| biogenic silver nanoparticles production and characterization from native stain of corynebacterium species and its antimicrobial activity. | in the present study, synthesis, characterization, and the antibacterial activity of silver nanoparticles from native isolate of corynebacterium glutamicum has been reported. silver nanoparticles were synthesized by challenging the dried biomass of c. glutamicum with aqueous diamine silver ([ag (nh3)(2)](+)) containing 1 mm agno3. synthesized silver nanoparticles (agnps) were characterized by ultraviolet-visible spectroscopy and energy-dispersive x-ray (edx) spectroscopy analysis. morphological ... | 2015 | 28324578 |
| optimization of fermentation upstream parameters and immobilization of corynebacterium glutamicum mh 20-22 b cells to enhance the production of l-lysine. | l-lysine is an essential amino acid with high commercial importance, as it has to be available in sufficient quantities in animal and human feeds to meet their nutritional requirement. as there is constant increase in l-lysine demand every year, to meet the increasing demand it is necessary to produce l-lysine in large scale. generally, l-lysine is produced by batch fermentation. in the present investigation, different fermentation process parameters such as fermentation time, ph, temperature, g ... | 2015 | 28324555 |
| comparative studies for the biotechnological production of l-lysine by immobilized cells of wild-type corynebacterium glutamicum atcc 13032 and mutant mh 20-22 b. | establishing a cost and time efficient approach for bioprocess optimization is desired but is challenging. in the present work, we have addressed the effectiveness of using immobilized cells for aerobic processes, behaviour of immobilized cells, optimization and upstream bioprocess analysis for the production of lysine by immobilized cells of corynebacterium glutamicum atcc 13032 and mh 20-22 b in stirred tank bioreactor. optimized operational conditions for maximal yield and productivity were d ... | 2015 | 28324528 |
| production of l-ornithine from sucrose and molasses by recombinant corynebacterium glutamicum. | sucrose and molasses are attractive raw materials for industrial fermentation. although corynebacterium glutamicum shows sucrose-utilizing activity, sucrose or molasses is only a fraction of carbon source used in the fermentation medium in most works. an engineered c. glutamicum strain was constructed for producing l-ornithine with sucrose or molasses as a sole carbon source by transferring mannheimia succiniciproducens β-fructofuranosidase gene (sacc). the engineered strain, c. glutamicum δape6 ... | 2015 | 25527174 |
| improvement of l-citrulline production in corynebacterium glutamicum by ornithine acetyltransferase. | in this study, corynebacterium glutamicum atcc 13032 was engineered to produce l-citrulline through a metabolic engineering strategy. to prevent the flux away from l-citrulline and to increase the expression levels of genes involved in the citrulline biosynthesis pathway, the argininosuccinate synthase gene (argg) and the repressor gene (argr) were inactivated. the engineered c. glutamicum atcc 13032 ∆argg ∆argr (cit 2) produced higher amounts of l-citrulline (5.43 g/l) compared to the wildtype ... | 2015 | 25492493 |
| production of 2-ketoisocaproate with corynebacterium glutamicum strains devoid of plasmids and heterologous genes. | 2-ketoisocaproate (kic), the last intermediate in l-leucine biosynthesis, has various medical and industrial applications. after deletion of the ilve gene for transaminase b in l-leucine production strains of corynebacterium glutamicum, kic became the major product, however, the strains were auxotrophic for l-isoleucine. to avoid auxotrophy, reduction of ilve activity by exchanging the atg start codon of ilve by gtg was tested instead of an ilve deletion. the resulting strains were indeed able t ... | 2015 | 25488800 |
| economically enhanced succinic acid fermentation from cassava bagasse hydrolysate using corynebacterium glutamicum immobilized in porous polyurethane filler. | an immobilized fermentation system, using cassava bagasse hydrolysate (cbh) and mixed alkalis, was developed to achieve economical succinic acid production by corynebacterium glutamicum. the c. glutamicum strains were immobilized in porous polyurethane filler (ppf). cbh was used efficiently as a carbon source instead of more expensive glucose. moreover, as a novel method for regulating ph, the easily decomposing nahco3 was replaced by mixed alkalis (naoh and mg(oh)2) for succinic acid production ... | 2014 | 25463799 |
