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Improved Production of Tryptophan in Genetically Engineered Escherichia coli with TktA and PpsA Overexpression
- Source :
- Journal of Biomedicine and Biotechnology, Vol 2012 (2012), Journal of Biomedicine and Biotechnology
- Publication Year :
- 2012
- Publisher :
- Hindawi Limited, 2012.
-
Abstract
- Intracellular precursor supply is a critical factor for amino acid productivity. In the present study,ppsAandtktAgenes were overexpressed in genetically engineeredEscherichia colito enhance the availability of two precursor substrates, phosphoenolpyruvate and erythrose-4-phosphate. The engineered strain, TRTH0709 carrying pSV709, produced 35.9 g/L tryptophan from glucose after 40 h in fed-batch cultivation. The two genes were inserted, independently or together, into a low-copy-number expression vector (pSTV28) and transferred to TRTH0709. Fed-batch fermentations at high cell densities of the recombination strains revealed that overexpression of theppsAgene alone does not significantly increase tryptophan yield. On the other hand, overexpression of thetktAgene, alone or with theppsAgene, could further improve tryptophan yield to a final tryptophan titer of 37.9 and 40.2 g/L, respectively. These results represent a 5.6% and 11.9% enhancement over the titer achieved by TRTH0709. No evident genetic modifications leading to growth impairment were observed.
- Subjects :
- Article Subject
Pyruvate Synthase
Health, Toxicology and Mutagenesis
lcsh:Biotechnology
Carboxylic Acids
lcsh:Medicine
Biology
medicine.disease_cause
Plasmid
lcsh:TP248.13-248.65
Pyruvic Acid
Genetics
medicine
Escherichia coli
Cloning, Molecular
Molecular Biology
Gene
chemistry.chemical_classification
Expression vector
Escherichia coli Proteins
lcsh:R
Tryptophan
General Medicine
Amino acid
Titer
Glucose
chemistry
Biochemistry
Fermentation
Molecular Medicine
Transketolase
Phosphoenolpyruvate carboxykinase
Genetic Engineering
Biotechnology
Research Article
Plasmids
Subjects
Details
- Language :
- English
- ISSN :
- 11107251 and 11107243
- Volume :
- 2012
- Database :
- OpenAIRE
- Journal :
- Journal of Biomedicine and Biotechnology
- Accession number :
- edsair.doi.dedup.....829cbdef18b4f1ac90232277f3c21974