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Biotechnol Bioeng. 2012 Aug;109(8):2070-81. doi: 10.1002/bit.24486. Epub 2012 Mar 22.

Improved L-lysine production with Corynebacterium glutamicum and systemic insight into citrate synthase flux and activity.

Author information

1
Institute of Bio- and Geosciences, Biotechnology, Systemic Microbiology, Forschungszentrum Jülich GmbH, Jülich, Germany.

Abstract

We here developed a series of Corynebacterium glutamicum strains with gradual decreased specific citrate synthase (CS) activity and quantified in a multifaceted approach the consequences of residual activity on the transcriptome, metabolome, and fluxome level as well as on L-lysine formation and growth. We achieved an intended gradual L-lysine yield increase and recognized and overcame further new limitations in the L-lysine biosynthesis pathway to result in a strain with the highest yield reported so far when assayed under comparable conditions. As a non-intended outcome, a detailed flux analysis revealed an almost constant flux through CS at 10% remaining CS activity, whereas the metabolome data revealed an increase in the oxaloacetate and acetyl-CoA concentrations. Hence reduced CS activity is apparently efficiently buffered by increased concentrations of CS substrates, implying a certain robustness of the central metabolism in response of the imposed gene expressions.

PMID:
22392073
DOI:
10.1002/bit.24486
[Indexed for MEDLINE]

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