Open Access

ARTICLE

Co-ordinated combination of Embden-Meyerhof-Parnas pathway and pentose phosphate pathway in Escherichia coli to promote L-tryptophan production

by SHUAI LIU¹, JIANZHONG XU^1,*, TINGSHAN LIU¹, ZHIMING RAO², WEIGUO ZHANG^1,*

1 The Key Laboratory of Industrial Biotechnology, Ministry of Education, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, 214122, China
2 National Engineering Laboratory for Cereal Fermentation Technology (NELCF), Jiangnan University, Wuxi, 214122, China

* Corresponding Authors: JIANZHONG XU. Email: ; WEIGUO ZHANG. Email:

BIOCELL 2022, 46(10), 2303-2313. https://doi.org/10.32604/biocell.2022.020899

Received 17 December 2021; Accepted 17 March 2022; Issue published 13 June 2022

Abstract

In this study, phosphoenolpyruvate and erythrose-4-phosphate are efficiently supplied by collaborative design of Embden-Meyerhof-Parnas (EMP) pathway and pentose phosphate (PP) pathway in Escherichia coli, thus increasing the L-tryptophan production. Firstly, the effects of disrupting EMP pathway on L-tryptophan production were studied, and the results indicated that the strain with deletion of phosphofructokinase A (i.e., E. coli JW-5 ΔpfkA) produced 23.4 ± 2.1 g/L of L-tryptophan production. However, deletion of phosphofructokinase A and glucosephosphate isomerase is not conducive to glucose consumption and cell growth, especially deletion of glucosephosphate isomerase. Next, the carbon flux in PP pathway was enhanced by introduction of the desensitized glucose-6-phosphate dehydrogenase (zwf) and 6-phosphogluconate dehydrogenase (gnd) and thus increasing the L-tryptophan production (i.e., 26.5 ± 3.2 g/L vs. 21.7 ± 1.3 g/L) without obviously changing the cell growth (i.e., 0.41 h⁻¹ vs. 0.44 h⁻¹) as compared with the original strain JW-5. Finally, the effects of co-modifying EMP pathway and PP pathway on L-tryptophan production were investigated. It was found that the strain with deletion of phosphofructokinase A as well as introduction of the desensitized zwf and gnd (i.e., E. coli JW-5 zwf243 gnd361 ΔpfkA) produced 31.9 ± 2.7 g/L of L-tryptophan, which was 47.0% higher than that of strain JW-5. In addition, the glucose consumption rate of strain JW-5 zwf243 gnd361 ΔpfkA was obviously increased despite of the bad cell growth as compared with strain JW-5. The results of this study have important reference value for the following application of metabolic engineering to improve aromatic amino acids producing strains.

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Keywords

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