Designing an Escherichia coli Strain for Phenylalanine Overproduction by Metabolic Engineering

The phenylalanine pathway flux is controlled by two types of regulators, those that are specific to the pathway, as well as by global regulators. In order to demonstrate the importance of these global regulators, we first removed the pathway-specific regulators using all possible combinations of gen...

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Bibliographic Details
Published in:Molecular biotechnology 2017-05, Vol.59 (4-5), p.168-178
Main Authors: Tyagi, Neetu, Saini, Deepti, Guleria, Richa, Mukherjee, Krishna Jyoti
Format: Article
Language:English
Subjects:
Biochemistry
Biological Techniques
Biology
Biotechnology
Cell Biology
Chemistry
Chemistry and Materials Science
Computer Simulation
E coli
Escherichia coli
Escherichia coli - genetics
Escherichia coli - metabolism
Genetic Enhancement - methods
Human Genetics
Metabolic Engineering - methods
Metabolic Flux Analysis - methods
Metabolic Networks and Pathways - physiology
Models, Biological
Original Paper
Phenylalanine - biosynthesis
Phenylalanine - isolation & purification
Protein Science
Up-Regulation - genetics
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Summary:The phenylalanine pathway flux is controlled by two types of regulators, those that are specific to the pathway, as well as by global regulators. In order to demonstrate the importance of these global regulators, we first removed the pathway-specific regulators using all possible combinations of gene knockouts and knockins. We found that genes like aroG fbr performed best individually as well as in combination with other genes, while other genes like tyrA and tyrR worked only in combination with other modifications. Knocking in the tktA gene under a tyrR promoter and knocking out pykF further increased phenylalanine production demonstrating that the supply of precursor via PEP and E4P is also a rate-limiting step. Finally, we tested the role of global regulators on this deregulated pathway and found that Fis overexpression helps in both enhancing and sustaining the flux through this pathway. This work opens up the possibility of using global regulators in synergy with pathway-specific modifications to enhance product yields.
ISSN:1073-6085
1559-0305
DOI:10.1007/s12033-017-9999-5