| elimination of polyamine n-acetylation and regulatory engineering improved putrescine production by corynebacterium glutamicum. | corynebacterium glutamicum has been engineered for production of the polyamide monomer putrescine or 1,4-diaminobutane. here, n-acetylputrescine was shown to be a significant by-product of putrescine production by recombinant putrescine producing c. glutamicum strains. a systematic gene deletion approach of 18 (putative) n-acetyltransferase genes revealed that the cg1722 gene product was responsible for putrescine acetylation. the encoded enzyme was purified and characterized as polyamine n-acet ... | 2015 | 25449016 |
| l-serine overproduction with minimization of by-product synthesis by engineered corynebacterium glutamicum. | the direct fermentative production of l-serine by corynebacterium glutamicum from sugars is attractive. however, superfluous by-product accumulation and low l-serine productivity limit its industrial production on large scale. this study aimed to investigate metabolic and bioprocess engineering strategies towards eliminating by-products as well as increasing l-serine productivity. deletion of alat and avta encoding the transaminases and introduction of an attenuated mutant of acetohydroxyacid sy ... | 2015 | 25434811 |
| recent advances in the metabolic engineering of corynebacterium glutamicum for the production of lactate and succinate from renewable resources. | recent increasing attention to environmental issues and the shortage of oil resources have spurred political and industrial interest in the development of environmental friendly and cost-effective processes for the production of bio-based chemicals from renewable resources. thus, microbial production of commercially important chemicals is viewed as a desirable way to replace current petrochemical production. corynebacterium glutamicum, a gram-positive soil bacterium, is one of the most important ... | 2015 | 25424693 |
| metabolic engineering for improved production of ethanol by corynebacterium glutamicum. | recombinant corynebacterium glutamicum harboring genes for pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhb) can produce ethanol under oxygen deprivation. we investigated the effects of elevating the expression levels of glycolytic genes, as well as pdc and adhb, on ethanol production. overexpression of four glycolytic genes (pgi, pfka, gapa, and pyk) in c. glutamicum significantly increased the rate of ethanol production. overexpression of tpi, encoding triosephosphate isomerase, fu ... | 2015 | 25421564 |
| identification and expression analysis of a gene encoding a shikimate transporter of corynebacterium glutamicum. | shikimate can be utilized as the sole source of carbon and energy of corynebacterium glutamicum. although biosynthesis and degradation of shikimate are well characterized in c. glutamicum, the transport of shikimate has hardly been studied. a mutant strain deficient in cgr_2523 loses the ability to grow on shikimate as well as to consume extracellular shikimate, indicating that the gene is involved in shikimate utilization (designated shia). the hydropathy profile of the deduced amino acid seque ... | 2015 | 25406451 |
| expanding the regulatory network governed by the extracytoplasmic function sigma factor σh in corynebacterium glutamicum. | the extracytoplasmic function sigma factor σ(h) is responsible for the heat and oxidative stress response in corynebacterium glutamicum. due to the hierarchical nature of the regulatory network, previous transcriptome analyses have not been able to discriminate between direct and indirect targets of σ(h). here, we determined the direct genome-wide targets of σ(h) using chromatin immunoprecipitation with microarray technology (chip-chip) for analysis of a deletion mutant of rsha, encoding an anti ... | 2015 | 25404703 |
| development of a markerless gene replacement system in corynebacterium glutamicum using upp as a counter-selection marker. | corynebacterium glutamicum is well-established for industrial and biotechnological applications. however, its genetic manipulation has generally lagged behind traditional genetic models. in this study, a counter-selectable marker gene upp was firstly confirmed to be more efficient than traditional sacb. furthermore, a markerless gene replacement system was developed by combining upp with double-strand break repair caused by the exogenous endonuclease i-scei. finally, genetic modification using a ... | 2015 | 25376333 |
| promiscuous activity of (s,s)-butanediol dehydrogenase is responsible for glycerol production from 1,3-dihydroxyacetone in corynebacterium glutamicum under oxygen-deprived conditions. | corynebacterium glutamicum can consume glucose to excrete glycerol under oxygen deprivation. although glycerol synthesis from 1,3-dihydroxyacetone (dha) has been speculated, no direct evidence has yet been provided in c. glutamicum. enzymatic and genetic investigations here indicate that the glycerol is largely produced from dha and, unexpectedly, the reaction is catalyzed by (s,s)-butanediol dehydrogenase (buta) that inherently catalyzes the interconversion between s-acetoin and (s,s)-2,3-butan ... | 2015 | 25363556 |
