Pathway engineering for production of aromatics in Escherichia coli: Confirmation of stoichiometric analysis by independent modulation of AroG, TktA, and Pps activities
- Texas A and M Univ., College Station, TX (United States). Dept. of Chemical Engineering
The synthesis of 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) is the first commitment of resources toward aromatics production in Escherichia coli. DAHP is produced during the condensation reaction between phosphenolpyruvate (PEP) and erythrose 4-phosphate (E4P) catalyzed by DAHP synthases (coded by aroF, aroG, and aroH). Stoichiometric analysis has shown a severe PEP limitation in the theoretical yield of DAHP production from glucose due to the phosphotransferase system (PTS) for sugar uptake. In the present study the authors confirm the predictions of the stoichiometric analysis by introducing pps, tktA, and aroG into vectors under independently controlled promoters, In glucose medium, although TktA has some positive effect on the final DAHP concentration, it has no effect on the yield (percent conversion). With Pps overexpression, the DAHP concentration produced from glucose is increased almost twofold and the yield is approaching the theoretical maximum, the final DAHP concentration and the yield are completely determined by the AroG activity. TktA and Pps play no or insignificant roles, and the yield can reach the theoretical maximum without overexpression of these two enzymes. The results shown hare are important for both rational design of metabolic pathways and industrial production of aromatics such as tryptophan, phenylalanine, indigo, quinic acid, and catechol.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 64508
- Journal Information:
- Biotechnology and Bioengineering, Vol. 46, Issue 4; Other Information: PBD: 20 May 1995
- Country of Publication:
- United States
- Language:
- English
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