Patent ID: 7915018

Claim:
A method for producing L-threonine which comprises cultivating an Escherichia coli in a culture medium to cause accumulation of the L-threonine in the culture medium, and isolating the L-threonine from the culture medium, wherein said Escherichia coli has been modified to enhance an activity of D-xylose permease derived from an Enterobacteriaceae by a method selected from the group consisting of: A) increasing the copy number of the gene encoding D-xylose permease, B) placing the gene encoding D-xylose permease under the control of a potent promoter, C) combinations thereof, wherein the culture medium contains glucose as the sole carbon source, and L-threonine production from glucose is improved due to enhancing the activity of D-xylose permease in said Escherichia coli.