| monitoring the enzyme expression in a respiratory chain of corynebacterium glutamicum in a copper ion-supplemented culture medium. | corynebacterium glutamicum has a branched respiratory chain: one of the branches is cytochrome bcc complex and cytochrome aa3-type cytochrome c oxidase, and the other is cytochrome bd-type menaquinol oxidase. the factors that influence the expression patterns of these respiratory enzymes remain unclear. to investigate the expressional control mechanism of the enzymes, we have previously constructed a promoter assay system utilizing enhanced green fluorescence protein. here, we monitored respirat ... | 2015 | 25338939 |
| the contest for precursors: channelling l-isoleucine synthesis in corynebacterium glutamicum without byproduct formation. | l-isoleucine is an essential amino acid, which is required as a pharma product and feed additive. its synthesis shares initial steps with that of l-lysine and l-threonine, and four enzymes of l-isoleucine synthesis have an enlarged substrate specificity involved also in l-valine and l-leucine synthesis. as a consequence, constructing a strain specifically overproducing l-isoleucine without byproduct formation is a challenge. here, we analyze for consequences of plasmid-encoded genes in corynebac ... | 2015 | 25301583 |
| chassis organism from corynebacterium glutamicum: the way towards biotechnological domestication of corynebacteria. | | 2015 | 25293499 |
| bi-functional cellulases complexes displayed on the cell surface of corynebacterium glutamicum increase hydrolysis of lignocelluloses at elevated temperature. | introducing cellulases into corynebacterium glutamicum leads to the direct degradation of lignocellulosic materials for energy sources. in this study, a cellulase complex containing two cellulolytic enzymes, endoglucanase e (cele) and β-glucosidase a (bgla), was established to completely degrade cellulose to glucose. the cellulases complexes were displayed on the cell surface of c. glutamicum by using the mechanosensitive channel (msc) to anchor enzymes in the cytoplasmic membrane. as confirmed ... | 2014 | 25248702 |
| production of l-glutamic acid with corynebacterium glutamicum (ncim 2168) and pseudomonas reptilivora (ncim 2598): a study on immobilization and reusability. | l-glutamic acid is one of the major amino acids that is present in a wide variety of foods. it is mainly used as a food additive and flavor enhancer in the form of sodium salt. corynebacterium glutamicum (c. glutamicum) is one of the major organisms widely used for glutamic acid production. | 2014 | 25215180 |
| metabolic engineering of corynebacterium glutamicum strain atcc13032 to produce l-methionine. | l-methionine-producing strain qw102/pjyw-4-hom(m) -lysc(m) -brnfe was developed from corynebacterium glutamicum strain atcc13032, using metabolic engineering strategies. these strategies involved (i) deletion of the gene thrb encoding homoserine kinase to increase the precursor supply, (ii) deletion of the gene mcbr encoding the regulator mcbr to release the transcriptional repression to various genes in the l-methionine biosynthetic pathway, (iii) overexpression of the gene lysc(m) encoding fee ... | 2015 | 25196586 |
| idsa is the major geranylgeranyl pyrophosphate synthase involved in carotenogenesis in corynebacterium glutamicum. | corynebacterium glutamicum, a yellow-pigmented soil bacterium that synthesizes the rare cyclic c50 carotenoid decaprenoxanthin and its glucosides, has been engineered for the production of various carotenoids. crte was assumed to be the major geranylgeranyl pyrophosphate (ggpp) synthase in carotenogenesis; however, deletion of crte did not abrogate carotenoid synthesis. in silico analysis of the repertoire of prenyltransferases encoded by the c. glutamicum genome revealed two candidate ggpps gen ... | 2014 | 25181035 |
| metabolic engineering of corynebacterium glutamicum for the production of l-ornithine. | l-ornithine is a non-essential amino acid for various industrial applications in food industry. in this study, corynebacterium glutamicum atcc 13032 was metabolically engineered for the production of l-ornithine. first, the prob and argf genes were deleted to block the competitive branch pathway and to block the conversion of l-ornithine to citrulline, respectively. in addition, the argr gene encoding the regulatory repressor of the l-arginine operon was also deleted. the resulting strain produc ... | 2015 | 25163446 |
