Patent 7700328 was granted and assigned to E.I. Du Pont De Nemours And Company on April, 2010 by the United States Patent and Trademark Office.
An enteric bacterial strain was engineered to over-produce L-tyrosine using a one-step method. The pheA-tyrA chromosomal region of the bacterial genome was replaced with an engineered chromosomal segment, resulting in inactivation of the pheA coding region and strong expression of the tyrA coding region, resulting in high levels of L-tyrosine production.