Dynamics of glutamate synthesis and excretion fluxes in batch and continuous cultures of temperature-triggered Corynebacterium glutamicum

2004 ◽  
Vol 27 (3) ◽  
pp. 153-162 ◽  
Author(s):  
Davin Uy ◽  
Stéphane Delaunay ◽  
Jean-Louis Goergen ◽  
Jean-Marc Engasser
Keyword(s):  
Corynebacterium Glutamicum ◽  
Continuous Cultures ◽  
Glutamate Synthesis

scholarly journals Modular control of multiple pathways of Corynebacterium glutamicum for 5-aminolevulinic acid production

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fanglan Ge ◽  
Xiaokun Li ◽  
Qingrong Ge ◽  
Di Zhu ◽  
Wei Li ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Carbon Flux ◽  
Large Scale ◽  
Aminolevulinic Acid ◽  
Protoporphyrin Ix ◽  
Tca Cycle ◽  
Strain Engineering ◽  
C4 Pathway ◽  
Encoding Gene ◽  
Glutamate Synthesis

Abstract5-aminolevulinic acid (ALA) has broad potential applications in the medical, agricultural and food industries. Several strategies have been implemented successfully to try to improve ALA synthesis. Nonetheless, the low yield has got in the way of large-scale bio-manufacture of 5-ALA. In this study, we explored strain engineering strategies for high‐level 5‐ALA production in Corynebacterium glutamicum F343 using the C4 pathway. Initially, the glutamate dehydrogenase-encoding gene gdhA was deleted to reduce glutamate yield. Then the C4 pathway was introduced in the gdhA mutant strain F2-A (∆gdhA + hemA), resulting in a 5-ALA yield of up to 3.2 g/L. Furthermore, the accumulations of downstream metabolites such as heme, porphobilinogen, and protoporphyrin IX, were decreased. After evaluating the mechanisms of this synthetic pathway by RNA-Seq, the results showed that genes involved in both the C5 pathway and heme pathways were down-regulated in strain F2-A (∆gdhA + hemA). Interestingly, upstream genes of succinyl-CoA in the tricarboxylic acid (TCA) cycle, such as icd, lpdA, were up-regulated, while its downstream genes, including sucC, sucD, sdhB, sdhA, sdhCD, were down-regulated. These changes amplify the sources of succinyl-CoA and reduce its expenditure, before pulling the carbon flux to produce 5-ALA. Furthermore, the down-regulation of most genes of the heme pathway could reduce the drainage of 5‐ALA, which further enhance its accumulation. To alleviate competition between glyoxylate and the TCA cycle, the isocitrate dehydrogenase-encoding gene aceA was also knocked out, resulting in 3.86 g/L of 5‐ALA. Finally, the fermentation conditions were optimized, resulting in a maximum 5-ALA yield of 5.6 g/L. Overall, the blocking of the glutamate synthesis pathway could be a powerful strategy to re-allocate the carbon flux to produce 5-ALA. It could also enable the efficient synthesis of other TCA derivatives in C. glutamicum.

CarR, a MarR-family regulator from Corynebacterium glutamicum, modulated antibiotic and aromatic compound resistance

2019 ◽  
Vol 476 (21) ◽  
pp. 3141-3159 ◽  
Author(s):  
Meiru Si ◽  
Can Chen ◽  
Zengfan Wei ◽  
Zhijin Gong ◽  
GuiZhi Li ◽  
...  
Keyword(s):  
Stress Response ◽  
Ligand Binding ◽  
Corynebacterium Glutamicum ◽  
Conformational Changes ◽  
Cysteine Oxidation ◽  
Transcriptional Regulatory ◽  
Ligand Free ◽  
Redox Sensing

