In order to produce phenylalanine without tyrosine co-prodction, we constructed various temperature-controllable expression vectors by insertion of lower expression of the tyrA gene into plasmid pSY 130-14.
And tyrosine revertant to cultivate withou...
In order to produce phenylalanine without tyrosine co-prodction, we constructed various temperature-controllable expression vectors by insertion of lower expression of the tyrA gene into plasmid pSY 130-14.
And tyrosine revertant to cultivate without addition of tyrosine, was selected from Escherichia coli strain AT2471[tyrA,thi]by spontaneous mutation,
The strain AT2471 harbouring plasmid pSY 146A and the tyrosine revertant 5 harbouring plasmid pSY 111-14 produced 12g/ℓand 15g/ℓof phenylalanine respectively in 2.5ℓjar fermenter at a constant temperature of 39℃ after 55 hours cultivation.