원문정보
초록
영어
The L-valine producing strain of Escherichia coli was constructed by rational metabolic engineering and stepwise improvement based on transcriptome analysis and in silico gene knock-out simulation. Feedback inhibition of acetohydroxy acid synthase isoenzyme III by L-valine was removed by site-directed mutagenesis and the native promoter containing the transcriptional attenuator leader regions of the ilvGMEDA and ilvBN operon were replaced with the tac promoter. The ilvA, leuA and panB genes were deleted to make more precursors available for L-valine biosynthesis. This engineered Val strain harboring pKKilvBN, which overexpresses the ilvBN genes, produced 1.31 g/liter L-valine. Comparative transcriptome profiling combined with in silico gene knock-out simulation was used for the enhanced production of L-valine. The VAMF strain (Val ΔaceF Δmdh ΔpfkA) harboring pKBRilvBNCED and
pTrc184ygaZHlrp was able to produce 7.55 g/liter L-valine from 20 g/liter glucose, resulting in a high yield of 0.378 g L-valine per g glucose. The approaches described here can be a good example of systematically engineering strains for the enhanced production of amino acids. [This work was supported by the Korean Systems Biology Project of the Ministry of Science and
Technology (M10309020000-03B5002-00000). Further supports by the LG Chem Chair Professorship and KOSEF through the CUPS are appreciated].