Format

Send to

Choose Destination
Metab Eng. 2011 Jan;13(1):76-81. doi: 10.1016/j.ymben.2010.10.006. Epub 2010 Oct 30.

Manipulating redox and ATP balancing for improved production of succinate in E. coli.

Author information

1
Department of Chemical and Biological Engineering, University of Colorado, UCB 424, Boulder, CO 80309, USA.

Abstract

Redox and energy balance plays a key role in determining microbial fitness. Efforts to redirect bacterial metabolism often involve overexpression and deletion of genes surrounding key central metabolites, such as pyruvate and acetyl-coA. In the case of metabolic engineering of Escherichia coli for succinate production, efforts have mainly focused on the manipulation of key pyruvate metabolizing enzymes. E. coli AFP111 strain lacking ldhA, pflB and ptsG encoded activities accumulates acetate and ethanol as well as shows poor anaerobic growth on rich and minimal media. To address these issues, we first deleted genes (adhE, ackA-pta) involved in byproduct formation downstream of acetyl-CoA followed by the deletion of iclR and pdhR to activate the glyoxylate pathway. Based on data from these studies, we hypothesized that the succinate productivity was limited by the insufficient ATP generation. Genome-scale thermodynamics-based flux balance analysis indicated that overexpression of ATP-forming PEPCK from Actinobacillus succinogenes in an ldhA, pflB and ptsG triple mutant strain could result in an increase in biomass and succinate flux. Testing of this prediction confirmed that PEPCK overexpression resulted in a 60% increase in biomass and succinate formation in the ldhA, pflB, ptsG mutant strain.

PMID:
21040799
DOI:
10.1016/j.ymben.2010.10.006
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center