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Metabolic engineering of the L-valine biosynthesis pathway in Corynebacterium glutamicum using promoter activity modulation

Paper ID Volume ID Publish Year Pages File Format Full-Text
24489 43519 2009 8 PDF Available
Title
Metabolic engineering of the L-valine biosynthesis pathway in Corynebacterium glutamicum using promoter activity modulation
Abstract

The previously constructed strain Corynebacterium glutamicumilvNM13 with acetohydroxy acid synthase, resistant to inhibition by all three branched-chain amino acids (L-valine, L-isoleucine and L-leucine), was used as a basis to develop a new type of valine producer by genetic engineering. The main strategy was to modulate expression of the genes involved in the biosynthesis of branched-chain amino acids. The activity of the promoters P-ilvD (dihydroxyacid dehydratase) and P-ilvE (transaminase) was up-modulated and the activity of the promoters P-ilvA (threonine deaminase) and P-leuA (isopropylmalate synthase) was down-modulated by site-directed mutagenesis. A constructed weak promoter of ilvA (or leuA), which was introduced into the C. glutamicum chromosome via a gene-replacement technique reduced the biosynthetic rate of isoleucine (or leucine), which lowered the mutant growth rate and increased valine production. Overexpression of ilvD and ilvE driven by the strong mutant promoters P-ilvDM7 and P-ilvEM6 resulted in an even higher level of valine production. Thus, the strain C. glutamicum ilvNM13 ΔpanB P-ilvAM1CG P-ilvDM7 P-ilvEM6, having all mutations constructed within the chromosome, produced 136 mM valine in a 48-h cultivation.

Keywords
Corynebacterium glutamicum; Valine production; Promoters; Mutagenesis
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Metabolic engineering of the L-valine biosynthesis pathway in Corynebacterium glutamicum using promoter activity modulation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 139, Issue 3, 5 February 2009, Pages 203–210
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us