Effect of mufti-gene knockout of L-tryptophan transport system on L-tryptophan production in Escherichia coli.
- Author:
Zhijun ZHAO
1
;
Sheng CHEN
;
Dan WU
;
Jing WU
;
Jian CHEN
Author Information
1. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
- Publication Type:Journal Article
- MeSH:
Amino Acid Transport Systems;
genetics;
Biological Transport;
Escherichia coli;
genetics;
metabolism;
Escherichia coli Proteins;
genetics;
Fermentation;
Gene Knockout Techniques;
Membrane Transport Proteins;
genetics;
metabolism;
Mutant Proteins;
metabolism;
Tryptophan;
biosynthesis;
genetics;
metabolism
- From:
Chinese Journal of Biotechnology
2011;27(12):1765-1772
- CountryChina
- Language:Chinese
-
Abstract:
In Escherichia coli, uptake of L-tryptophan is done by three distinct permeases, encoded by mtr, tnaB, and aroP. Based on the mtr single-gene knockout, we constructed the mtr.tnaB and mtr.aroP double-gene knockout mutants and the mtr.tnaB.aroP triple-gene knockout mutant. The fermentation results showed that the mtr.tnaB and mtr.aroP knockout mutants produced 1.38 g/L and 1.27 g/L L-tryptophan, respectively, which was 17% and 9% higher than that of the mtr knockout mutant. However, the mtr.tnaB.aroP knockout mutant was significantly affected on cell growth and only produced 0.63 g/L L-tryptophan. During the fed-batch fermentation in a 3-L fermentor, the mtr.tnaB knockout mutant produced 12.2 g/L L-tryptophan, which was 27% higher than that of the mtr knockout mutant. This study demonstrates the effect of multi-gene knockouts of L-tryptophan transport system of Escherichia coli on the biosynthesis of L-tryptophan.
