Project description:Ciprofloxacin, an inhibitor of bacterial gyrase and topoisomerase IV, was shown to inhibit growth of C. glutamicum with concomitant excretion of L-glutamate. C. glutamicum strains overproducing L-lysine, L-arginine, L-ornithine, and putrescine, respectively, produced L-glutamate instead of the desired amino acid when exposed to ciprofloxacin. Even in the absence of the putative L-glutamate exporter gene yggB, ciprofloxacin effectively triggered L-glutamate production. When C. glutamicum wild type was cultivated under nitrogen-limiting conditions, 2-oxoglutarate rather than L-glutamate was produced as consequence of exposure to ciprofloxacin. Transcriptome analysis revealed that ciprofloxacin increased RNA levels of genes involved in DNA synthesis, repair and modification. Enzyme assays showed that 2-oxoglutarate dehydrogenase activity was decreased due to ciprofloxacin addition. Here, it was shown for the first time that production of L-glutamate by C. glutamicum may be triggered by an inhibitor of DNA synthesis and L-glutamate titers of up to 37 ± 1 mM and a substrate specific L-glutamate yield of 0.13 g/g were reached.
Project description:For the establishment of synthetic microbial communities comprising complementary auxotrophic strains, transport processes for common goods are extremely important. Most auxotrophic strains reach wild type level growth with external supplementation of the required metabolite. One exception was the tryptophan auxotrophic strain Corynebacterium glutamicum ΔTRP ΔtrpP, which grew about 35% slower than the wild type in supplemented minimal medium. Corynebacterium glutamicum ΔTRP ΔtrpP lacks the whole tryptophan biosynthesis cluster (TRP) as well as the putative tryptophan transporter TrpP. We wanted to explore the role of TrpP in tryptophan transport or synthesis and to unravel the cause for the growth limitation of the auxotrophic strain.
Project description:Strains: non-producing refernece strain pXMJ19 (CR099 pXMJ19; Goldbeck et al., 2021) and Pediocin-producer pxMJ19 ped (CR099 pXMJ19 Ptac pedACDCg, Goldbeck et al., 2021) Pediocin-producing and non-producing strains of Corynebacterium glutamicum were compared in a whole genome microarray analysis setup in order to identify potential strain optimization targets
Project description:Metabolically engineered Corynebacterium glutamicum strains were constructed for the enhanced production of L-arginine, and their gene expression profiles were investigated
Project description:Metabolically engineered Corynebacterium glutamicum strains were constructed for the enhanced production of L-arginine, and their gene expression profiles were investigated Gene expression profiles of two C. glutamicum strains AR2 and AR6 were examined for the 3043 genes twice.
Project description:C. glutamicum strains adapted to higher growth temperatures were obtained through an adaptive laboratory evolution experiment. To elucidate molecular basis for thermotolerance acquired by the evolved strains, we examined transcriptional responses of the evolved and parental strains to thermal stress using microarray technology.
Project description:To identify genes which are differentially expressed in Corynebacterium glutamicum in the cg2699 deletion strain, we performed DNA microarray analyses of C. glutamicum Δcg2699 compared to the WT.
Project description:To identify genes which are differentially expressed in Corynebacterium glutamicum in the cg2460 deletion strain, we performed DNA microarray analyses of C. glutamicum Δcg2460 compared to the WT.
