Characteristics of methionine production by an engineered Corynebacterium glutamicum strain.
Metab Eng
; 9(4): 327-36, 2007 Jul.
Article
em En
| MEDLINE
| ID: mdl-17604670
ABSTRACT
A methionine-producing strain was derived from a lysine-producing Corynebacterium glutamicum through a process of genetic manipulation in order to assess its potential to synthesize and accumulate methionine during growth. The strain carries a deregulated hom gene (hom(FBR)) to abolish feedback inhibition of homoserine dehydrogenase by threonine and a deletion of the thrB gene (delta thrB) to abolish threonine synthesis. The constructed C. glutamicum MH20-22B/hom(FBR)/delta thrB strain accumulated 2.9 g/l of methionine by batch fermentation and showed resistance to methionine analogue ethionine at concentrations up to 30 mM. The growth of the strain was apparently impaired as a result of the accumulation of methionine biosynthetic intermediate, homocysteine. Production assays also revealed that the accumulation of methionine in the growth medium was transient and declined as the carbon source was depleted. During the period of methionine disappearance, the methionine biosynthetic genes were completely repressed in the engineered strains but not in the parental strain. After all, we have not only successfully constructed a methionine-producing C. glutamicum strain by genetic manipulation, but also revealed cellular constraints in attaining high yield and productivity.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Regulação Bacteriana da Expressão Gênica
/
Corynebacterium glutamicum
/
Metionina
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article