Engineering a CRISPRi Circuit for Autonomous Control of Metabolic Flux in Escherichia coli

2021 ◽  
Author(s):  
Cong Gao ◽  
Liang Guo ◽  
Guipeng Hu ◽  
Jia Liu ◽  
Xiulai Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux ◽  
Autonomous Control

scholarly journals Optogenetic switch for controlling the central metabolic flux of Escherichia coli

2019 ◽  
Vol 55 ◽  
pp. 68-75 ◽  
Author(s):  
Sebastian Tommi Tandar ◽  
Sachie Senoo ◽  
Yoshihiro Toya ◽  
Hiroshi Shimizu
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux

scholarly journals Metabolic Characterization of Escherichia coli Strains Adapted to Growth on Lactate

2007 ◽  
Vol 73 (14) ◽  
pp. 4639-4647 ◽  
Author(s):  
Qiang Hua ◽  
Andrew R. Joyce ◽  
Bernhard Ø. Palsson ◽  
Stephen S. Fong
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux ◽  
Carbon Sources ◽  
Carbon Substrate ◽  
Flux Analysis ◽  
Average Growth ◽  
Laboratory Evolution ◽  
Average Biomass ◽  
Evolutionary Trajectories ◽  
Genetic Mechanisms

ABSTRACT In comparison with intensive studies of genetic mechanisms related to biological evolutionary systems, much less analysis has been conducted on metabolic network responses to adaptive evolution that are directly associated with evolved metabolic phenotypes. Metabolic mechanisms involved in laboratory evolution of Escherichia coli on gluconeogenic carbon sources, such as lactate, were studied based on intracellular flux states determined from 13C tracer experiments and 13C-constrained flux analysis. At the end point of laboratory evolution, strains exhibited a more than doubling of the average growth rate and a 50% increase in the average biomass yield. Despite different evolutionary trajectories among parallel evolved populations, most improvements were obtained within the first 250 generations of evolution and were generally characterized by a significant increase in pathway capacity. Partitioning between gluconeogenic and pyruvate catabolic flux at the pyruvate node remained almost unchanged, while flux distributions around the key metabolites phosphoenolpyruvate, oxaloacetate, and acetyl-coenzyme A were relatively flexible over the course of evolution on lactate to meet energetic and anabolic demands during rapid growth on this gluconeogenic carbon substrate. There were no clear qualitative correlations between most transcriptional expression and metabolic flux changes, suggesting complex regulatory mechanisms at multiple levels of genetics and molecular biology. Moreover, higher fitness gains for cell growth on both evolutionary and alternative carbon sources were found for strains that adaptively evolved on gluconeogenic carbon sources compared to those that evolved on glucose. These results provide a novel systematic view of the mechanisms underlying microbial adaptation to growth on a gluconeogenic substrate.

scholarly journals Rewiring of glycerol metabolism in Escherichia coli for effective production of recombinant proteins

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Chung-Jen Chiang ◽  
Yi-Jing Ho ◽  
Mu-Chen Hu ◽  
Yun-Peng Chao
Keyword(s):  
Escherichia Coli ◽  
Crude Glycerol ◽  
Metabolic Flux ◽  
Raw Materials ◽  
Tricarboxylic Acid Cycle ◽  
Cost Effective ◽  
Fold Increase ◽  
Pentose Phosphate ◽  
Glycerol Metabolism ◽  
Related Field

Abstract Background The economic viability of a protein-production process relies highly on the production titer and the price of raw materials. Crude glycerol coming from the production of biodiesel is a renewable and cost-effective resource. However, glycerol is inefficiently utilized by Escherichia coli. Results This issue was addressed by rewiring glycerol metabolism for redistribution of the metabolic flux. Key steps in central metabolism involving the glycerol dissimilation pathway, the pentose phosphate pathway, and the tricarboxylic acid cycle were pinpointed and manipulated to provide precursor metabolites and energy. As a result, the engineered E. coli strain displayed a 9- and 30-fold increase in utilization of crude glycerol and production of the target protein, respectively. Conclusions The result indicates that the present method of metabolic engineering is useful and straightforward for efficient adjustment of the flux distribution in glycerol metabolism. The practical application of this methodology in biorefinery and the related field would be acknowledged.

scholarly journals Metabolic Flux Control at the Pyruvate Node in an Anaerobic Escherichia coli Strain with an Active Pyruvate Dehydrogenase

2010 ◽  
Vol 76 (7) ◽  
pp. 2107-2114 ◽  
Author(s):  
Qingzhao Wang ◽  
Mark S. Ou ◽  
Y. Kim ◽  
L. O. Ingram ◽  
K. T. Shanmugam
Keyword(s):  
Escherichia Coli ◽  
Mutant Strain ◽  
Pyruvate Dehydrogenase ◽  
Metabolic Flux ◽  
Anaerobic Growth ◽  
Kinetic Properties ◽  
Fermentation Products ◽  
E Coli ◽  
Pyruvate Node

ABSTRACT During anaerobic growth of Escherichia coli, pyruvate formate-lyase (PFL) and lactate dehydrogenase (LDH) channel pyruvate toward a mixture of fermentation products. We have introduced a third branch at the pyruvate node in a mutant of E. coli with a mutation in pyruvate dehydrogenase (PDH*) that renders the enzyme less sensitive to inhibition by NADH. The key starting enzymes of the three branches at the pyruvate node in such a mutant, PDH*, PFL, and LDH, have different metabolic potentials and kinetic properties. In such a mutant (strain QZ2), pyruvate flux through LDH was about 30%, with the remainder of the flux occurring through PFL, indicating that LDH is a preferred route of pyruvate conversion over PDH*. In a pfl mutant (strain YK167) with both PDH* and LDH activities, flux through PDH* was about 33% of the total, confirming the ability of LDH to outcompete the PDH pathway for pyruvate in vivo. Only in the absence of LDH (strain QZ3) was pyruvate carbon equally distributed between the PDH* and PFL pathways. A pfl mutant with LDH and PDH* activities, as well as a pfl ldh double mutant with PDH* activity, had a surprisingly low cell yield per mole of ATP (Y ATP) (about 7.0 g of cells per mol of ATP) compared to 10.9 g of cells per mol of ATP for the wild type. The lower Y ATP suggests the operation of a futile energy cycle in the absence of PFL in this strain. An understanding of the controls at the pyruvate node during anaerobic growth is expected to provide unique insights into rational metabolic engineering of E. coli and related bacteria for the production of various biobased products at high rates and yields.

scholarly journals Investigation of useful carbon tracers for 13 C-metabolic flux analysis of Escherichia coli by considering five experimentally determined flux distributions

2016 ◽  
Vol 3 ◽  
pp. 187-195 ◽  
Author(s):  
Kousuke Maeda ◽  
Nobuyuki Okahashi ◽  
Yoshihiro Toya ◽  
Fumio Matsuda ◽  
Hiroshi Shimizu
Keyword(s):  
Escherichia Coli ◽  
Metabolic Flux Analysis ◽  
Metabolic Flux ◽  
Flux Analysis
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