| characterization of a corynebacterium glutamicum dnab mutant that shows temperature-sensitive growth and mini-cell formation. | corynebacterium glutamicum is known to perform a unique form of cell division called post-fission snapping division. in order to investigate the mechanism of cell division of this bacterium, we isolated temperature-sensitive mutants from c. glutamicum wild-type strain atcc 31831, and found that one of them, m45, produced high frequencies of mini-cells with no nucleoids. cell pairs composed of an elongated cell, with one nucleoid, connected to a mini-cell, with no nucleoids, were occasionally obs ... | 2014 | 25141796 |
| chassis organism from corynebacterium glutamicum--a top-down approach to identify and delete irrelevant gene clusters. | for synthetic biology applications, a robust structural basis is required, which can be constructed either from scratch or in a top-down approach starting from any existing organism. in this study, we initiated the top-down construction of a chassis organism from corynebacterium glutamicum atcc 13032, aiming for the relevant gene set to maintain its fast growth on defined medium. we evaluated each native gene for its essentiality considering expression levels, phylogenetic conservation, and knoc ... | 2015 | 25139579 |
| co₂ /hco₃⁻ perturbations of simulated large scale gradients in a scale-down device cause fast transcriptional responses in corynebacterium glutamicum. | the exploration of scale-down models to imitate the influence of large scale bioreactor inhomogeneities on cellular metabolism is a topic with increasing relevance. while gradients of substrates, ph, or dissolved oxygen are often investigated, oscillating co2/hco3 (-) levels, a typical scenario in large industrial bioreactors, is rarely addressed. hereby, we investigate the metabolic and transcriptional response in corynebacterium glutamicum wild type as well as the impact on l-lysine production ... | 2014 | 25139448 |
| detoxification of furfural in corynebacterium glutamicum under aerobic and anaerobic conditions. | the toxic fermentation inhibitors in lignocellulosic hydrolysates raise serious problems for the microbial production of fuels and chemicals. furfural is considered to be one of the most toxic compounds among these inhibitors. here, we describe the detoxification of furfural in corynebacterium glutamicum atcc13032 under both aerobic and anaerobic conditions. under aerobic culture conditions, furfuryl alcohol and 2-furoic acid were produced as detoxification products of furfural. the ratio of the ... | 2014 | 25112225 |
| construction of a novel expression system for use in corynebacterium glutamicum. | corynebacterium glutamicum is an important microorganism for production of amino acids in industrial fermentation. suitable vectors are needed for metabolic engineering in c. glutamicum. most available vectors used in c. glutamicum carry antibiotic resistant genes as a genetic labeling for rapid identification of recombinant strains, and antibiotics have to be added to maintain the vector when growing the cells. these vectors, though excellent for laboratory use, are not preferable choices for i ... | 2014 | 25108235 |
| transcriptional response of corynebacterium glutamicum atcc 13032 to hydrogen peroxide stress and characterization of the oxyr regulon. | the aerobic soil bacterium corynebacterium glutamicum atcc 13032 has a remarkable natural resistance to hydrogen peroxide. a major player in hydrogen peroxide defense is the lysr type transcriptional regulator oxyr, homologs of which are present in a wide range of bacteria. in this study, the global transcriptional response of c. glutamicum to oxidative stress induced by hydrogen peroxide was examined using whole genome dna microarrays, demonstrating the dynamic reaction of the regulatory networ ... | 2014 | 25107507 |
| metabolic engineering of corynebacterium glutamicum for l-arginine production. | l-arginine is an important amino acid for diverse industrial and health product applications. here we report the development of metabolically engineered corynebacterium glutamicum atcc 21831 for the production of l-arginine. random mutagenesis is first performed to increase the tolerance of c. glutamicum to l-arginine analogues, followed by systems metabolic engineering for further strain improvement, involving removal of regulatory repressors of arginine operon, optimization of nadph level, dis ... | 2014 | 25091334 |
