Reducing lactate secretion by ldhA Deletion in L-glutamate- producing strain Corynebacterium glutamicum GDK-9
AUTOR(ES)
Zhang, Dalong, Guan, Dan, Liang, Jingbo, Guo, Chunqian, Xie, Xixian, Zhang, Chenglin, Xu, Qingyang, Chen, Ning
FONTE
Braz. J. Microbiol.
DATA DE PUBLICAÇÃO
2014-12
RESUMO
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.
Documentos Relacionados
- L-Glutamate production by lysozyme-sensitive Corynebacterium glutamicum ltsA mutant strains
- Functional Replacement of the Escherichia colid-(−)-Lactate Dehydrogenase Gene (ldhA) with the l-(+)-Lactate Dehydrogenase Gene (ldhL) from Pediococcus acidilactici†
- A Mutation in the Corynebacterium glutamicum ltsA Gene Causes Susceptibility to Lysozyme, Temperature-Sensitive Growth, and l-Glutamate Production
- Development of L-glutamate- and glycine-activated currents in spinal cord neurones during early chick embryogenesis.
- Metabolic Engineering To Produce Tyrosine or Phenylalanine in a Tryptophan-Producing Corynebacterium glutamicum Strain