Abstract MarR (multiple antibiotic resistance regulator) proteins are a family of transcriptional regulators that is prevalent in Corynebacterium glutamicum. Understanding the physiological and biochemical function of MarR homologs in C. glutamicum has focused on cysteine oxidation-based redox-sensing and substrate metabolism-involving regulators. In this study, we characterized the stress-related ligand-binding functions of the C. glutamicum MarR-type regulator CarR (C. glutamicum antibiotic-responding regulator). We demonstrate that CarR negatively regulates the expression of the carR (ncgl2886)–uspA (ncgl2887) operon and the adjacent, oppositely oriented gene ncgl2885, encoding the hypothetical deacylase DecE. We also show that CarR directly activates transcription of the ncgl2882–ncgl2884 operon, encoding the peptidoglycan synthesis operon (PSO) located upstream of carR in the opposite orientation. The addition of stress-associated ligands such as penicillin and streptomycin induced carR, uspA, decE, and PSO expression in vivo, as well as attenuated binding of CarR to operator DNA in vitro. Importantly, stress response-induced up-regulation of carR, uspA, and PSO gene expression correlated with cell resistance to β-lactam antibiotics and aromatic compounds. Six highly conserved residues in CarR were found to strongly influence its ligand binding and transcriptional regulatory properties. Collectively, the results indicate that the ligand binding of CarR induces its dissociation from the carR–uspA promoter to derepress carR and uspA transcription. Ligand-free CarR also activates PSO expression, which in turn contributes to C. glutamicum stress resistance. The outcomes indicate that the stress response mechanism of CarR in C. glutamicum occurs via ligand-induced conformational changes to the protein, not via cysteine oxidation-based thiol modifications.

Expression of the NADP+-Dependent Formate Dehydrogenase Gene from Pseudomonas Increases the Lysine Production in Corynebacterium glutamicum

2019 ◽  
Vol 35 (6) ◽  
pp. 21-29
Author(s):  
T.E. Leonova ◽  
T.E. Shustikova ◽  
T.V. Gerasimova ◽  
Т.А. Ivankova ◽  
K.V. Sidorenko Sidorenko ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Formate Dehydrogenase ◽  
Ministry Of Education ◽  
Lysine Production ◽  
Simultaneous Formation ◽  
Resource Center ◽  
Formate Oxidation ◽  
Gene Coding ◽  
Dehydrogenase Gene ◽  
Lysine Synthesis

Thepsefdh_D221Q gene coding for a mutant formate dehydrogenase (PseFDG_D221Q) from Pseudomonas, which catalyzes the formate oxidation with the simultaneous formation of NADPH, has been expressed in the cells of lysine-producing Corynebacterium glutamicum strains. The psefdh_D221Q gene was introduced into С. glutamicum strains as part of an autonomous plasmid or was integrated into the chromosome with simultaneous inactivation of host formate dehydrogenase genes. It was shown that the С. glutamicum strains with NADP+ -dependent formate dehydrogenase have an increased level of L-lysine synthesis in the presence of formate, if their own formate dehydrogenase is inactivated. L-lysine, formate dehydrogenase, NADPH, Corynebacterium glutamicum The work was carried out using the equipment of the Multipurpose Scientific This work was carried out on the equipment of the Multipurpose Scientific Installation of «All-Russian Collection of Industrial Microorganisms», National Bio-Resource Center, NRC «Kurchatov Institute»- GosNIIgenetika. This work was financially supported by the Ministry of Education and Science of Russia (Unique Project Identifier - RFMEFI61017X0011).

Anaerobic Semi-Continuous Culture Biodegradation of Dichlorophenols Containing an Ortho Chlorine

1987 ◽  
Vol 22 (3) ◽  
pp. 427-436 ◽  
Author(s):  
S.E. Hrudey ◽  
E. Knettig ◽  
P.M. Fedorak ◽  
S.A. Daignault
Keyword(s):  
Activated Carbon ◽  
Continuous Culture ◽  
Chlorine Atom ◽  
Degradation Process ◽  
Anaerobic Sludge ◽  
Continuous Cultures ◽  
Complete Mineralization

Abstract Rapid and preferential dechlorination of the ortho chlorine from 2,6-, 2,4- and 2,3- dichlorophenol substrates was observed in semi-continuous cultures inoculated with 50% unacclimated anaerobic sludge. The rate of further dechlorination depended on the position of the second chlorine atom. The dechlorination rates for the second chlorine ranked ortho > para > meta. Complete mineralization to methane was only observed in cultures fed 2,6-dichlorophenol. Addition of activated carbon to the anaerobic cultures showed some benefit to the degradation process.

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