| oligonucleotide recombination in corynebacteria without the expression of exogenous recombinases. | brevibacterium lactofermentum and corynebacterium glutamicum are important biotechnology species of the genus corynebacterium. the single-strand dna annealing protein (ssap)-independent oligonucleotide-mediated recombination procedure was successfully applied to the commonly used wild-type strains b. lactofermentum aj1511 and c. glutamicum atcc13032. when the rpsl gene was used as a target, the optimized protocol yielded up to (1.4±0.3)×10(3) and (6.7±1.3)×10(3) streptomycin-resistant colonies p ... | 2014 | 25087479 |
| succinate production from co₂-grown microalgal biomass as carbon source using engineered corynebacterium glutamicum through consolidated bioprocessing. | the potential for production of chemicals from microalgal biomass has been considered as an alternative route for co₂ mitigation and establishment of biorefineries. this study presents the development of consolidated bioprocessing for succinate production from microalgal biomass using engineered corynebacterium glutamicum. starch-degrading and succinate-producing c. glutamicum strains produced succinate (0.16 g succinate/g total carbon source) from a mixture of starch and glucose as a model micr ... | 2014 | 25056811 |
| lactate production as representative of the fermentation potential of corynebacterium glutamicum 2262 in a one-step process. | the fermentative properties of thermo-sensitive strain corynebacterium glutamicum 2262 were investigated in processes coupling aerobic cell growth and the anaerobic fermentation phase. in particular, the influence of two modes of fermentation on the production of lactate, the fermentation product model, was studied. in both processes, lactate was produced in significant amount, 27 g/l in batch culture, and up to 55.8 g/l in fed-batch culture, but the specific production rate in the fed-batch cul ... | 2014 | 25036691 |
| genome-wide analysis of the role of global transcriptional regulator gntr1 in corynebacterium glutamicum. | the transcriptional regulator gntr1 downregulates the genes for gluconate catabolism and pentose phosphate pathway in corynebacterium glutamicum. gluconate lowers the dna binding affinity of gntr1, which is probably the mechanism of gluconate-dependent induction of these genes. in addition, gntr1 positively regulates ptsg, a gene encoding a major glucose transporter, and pck, a gene encoding phosphoenolpyruvate carboxykinase. here, we searched for the new target of gntr1 on a genome-wide scale b ... | 2014 | 24982307 |
| rapid assessment of oxygen transfer impact for corynebacterium glutamicum. | oxygen supply is crucial in industrial application of microbial systems, such as corynebacterium glutamicum, but oxygen transfer is often neglected in early strain characterizations, typically done under aerobic conditions. in this work, a new procedure for oxygen transfer screening is presented, assessing the impact of maximum oxygen transfer conditions (otrmax) within microtiter plate-based cultivation for enhanced throughput. oxygen-dependent growth and productivity were characterized for c. ... | 2014 | 24981020 |
| a de novo nadph generation pathway for improving lysine production of corynebacterium glutamicum by rational design of the coenzyme specificity of glyceraldehyde 3-phosphate dehydrogenase. | engineering the cofactor availability is a common strategy of metabolic engineering to improve the production of many industrially important compounds. in this work, a de novo nadph generation pathway is proposed by altering the coenzyme specificity of a native nad-dependent glyceraldehyde 3-phosphate dehydrogenase (gapdh) to nadp, which consequently has the potential to produce additional nadph in the glycolytic pathway. specifically, the coenzyme specificity of gapdh of corynebacterium glutami ... | 2014 | 24953302 |
| artificial oxidative stress-tolerant corynebacterium glutamicum. | we have reported a transcription profile of an adapted corynebacterium glutamicum that showed enhanced oxidative stress resistance. to construct an artificial oxidative stress-resistant strain, gene clusters in the β-ketoadipate pathway, which were up-regulated in the adapted strain, were artificially expressed in the wild-type c. glutamicum. the wild-type strain was unable to grow under 2 mm h2o2 containing minimal medium, while the strains expressing pca gene clusters restored growth under the ... | 2014 | 24949252 |
| rnd transporters protect corynebacterium glutamicum from antibiotics by assembling the outer membrane. | corynebacterium-mycobacterium-nocardia (cmn) group are the causative agents of a broad spectrum of diseases in humans. a distinctive feature of these gram-positive bacteria is the presence of an outer membrane of unique structure and composition. recently, resistance-nodulation-division (rnd) transporters (nicknamed mmpls, mycobacterial membrane protein large) have emerged as major contributors to the biogenesis of the outer membranes in mycobacteria and as promising drug targets. in this study, ... | 2014 | 24942069 |
