Modification of tryptophan transport system and its impact on production of l-tryptophan in Escherichia coli

► Acidic acetonitrile for intracellular tryptophan extraction was adopted. ► Changes of transport systems for l-tryptophan leaded to a higher yield of l-tryptophan by metabolic flux redistribution. ► The strengthen of exporter was more effective than other modifications in the fermentation of l-tryptophan.