Reducing lactate secretion by ldhA Deletion in L-glutamate- producing strain Corynebacterium glutamicum GDK-9
Braz. j. microbiol
;
45(4): 1477-1483, Oct.-Dec. 2014. ilus, graf, tab
Article
in English
| LILACS
| ID: lil-741303
ABSTRACT
L-lactate is one of main byproducts excreted in to the fermentation medium. To improve L-glutamate production and reduce L-lactate accumulation, L-lactate dehydrogenase-encoding gene ldhA was knocked out from L-glutamate producing strain Corynebacterium glutamicum GDK-9, designated GDK-9ΔldhA. GDK-9ΔldhA produced approximately 10.1% more L-glutamate than the GDK-9, and yielded lower levels of such by-products as α-ketoglutarate, L-lactate and L-alanine. Since dissolved oxygen (DO) is one of main factors affecting L-lactate formation during L-glutamate fermentation, we investigated the effect of ldhA deletion from GDK-9 under different DO conditions. Under both oxygen-deficient and high oxygen conditions, L-glutamate production by GDK-9ΔldhA was not higher than that of the GDK-9. However, under micro-aerobic conditions, GDK-9ΔldhA exhibited 11.61% higher L-glutamate and 58.50% lower L-alanine production than GDK-9. Taken together, it is demonstrated that deletion of ldhA can enhance L-glutamate production and lower the unwanted by-products concentration, especially under micro-aerobic conditions.
Full text:
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Index:
LILACS (Americas)
Main subject:
Gene Deletion
/
Glutamic Acid
/
Lactic Acid
/
Corynebacterium glutamicum
/
Metabolic Engineering
/
L-Lactate Dehydrogenase
Language:
English
Journal:
Braz. j. microbiol
Journal subject:
Microbiology
Year:
2014
Type:
Article
/
Project document
Affiliation country:
China
Institution/Affiliation country:
Tianjin University of Science and Technology/CN
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