| transcriptome sequencing revealed the transcriptional organization at ribosome-mediated attenuation sites in corynebacterium glutamicum and identified a novel attenuator involved in aromatic amino acid biosynthesis. | the gram-positive bacterium corynebacterium glutamicum belongs to the order corynebacteriales and is used as a producer of amino acids at industrial scales. due to its economic importance, gene expression and particularly the regulation of amino acid biosynthesis has been investigated extensively. applying the high-resolution technique of transcriptome sequencing (rna-seq), recently a vast amount of data has been generated that was used to comprehensively analyze the c. glutamicum transcriptome. ... | 2014 | 24910972 |
| expanding the laccase-toolbox: a laccase from corynebacterium glutamicum with phenol coupling and cuprous oxidase activity. | laccases are oxidases with potential for application in biotechnology. up to now only fungal laccases have been applied in technical processes, although bacterial laccases are generally easier to handle and more stable at alkaline ph values and elevated temperatures. to increase the toolbox of bacterial laccases and to broaden our knowledge about them, new enzymes have to be characterized. within this study, we describe the new bacterial laccase cgl1 from corynebacterium glutamicum. cgl1 was fou ... | 2014 | 24910971 |
| engineered cytidine triphosphate synthetase with reduced product inhibition. | cytidine triphosphate (ctp) synthetase (ctps) (ec number 6.3.4.2) is a key enzyme involved in de novo synthesis of ctp. it catalyzes the rate-limiting step of the process due to the product inhibition effects on the enzyme. in this study, a novel ctps from corynebacterium glutamicum atcc 13032 (cgctps) was cloned, expressed and characterized. a series of mutagenesis in its n-terminal ammonia ligase (alase) domain was performed in order to reduce ctp product inhibition. all single mutation varian ... | 2014 | 24902851 |
| metabolic engineering corynebacterium glutamicum for the l-lysine production by increasing the flux into l-lysine biosynthetic pathway. | the experiments presented here were based on the conclusions of our previous results. in order to avoid introduction of expression plasmid and to balance the nadh/nad ratio, the nadh biosynthetic enzyme, i.e., nad-dependent glyceraldehyde-3-phosphate dehydrogenase (gadph), was replaced by nadp-dependent gadph, which was used to biosynthesize nadph rather than nadh. the results indicated that the nadh/nad ratio significantly decreased, and glucose consumption and l-lysine production drastically i ... | 2014 | 24879631 |
| corynebacterium glutamicum sdha encoding succinate dehydrogenase subunit a plays a role in cysr-mediated sulfur metabolism. | the corynebacterium glutamicum cysr protein plays a critical regulatory role in sulfur metabolism. in this study, we isolated a protein interacting with cysr by employing a two-hybrid system. subsequent analysis identified the gene as sdha annotated to encode succinate dehydrogenase flavoprotein subunit a, a krebs cycle enzyme. deletion of the gene (δsdha) severely affected cell growth and final cell yield, particularly in complex media. in addition, the δsdha mutant strain was unable to use ace ... | 2014 | 24866946 |
| investigation of ptsg gene in response to xylose utilization in corynebacterium glutamicum. | corynebacterium glutamicum strains nc-2 were able to grow on xylose as sole carbon sources in our previous work. nevertheless, it exhibited the major shortcoming that the xylose consumption was repressed in the presence of glucose. so far, regarding c. glutamicum, there are a number of reports on ptsg gene, the glucose-specific transporter, involved in glucose metabolism. recently, we found ptsg had influence on xylose utilization and investigated the ptsg gene in response to xylose utilization ... | 2014 | 24859809 |
| effect of cofactor folate on the growth of corynebacterium glutamicum syps-062 and l-serine accumulation. | the direct fermentative production of l-serine from sugar has attracted increasing attention. corynebacterium glutamicum syps-062 can directly convert sugar to l-serine. in this study, the effects of exogenous and endogenous regulation of cofactor folate on c. glutamicum syps-062 growth and l-serine accumulation were investigated. for exogenous regulation, the inhibitor (sulfamethoxazole) or precursor (p-aminobenzoate) of folate biosynthesis was added to the medium, respectively. for endogenous ... | 2014 | 24859773 |
