Back to Search Start Over

Construction of an L-isoleucine overproducing strain of Escherichia coli K-12.

Authors :
Hashiguchi K
Takesada H
Suzuki E
Matsui H
Source :
Bioscience, biotechnology, and biochemistry [Biosci Biotechnol Biochem] 1999 Apr; Vol. 63 (4), pp. 672-9.
Publication Year :
1999

Abstract

The genes for a threonine deaminase that is resistant to feedback inhibition by L-isoleucine and for an active acetohydroxyacid synthase II were introduced by a plasmid into a L-threonine-producing recombinant strain of Escherichia coli K-12. Analysis of culture broth of the strain using 13C nuclear magnetic resonance suggested that alpha, beta-dihydroxy-beta-methylvalerate (DHMV) and alpha-keto-beta-methylvalerate (KMV), the third and the fourth intermediates in the L-isoleucine biosynthetic pathway from L-threonine, respectively, accumulated in the medium in amounts comparable to that of L-isoleucine. The ratio of accumulated L-isoleucine:DHMV:KMV were approximately 2:1:1. The concentration of accumulated L-isoleucine increased by twofold after the additional introduction of the genes for dihyroxyacid dehydratase (DH) and transaminase-B (TA-B), and the intermediates no longer accumulated. The resultant strain TVD5 accumulated 10 g/l of L-isoleucine from 40 g/l of glucose.

Details

Language :
English
ISSN :
0916-8451
Volume :
63
Issue :
4
Database :
MEDLINE
Journal :
Bioscience, biotechnology, and biochemistry
Publication Type :
Academic Journal
Accession number :
10361680
Full Text :
https://doi.org/10.1271/bbb.63.672