Metabolic regulation analysis of an ethanologenic Escherichia coli strain based on RT-PCR and enzymatic activities
Open Access
- 1 May 2008
- journal article
- Published by Springer Nature in Biotechnology for Biofuels
- Vol. 1 (1) , 8
- https://doi.org/10.1186/1754-6834-1-8
Abstract
Background: A metabolic regulation study was performed, based upon measurements of enzymatic activities, fermentation performance, and RT-PCR analysis of pathways related to central carbon metabolism, in an ethanologenic Escherichia coli strain (CCE14) derived from lineage C. In comparison with previous engineered strains, this E coli derivative has a higher ethanol production rate in mineral medium, as a result of the elevated heterologous expression of the chromosomally integrated genes encoding PDC Zm and ADH Zm (pyruvate decarboxylase and alcohol dehydrogenase from Zymomonas mobilis). It is suggested that this behavior might be due to lineage differences between E. coli W and C. Results: This study demonstrated that the glycolytic flux is controlled, in this case, by reactions outside glycolysis, i.e., the fermentative pathways. Changes in ethanol production rate in this ethanologenic strain result in low organic acid production rates, and high glycolytic and ethanologenic fluxes, that correlate with enhanced transcription and enzymatic activity levels of PDC Zm and ADH Zm . Furthermore, a higher ethanol yield (90% of the theoretical) in glucose-mineral media was obtained with CCE14 in comparison with previous engineered E. coli strains, such as KO11, that produces a 70% yield under the same conditions. Conclusion: Results suggest that a higher ethanol formation rate, caused by ahigher PDC Zm and ADH Zm activities induces a metabolic state that cells compensate through enhanced glucose transport, ATP synthesis, and NAD-NADH+H turnover rates. These results show that glycolytic enzymatic activities, present in E. coli W and C under fermentative conditions, are sufficient to contend with increases in glucose consumption and product formation rates.Keywords
This publication has 76 references indexed in Scilit:
- Specific Ethanol Production Rate in Ethanologenic Escherichia coli Strain KO11 Is Limited by Pyruvate DecarboxylaseMicrobial Physiology, 2008
- Metabolic transcription analysis of engineered Escherichia coli strains that overproduce L-phenylalanineMicrobial Cell Factories, 2007
- Glycolysis and the regulation of glucose transport in Lactococcus lactis spp. lactis in batch and fed-batch cultureMicrobial Cell Factories, 2007
- Low salt medium for lactate and ethanol production by recombinant Escherichia coli BBiotechnology Letters, 2006
- Alcoholic fermentation of carbon sources in biomass hydrolysates by Saccharomyces cerevisiae: current statusAntonie van Leeuwenhoek, 2006
- Characterization of the molecular mechanisms involved in the differential production of erythrose‐4‐phosphate dehydrogenase, 3‐phosphoglycerate kinase and class II fructose‐1,6‐bisphosphate aldolase in Escherichia coliMolecular Microbiology, 2005
- Analysis of Relative Gene Expression Data Using Real-Time Quantitative PCR and the 2−ΔΔCT MethodMethods, 2001
- Oxygen- and Growth Rate-Dependent Regulation of Escherichia coli Fumarase (FumA, FumB, and FumC) ActivityJournal of Bacteriology, 2001
- Fermentations with New Recombinant OrganismsBiotechnology Progress, 1999
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976