Improved L-threonine production of Escherichia coli mutant by optimization of culture conditions.
J Biosci Bioeng
; 101(2): 127-30, 2006 Feb.
Article
em En
| MEDLINE
| ID: mdl-16569607
ABSTRACT
L-threonine production was investigated in a minimal salt medium using L-threonine-overproducing Escherichia coli MT201, derived from E. coli K-12. It was observed that dry cell weight reached 12.5 g/l with 15.9 g/lL-threonine. To increase dry cell weight and L-threonine production, the fermentation process was optimized. When biotin was added as growth factor, L-threonine production reached 52.0 g/l from 15.9 g/l without biotin. Dry cell weight and L-threonine production were further increased by continuous feeding of the feed media with an optimized L-methionine concentration (5.0 g/l). However, high-cell-density culture caused oxygen-limited condition, which resulted in the accumulation of organic acids. To overcome this problem, oxygen-enriched air was supplied to the fermentor with the minimal salt medium. Under these optimal conditions, we achieved an L-threonine production of 80.2 g/l in the minimal salt medium.
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Base de dados:
MEDLINE
Assunto principal:
Treonina
/
Microbiologia Industrial
/
Meios de Cultura
/
Escherichia coli
/
Mutação
Idioma:
En
Ano de publicação:
2006
Tipo de documento:
Article