fulltext.study @t Gmail

Co-expression of feedback-resistant threonine dehydratase and acetohydroxy acid synthase increase l-isoleucine production in Corynebacterium glutamicum

Paper ID Volume ID Publish Year Pages File Format Full-Text
31569 44819 2012 9 PDF Available
Title
Co-expression of feedback-resistant threonine dehydratase and acetohydroxy acid synthase increase l-isoleucine production in Corynebacterium glutamicum
Abstract

Threonine dehydratase and acetohydroxy acid synthase are critical enzymes in the l-isoleucine biosynthesis pathway of Corynebacterium glutamicum, but their activities are usually feedback-inhibited. In this study, we characterized a feedback-resistant threonine dehydratase and an acetohydroxy acid synthase from an l-isoleucine producing strain C. glutamicum JHI3-156. Sequence analysis showed that there was only a single amino acid substitution (Phe383Val) in the feedback-resistant threonine dehydratase, and there were three mutated amino acids (Pro176Ser, Asp426Glu, and Leu575Trp) in the big subunit of feedback-resistant acetohydroxy acid synthase. The mutated threonine dehydratase over-expressed in E. coli not only showed completely resistance to l-isoleucine inhibition, but also showed enhanced activity. The mutated acetohydroxy acid synthase over-expressed in E. coli showed more resistance to l-isoleucine inhibition than the wild type. Over-expression of the feedback-resistant threonine dehydratase or acetohydroxy acid synthase in C. glutamicum JHI3-156 led to increase of l-isoleucine production; co-expression of them in C. glutamicum JHI3-156 led to 131.7% increase in flask cultivation, and could produce 30.7 g/L l-isoleucine in 72-h fed-batch fermentation. These results would be useful to enhance l-isoleucine production in C. glutamicum.

► Mutant TD and AHAS from JHI3-156 were characterized. ► Mutant TD was 100% resistant to l-isoleucine inhibition. ► The activity of mutant TD was enhanced in the presence of l-isoleucine. ► Overexpression of mutant TD or AHAS increased l-isoleucine production. ► l-isoleucine could reach 30.7 g/L when mutant TD and AHAS co-expressed.

Keywords
Corynebacterium glutamicum; l-isoleucine; ilvA; ilvBN; Feedback inhibition; Threonine dehydratase; Acetohydroxy acid synthase
First Page Preview
Co-expression of feedback-resistant threonine dehydratase and acetohydroxy acid synthase increase l-isoleucine production in Corynebacterium glutamicum
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
Publisher
Database: Elsevier - ScienceDirect
Journal: Metabolic Engineering - Volume 14, Issue 5, September 2012, Pages 542–550
Authors
, , , , , ,
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