Sunday, April 29, 2007

Metabolic engineering of Escherichia coli for L-valine production

Jin Hwan Park, Kwang Ho Lee, Tae Yong Kim, Hyohak Song, and Sang Yup Lee. Metabolic and Biomolecular Engineering National Research Laboratory, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon, South Korea

The L-valine production strain of Escherichia coli was constructed by rational metabolic engineering. Feedback inhibition of ilvH was removed by site-directed mutagenesis and the native promoter containing the transcriptional attenuator leader region of the ilvGMEDA and ilvBN operon was replaced with the stronger tac promoter. ilvA, leuA and panB were deleted to provide more available substrate for L-valine biosynthesis. The base strain harboring pKKilvBN gave 11.2 mM of L-valine within 18 hours of batch fermentation. Transcriptome analysis was performed to elucidate the effect of L-valine production on the cellular physiology during batch fermentation. The stepwise improvement from the base strain was carried out. The present study highlights the success of rational metabolic engineering for the production of L-valine by E. coli.
[This work was supported by a grant from the Korean Ministry of Science and Technology (Korean Systems Biology Research Grant, M10309020000-03B5002-00000). Further support by the LG Chem Chair Professorship is appreciated.]