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

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.

Activity of exporters of Escherichia coli in Corynebacterium glutamicum, and their use to increase L-threonine production.

L-Threonine is an important biotechnological product and Corynebacterium glutamicum is able to synthesize and accumulate this amino acid to high intracellular levels. We here use four exporters of Escherichia coli and show that three of them operate in C. glutamicum, with RhtA and RhtC being the most effective.