These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effect of transport proteins on L-isoleucine production with the L-isoleucine-producing strain Corynebacterium glutamicum YILW.
    Author: Xie X, Xu L, Shi J, Xu Q, Chen N.
    Journal: J Ind Microbiol Biotechnol; 2012 Oct; 39(10):1549-56. PubMed ID: 22733295.
    Abstract:
    Previous studies have shown that the deletion of brnQ from the Corynebacterium glutamicum chromosome results in a significant reduction in L-isoleucine uptake rates, while overexpression of brnFE leads to enhanced L-isoleucine export rates. Given that net excretion rates would be an important factor for high titers of L-isoleucine accumulation, we have tested the notion that decreased L-isoleucine uptake combined with increased L-isoleucine excretion will further improve high-yield strains that are currently used for the industrial-scale production of L-isoleucine. To examine the effect of the two carriers on L-isoleucine accumulation in L-isoleucine producer C. glutamicum YILW, we constructed a brnQ deletion mutant (C. glutamicum YILW∆brnQ) and two brnFE overexpressors (C. glutamicum YILWpXMJ19brnFE and C. glutamicum YILW∆brnQpXMJ19brnFE). Compared to the original strain, the efflux rate of the brnQ mutant increased from 19.0 to 23.6 nmol min(-1) mg (dry wt)(-1) and its L-isoleucine titer increased from 154.3 mM (20.2 g l(-1)) to 170.3 mM (22.3 g l(-1)). The efflux rates of C. glutamicum YILWpXMJ19brnFE and C. glutamicum YILW∆brnQpXMJ19brnFE were 33.5 and 39.1 nmol min(-1) mg (dry wt)(-1), and their L-isoleucine production titers were 197.2 mM (25.9 g l(-1)) and 221.0 mM (29.0 g l(-1)), respectively. Our results suggest that modifications of the transport system could provide a promising avenue for further increasing L-isoleucine yield in the L-isoleucine producer.
    [Abstract] [Full Text] [Related] [New Search]