Improvement of Escherichia coli production strains by modification of the phosphoenolpyruvate:sugar phosphotransferase system

The application of metabolic engineering in Escherichia coli has resulted in the generation of strains with the capacity to produce metabolites of commercial interest.

Category: Microbial-Cell-Factories

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The application of metabolic engineering in Escherichia coli has resulted in the generation of strains with the capacity to produce metabolites of commercial interest. Biotechnological processes with these engineered strains frequently employ culture media containing glucose as the carbon and energy source. In E. coli, the phosphoenolpyruvate:sugar phosphotransferase system (PTS) transports glucose when this sugar is present at concentrations similar to those used in production fermentations. This protein system is involved in phosphoenolpyruvate-dependent sugar transport and carbon catabolite repression. Its activity has an important impact on carbon flux distribution in the phosphoenolpyruvate and pyruvate nodes. These characteristics impose metabolic and regulatory constraints that can hinder strain productivity. For this reason, PTS has been a target for modification with the purpose of strain improvement. In this review, the characteristics of PTS most relevant to strain performance and the different strategies of PTS modification for strain improvement are discussed. Functional replacement of PTS by alternative phosphoenolpyruvate-independent uptake and phosphorylation activities has resulted in significant improvements in product yield from glucose and productivity for several classes of metabolites. In addition, inactivation of PTS components has been applied successfully as a strategy to abolish carbon catabolite repression, resulting in E. coli strains that use more efficiently sugar mixtures, such as those obtained from lignocellulosic hydrolysates. http://www.microbialcellfactories.com/content/4/1/14

Guillermo Gosset

Microbial Cell Factories 2005, 4:14

2005-05-16

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