scholarly journals Coordination of FocA and Pyruvate Formate-Lyase Synthesis in Escherichia coli Demonstrates Preferential Translocation of Formate over Other Mixed-Acid Fermentation Products

2013 ◽  
Vol 195 (7) ◽  
pp. 1428-1435 ◽  
Author(s):  
L. Beyer ◽  
C. Doberenz ◽  
D. Falke ◽  
D. Hunger ◽  
B. Suppmann ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acid Fermentation ◽  
Pyruvate Formate Lyase ◽  
Fermentation Products ◽  
Mixed Acid Fermentation ◽  
Mixed Acid

scholarly journals Aerobic Fermentation of d-Glucose by an Evolved Cytochrome Oxidase-Deficient Escherichia coli Strain

2008 ◽  
Vol 74 (24) ◽  
pp. 7561-7569 ◽  
Author(s):  
Vasiliy A. Portnoy ◽  
Markus J. Herrgård ◽  
Bernhard Ø. Palsson
Keyword(s):  
Escherichia Coli ◽  
Oxygen Uptake ◽  
Growth Conditions ◽  
Aerobic Growth ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
E Coli ◽  
Knockout Strain ◽  
Mixed Acid ◽  
Cytochrome Oxidases

ABSTRACT Fermentation of glucose to d-lactic acid under aerobic growth conditions by an evolved Escherichia coli mutant deficient in three terminal oxidases is reported in this work. Cytochrome oxidases (cydAB, cyoABCD, and cbdAB) were removed from the E. coli K12 MG1655 genome, resulting in the ECOM3 (E. coli cytochrome oxidase mutant) strain. Removal of cytochrome oxidases reduced the oxygen uptake rate of the knockout strain by nearly 85%. Moreover, the knockout strain was initially incapable of growing on M9 minimal medium. After the ECOM3 strain was subjected to adaptive evolution on glucose M9 medium for 60 days, a growth rate equivalent to that of anaerobic wild-type E. coli was achieved. Our findings demonstrate that three independently adaptively evolved ECOM3 populations acquired different phenotypes: one produced lactate as a sole fermentation product, while the other two strains exhibited a mixed-acid fermentation under oxic growth conditions with lactate remaining as the major product. The homofermenting strain showed a d-lactate yield of 0.8 g/g from glucose. Gene expression and in silico model-based analyses were employed to identify perturbed pathways and explain phenotypic behavior. Significant upregulation of ygiN and sodAB explains the remaining oxygen uptake that was observed in evolved ECOM3 strains. E. coli strains produced in this study showed the ability to produce lactate as a fermentation product from glucose and to undergo mixed-acid fermentation during aerobic growth.

Engineering Escherichia coli with acrylate pathway genes for propionic acid synthesis and its impact on mixed-acid fermentation

2012 ◽  
Vol 97 (3) ◽  
pp. 1191-1200 ◽  
Author(s):  
Vijayalakshmi Kandasamy ◽  
Hema Vaidyanathan ◽  
Ivana Djurdjevic ◽  
Elamparithi Jayamani ◽  
K. B. Ramachandran ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Propionic Acid ◽  
Acid Synthesis ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
Mixed Acid ◽  
Acrylate Pathway

scholarly journals Pyruvate Formate Lyase Is Required for Pneumococcal Fermentative Metabolism and Virulence

2009 ◽  
Vol 77 (12) ◽  
pp. 5418-5427 ◽  
Author(s):  
Hasan Yesilkaya ◽  
Francesca Spissu ◽  
Sandra M. Carvalho ◽  
Vanessa S. Terra ◽  
Karen A. Homer ◽  
...  
Keyword(s):  
Wild Type ◽  
Product Analysis ◽  
Acid Fermentation ◽  
Pyruvate Formate Lyase ◽  
Growth And Survival ◽  
Mixed Acid Fermentation ◽  
Mixed Acid ◽  
Fermentative Metabolism ◽  
In The Wild

ABSTRACT Knowledge of the in vivo physiology and metabolism of Streptococcus pneumoniae is limited, even though pneumococci rely on efficient acquisition and metabolism of the host nutrients for growth and survival. Because the nutrient-limited, hypoxic host tissues favor mixed-acid fermentation, we studied the role of the pneumococcal pyruvate formate lyase (PFL), a key enzyme in mixed-acid fermentation, which is activated posttranslationally by PFL-activating enzyme (PFL-AE). Mutations were introduced to two putative pfl genes, SPD0235 and SPD0420, and two putative pfl A genes, SPD0229 and SPD1774. End-product analysis showed that there was no formate, the main end product of the reaction catalyzed by PFL, produced by mutants defective in SPD0420 and SPD1774, indicating that SPD0420 codes for PFL and SPD1774 for putative PFL-AE. Expression of SPD0420 was elevated in galactose-containing medium in anaerobiosis compared to growth in glucose, and the mutation of SPD0420 resulted in the upregulation of fba and pyk, encoding, respectively, fructose 1,6-bisphosphate aldolase and pyruvate kinase, under the same conditions. In addition, an altered fatty acid composition was detected in SPD0420 and SPD1774 mutants. Mice infected intranasally with the SPD0420 and SPD1774 mutants survived significantly longer than the wild type-infected cohort, and bacteremia developed later in the mutant cohort than in the wild type-infected group. Furthermore, the numbers of CFU of the SPD0420 mutant were lower in the nasopharynx and the lungs after intranasal infection, and fewer numbers of mutant CFU than of wild-type CFU were recovered from blood specimens after intravenous infection. The results demonstrate that there is a direct link between pneumococcal fermentative metabolism and virulence.