| from zero to hero - production of bio-based nylon from renewable resources using engineered corynebacterium glutamicum. | polyamides are important industrial polymers. currently, they are produced exclusively from petrochemical monomers. herein, we report the production of a novel bio-nylon, pa5.10 through an integration of biological and chemical approaches. first, systems metabolic engineering of corynebacterium glutamicum was used to create an effective microbial cell factory for the production of diaminopentane as the polymer building block. in this way, a hyper-producer, with a high diaminopentane yield of 41% ... | 2014 | 24831706 |
| involvement of the global regulator glxr in 3-hydroxybenzoate and gentisate utilization by corynebacterium glutamicum. | corynebacterium glutamicum is an industrially important producer of amino acids and organic acids, as well as an emerging model system for aromatic assimilation. an iclr-type regulator genr has been characterized to activate the transcription of gendfm and genkh operons for 3-hydroxybenzoate and gentisate catabolism and represses its own expression. on the other hand, glxr, a global regulator of the cyclic amp (camp) receptor protein-fumarate nitrate reductase regulator (crp-fnr) type, was also ... | 2014 | 24795375 |
| phosphatase activity of the histidine kinases ensures pathway specificity of the chrsa and hrrsa two-component systems in corynebacterium glutamicum. | the majority of bacterial genomes encode a high number of two-component systems controlling gene expression in response to a variety of different stimuli. the gram-positive soil bacterium corynebacterium glutamicum contains two homologous two-component systems (tcs) involved in the haem-dependent regulation of gene expression. whereas the hrrsa system is crucial for utilization of haem as an alternative iron source, chrsa is required to cope with high toxic haem levels. in this study, we analyse ... | 2014 | 24779520 |
| pupylated proteins in corynebacterium glutamicum revealed by mudpit analysis. | in a manner similar to ubiquitin, the prokaryotic ubiquitin-like protein (pup) has been shown to target proteins for degradation via the proteasome in mycobacteria. however, not all actinobacteria possessing the pup protein also contain a proteasome. in this study, we set out to study pupylation in the proteasome-lacking non-pathogenic model organism corynebacterium glutamicum. a defined pup deletion mutant of c. glutamicum atcc 13032 grew aerobically as the parent strain in standard glucose min ... | 2014 | 24737727 |
| enhancing corynebacterium glutamicum robustness by over-expressing a gene, msha, for mycothiol glycosyltransferase. | over-expression of the gene, msha, coding for mycothiol glycosyl transferase improved the robustness of corynebacterium glutamicum to various stresses. intracellular mycothiol (msh) content was increased by 114 % in wt(pxmj19-msha) compared to wt(pxmj19). survival rates increased by 44, 39, 90, 77, 131, 87, 52, 47, 57, 85 and 33 % as compared to wt(pxmj19) under stress by h2o2 (40 mm), methylglyoxal (5.8 mm), erythromycin (0.08 mg ml(-1)), streptomycin (0.005 mg ml(-1)), cd(2+) (0.01 mm), mn(2+) ... | 2014 | 24737070 |
| double mutation of cell wall proteins cspb and pbp1a increases secretion of the antibody fab fragment from corynebacterium glutamicum. | among other advantages, recombinant antibody-binding fragments (fabs) hold great clinical and commercial potential, owing to their efficient tissue penetration compared to that of full-length iggs. although production of recombinant fab using microbial expression systems has been reported, yields of active fab have not been satisfactory. we recently developed the corynebacterium glutamicum protein expression system (corynex®) and demonstrated improved yield and purity for some applications, alth ... | 2014 | 24731213 |
| the laci-type transcriptional regulator arar acts as an l-arabinose-responsive repressor of l-arabinose utilization genes in corynebacterium glutamicum atcc 31831. | the corynebacterium glutamicum atcc 31831 arabda operon consists of three l-arabinose catabolic genes, upstream of which the galm, arar, and arae genes are located in opposite orientation. arar encodes a laci-type transcriptional regulator that negatively regulates the l-arabinose-inducible expression of arabda and arae (encoding an l-arabinose transporter), through a mechanism that has yet to be identified. here we show that the arar protein binds in vitro to three sites: one upstream of arabda ... | 2014 | 24706742 |
