional genomics analyses: Acetate and propionate activation by Corynebacterium glutamicum

2009 ◽  
Vol 140 (1-2) ◽  
pp. 75-83 ◽  
Author(s):  
Andrea Veit ◽  
Doris Rittmann ◽  
Tobias Georgi ◽  
Jung-Won Youn ◽  
Bernhard J. Eikmanns ◽  
...  
Keyword(s):  
Functional Genomics ◽  
Corynebacterium Glutamicum ◽  
Metabolic Flux

Impacts of Sodium Citrate on Metabolic Flux Distributions of L-Valine Fermentation

2011 ◽  
Vol 343-344 ◽  
pp. 643-648
Author(s):  
Qing Yang Xu ◽  
Lei Ma ◽  
Xi Xian Xie ◽  
Ning Chen ◽  
Jian Wang
Keyword(s):  
Corynebacterium Glutamicum ◽  
Culture Medium ◽  
Metabolic Flux ◽  
Sodium Citrate ◽  
Flux Distribution ◽  
Metabolic Flux Distribution ◽  
Key Nodes

The effect of sodium citrate on the metabolic flux distributions in the middle and late periods of L-valine production by Corynebacterium glutamicum XV0505 was obtained. It was shown that when sodium citrate (2.0 g/L) was added into the initial fermentation culture medium, the metabolic flux of Embden-Meyerhof-Parnas (EMP) route decreased from 96.43 to 91.13, and the metabolic flux of Hexose Monophophate (HMP) route increased from 3.56 to 8.87, and the metabolic flux flowing to L-alanine and acetate was decreased by 21.1% and 32.4%, respectively. Meanwhile, the metabolic flux of biosynthesis route of L-valine was increased by 10.74%. Therefore, sodium citrate can change the metabolic flux distribution in the key nodes of biosynthesis route of L-valine, decrease the generation of byproducts, and increase the metabolic flux in the biosynthesis route of L-valine.

scholarly journals Enhancing glutamine production by optimising the GS-GOGAT pathway in Corynebacterium glutamicum and NH4+-limited fermentation

2021 ◽  
Author(s):  
Yunpeng Liu ◽  
Lanxiao Li ◽  
Jinduo Wang ◽  
Qingyang Xu
Keyword(s):  
Bacillus Subtilis ◽  
Corynebacterium Glutamicum ◽  
Lactobacillus Acidophilus ◽  
Fermentation Process ◽  
Metabolic Flux ◽  
Feeding Strategies ◽  
Original Strain ◽  
Strong Promoter ◽  
Glutamine Synthase ◽  
Glutamine Production

Abstract: The GS-GOGAT pathway is a key metabolic pathway of glutamate and glutamine. Optimising this pathway, leading to metabolic flux to glutamine, can increase glutamine production and reduce the production of the by-product glutamate. The NH-limited fermentation process limits the concentration of NH to increase the activity of GS and further increase the yield of glutamine. The GS-GOGAT pathway was optimised by knocking out the GOGAT genes NCgl0181 and NCgl0182 and the glutaminase genes NCgl2395 and NCgl2500 and by integrating a copy of the GS gene glnAbsu from Bacillus subtilis and a copy of the glutamine synthase gene glnAlcb from Lactobacillus acidophilus into the genomic NCgl0182 and NCgl2500 sites. Furthermore, the pXT01 plasmid with the strong promoter tuf was used to overexpress glnAbsu and glnAlcb. To obtain an optimal NH-limited fermentation process, the effects of starting feeding with (NH)SO at different times of fermentation and three (NH)SO feeding strategies on glutamine fermentation were studied, and a NH-limited fermentation process that was the most suitable for glutamine fermentation was determined. After optimising the GS-GOGAT pathway, Corynebacterium glutamicum G-6 was subjected to the NH-limited fermentation process to greatly increase the production of glutamine. The yield of glutamine reached 98.7 g/L, which was 104.8% higher than that in the original strain GM34; the content of glutamate reached 4.5 g/L, which then decreased by 85.2%; the GS activity increased significantly, and the sugar-acid conversion rate reached 41.2%.

scholarly journals Enhancing glutamine production by optimising the GS-GOGAT pathway in Corynebacterium glutamicum and NH4+-limited fermentation

2021 ◽  
Author(s):  
Yunpeng Liu ◽  
Lanxiao Li ◽  
Jinduo Wang ◽  
Qingyang Xu
Keyword(s):  
Bacillus Subtilis ◽  
Corynebacterium Glutamicum ◽  
Lactobacillus Acidophilus ◽  
Fermentation Process ◽  
Metabolic Flux ◽  
Feeding Strategies ◽  
Original Strain ◽  
Strong Promoter ◽  
Glutamine Synthase ◽  
Glutamine Production

Abstract: The GS-GOGAT pathway is a key metabolic pathway of glutamate and glutamine. Optimising this pathway, leading to metabolic flux to glutamine, can increase glutamine production and reduce the production of the by-product glutamate. The NH-limited fermentation process limits the concentration of NH to increase the activity of GS and further increase the yield of glutamine. The GS-GOGAT pathway was optimised by knocking out the GOGAT genes NCgl0181 and NCgl0182 and the glutaminase genes NCgl2395 and NCgl2500 and by integrating a copy of the GS gene glnAbsu from Bacillus subtilis and a copy of the glutamine synthase gene glnAlcb from Lactobacillus acidophilus into the genomic NCgl0182 and NCgl2500 sites. Furthermore, the pXT01 plasmid with the strong promoter tuf was used to overexpress glnAbsu and glnAlcb. To obtain an optimal NH-limited fermentation process, the effects of starting feeding with (NH)SO at different times of fermentation and three (NH)SO feeding strategies on glutamine fermentation were studied, and a NH-limited fermentation process that was the most suitable for glutamine fermentation was determined. After optimising the GS-GOGAT pathway, Corynebacterium glutamicum G-6 was subjected to the NH-limited fermentation process to greatly increase the production of glutamine. The yield of glutamine reached 98.7 g/L, which was 104.8% higher than that in the original strain GM34; the content of glutamate reached 4.5 g/L, which then decreased by 85.2%; the GS activity increased significantly, and the sugar-acid conversion rate reached 41.2%.

Enhanced Production of 5-aminolevulinic Acid via Flux Redistribution of TCA Cycle toward l-Glutamate in Corynebacterium glutamicum

2019 ◽  
Vol 24 (6) ◽  
pp. 915-923 ◽  
Author(s):  
Young Jin Ko ◽  
Seung Kyou You ◽  
Minhye Kim ◽  
Eunhye Lee ◽  
Sang Kyu Shin ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Aminolevulinic Acid ◽  
Tca Cycle ◽  
Enhanced Production ◽  
Flux Redistribution
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