scholarly journals Metabolic engineering of the mixed-acid fermentation pathway of Escherichia coli for anaerobic production of glutamate and itaconate

AMB Express ◽  
2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Kiira S. Vuoristo ◽  
Astrid E. Mars ◽  
Jose Vidal Sangra ◽  
Jan Springer ◽  
Gerrit Eggink ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Metabolic Engineering ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
Mixed Acid ◽  
Anaerobic Production

Production of polyhydroxyalkanoates by Escherichia coli mutants with defected mixed acid fermentation pathways

2010 ◽  
Vol 87 (6) ◽  
pp. 2247-2256 ◽  
Author(s):  
Jia Jian ◽  
Shao-Qin Zhang ◽  
Zhen-Yu Shi ◽  
Wei Wang ◽  
Guo-Qiang Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
Mixed Acid

scholarly journals On-line analysis and in situ pH monitoring of mixed acid fermentation by Escherichia coli using combined FTIR and Raman techniques

2020 ◽  
Vol 412 (26) ◽  
pp. 7307-7319
Author(s):  
George D. Metcalfe ◽  
Thomas W. Smith ◽  
Michael Hippler
Keyword(s):  
Escherichia Coli ◽  
Detection Limits ◽  
Bacterial Suspension ◽  
Spectral Features ◽  
Order Kinetic ◽  
Acid Fermentation ◽  
Mixed Acid Fermentation ◽  
Mixed Acid ◽  
Formate Decomposition

Abstract We introduce an experimental setup allowing continuous monitoring of bacterial fermentation processes by simultaneous optical density (OD) measurements, long-path FTIR headspace monitoring of CO2, acetaldehyde and ethanol, and liquid Raman spectroscopy of acetate, formate, and phosphate anions, without sampling. We discuss which spectral features are best suited for detection, and how to obtain partial pressures and concentrations by integrations and least squares fitting of spectral features. Noise equivalent detection limits are about 2.6 mM for acetate and 3.6 mM for formate at 5 min integration time, improving to 0.75 mM for acetate and 1.0 mM for formate at 1 h integration. The analytical range extends to at least 1 M with a standard deviation of percentage error of about 8%. The measurement of the anions of the phosphate buffer allows the spectroscopic, in situ determination of the pH of the bacterial suspension via a modified Henderson-Hasselbalch equation in the 6–8 pH range with an accuracy better than 0.1. The 4 m White cell FTIR measurements provide noise equivalent detection limits of 0.21 μbar for acetaldehyde and 0.26 μbar for ethanol in the gas phase, corresponding to 3.2 μM acetaldehyde and 22 μM ethanol in solution, using Henry’s law. The analytical dynamic range exceeds 1 mbar ethanol corresponding to 85 mM in solution. As an application example, the mixed acid fermentation of Escherichia coli is studied. The production of CO2, ethanol, acetaldehyde, acids such as formate and acetate, and the changes in pH are discussed in the context of the mixed acid fermentation pathways. Formate decomposition into CO2 and H2 is found to be governed by a zeroth-order kinetic rate law, showing that adding exogenous formate to a bioreactor with E. coli is expected to have no beneficial effect on the rate of formate decomposition and biohydrogen production.

scholarly journals Metabolic Engineering ofEscherichia colifor Poly(3-hydroxybutyrate) Production under Microaerobic Condition

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xiao-Xing Wei ◽  
Wei-Tao Zheng ◽  
Xue Hou ◽  
Jian Liang ◽  
Zheng-Jun Li
Keyword(s):  
Escherichia Coli ◽  
Carbon Metabolism ◽  
Batch Fermentation ◽  
Dry Weight ◽  
Microaerobic Condition ◽  
Acid Fermentation ◽  
Pyruvate Formate Lyase ◽  
E Coli ◽  
Mixed Acid ◽  
Theoretical Yield

The alcohol dehydrogenase promoterPadhEand mixed acid fermentation pathway deficient mutants ofEscherichia coliwere employed to produce poly(3-hydroxybutyrate) (P3HB) under microaerobic condition. TheE. colimutant withackA-pta, poxB, ldhA, andadhEdeletions accumulated 0.67 g/L P3HB, up to 78.84% of cell dry weight in tube cultivation. The deletion of pyruvate formate-lyase genepflBdrastically decreased P3HB production and P3HB content to 0.09 g/L and 24.44%, respectively. OverexpressingpflBvia the plasmid in its knocked out mutant restored cell growth and P3HB accumulation, indicating the importance of the pyruvate formate-lyase in microaerobic carbon metabolism. The engineeredE. coliBWapld (pWYC09) produced 5.00 g/L P3HB from 16.50 g/L glucose in 24 h batch fermentation, and P3HB production yield from glucose was 0.30 g/g, which reached up to 63% of maximal theoretical yield.

Sign in / Sign up

Export Citation Format

Share Document