| chorismate-dependent transcriptional regulation of quinate/shikimate utilization genes by lysr-type transcriptional regulator qsur in corynebacterium glutamicum: carbon flow control at metabolic branch point. | the qsu operon of corynebacterium glutamicum comprises four genes (qsuabcd) that underpin the microorganism's quinate/shikimate utilization pathways. the genes encode enzymes that catalyse reactions at the metabolic branch point between the biosynthesis route for synthesis of aromatic compounds and the catabolic route for degradation of quinate and shikimate for energy production. a qsur gene located immediately upstream of qsua encodes a protein (qsur) which activates the operon in the presence ... | 2014 | 24674055 |
| analysis of putative protomer crosstalk in the trimeric transporter betp: the heterotrimer approach. | the homotrimeric, secondary active betaine carrier betp from corynebacterium glutamicum is a model system for stress-regulated transport in bacteria. its activity responds to hyperosmotic stress and it harbors two different functions, transport catalysis (betaine uptake) and stimulus sensing, resp. activity regulation. structural information from 2d and 3d crystals as well as functional analysis of monomerized betp suggested the presence of conformational crosstalk between the individual protome ... | 2014 | 24637177 |
| recent progress in development of synthetic biology platforms and metabolic engineering of corynebacterium glutamicum. | the paradigm of synthetic biology has been evolving, along with relevant engineering, to achieve designed bio-systems. synthetic biology has reached the point where it is possible to develop microbial strains to produce desired chemicals. recent advances in this field have promoted metabolic engineering of corynebacterium glutamicum as an amino-acid producer for use in intelligent microbial-cell factories. here, we review recent advances that address c. glutamicum as a potential model organism f ... | 2014 | 24632177 |
| a method for gene amplification and simultaneous deletion in corynebacterium glutamicum genome without any genetic markers. | a method for the simultaneous replacement of a given gene by a target gene, leaving no genetic markers, has been developed. the method is based on insertional inactivation and double-crossover homologous recombination. with this method, the lysc(t311i), fbp and ddh genes were inserted into corynebacterium glutamicum genome, and the pck, alat and avta genes were deleted. mobilizable plasmids with lysc(t311i), fbp and ddh cassettes and two homologous arms on the ends of pck, alat and avta were con ... | 2014 | 24613758 |
| carbon flux analysis by 13c nuclear magnetic resonance to determine the effect of co2 on anaerobic succinate production by corynebacterium glutamicum. | wild-type corynebacterium glutamicum produces a mixture of lactic, succinic, and acetic acids from glucose under oxygen deprivation. we investigated the effect of co2 on the production of organic acids in a two-stage process: cells were grown aerobically in glucose, and subsequently, organic acid production by nongrowing cells was studied under anaerobic conditions. the presence of co2 caused up to a 3-fold increase in the succinate yield (1 mol per mol of glucose) and about 2-fold increase in a ... | 2014 | 24610842 |
| the physiological role of riboflavin transporter and involvement of fmn-riboswitch in its gene expression in corynebacterium glutamicum. | riboflavin is a precursor of flavin mononucleotide (fmn) and flavin adenine dinucleotide (fad), which work as cofactors of numerous enzymes. understanding the supply system of these cofactors in bacteria, particularly those used for industrial production of value added chemicals, is important given the pivotal role the cofactors play in substrate metabolism. in this work, we examined the effect of disruption of riboflavin utilization genes on cell growth, cytoplasmic flavin levels, and expressio ... | 2014 | 24531272 |
| construction and application of novel feedback-resistant 3-deoxy-d-arabino-heptulosonate-7-phosphate synthases by engineering the n-terminal domain for l-phenylalanine synthesis. | 3-deoxy-d-arabino-heptulosonate 7-phosphate synthase (dahp synthase) encoded by arof is the first enzyme of the shikimate pathway. in the present study, an arof variant with a deficiency in residue ile11 (named arof*) was shown to be insensitive to l-tyrosine. according to three-dimensional structure analysis, nine arof variants were constructed with truncation of different n-terminal fragments, and overexpression of the variants arof(δ(1-9)) , arof(δ(1-10)) , arof(δ(1-12)) and, in particular, a ... | 2014 | 24517515 |
| high-throughput screening of a corynebacterium glutamicum mutant library on genomic and metabolic level. | due to impressive achievements in genomic research, the number of genome sequences has risen quickly, followed by an increasing number of genes with unknown or hypothetical function. this strongly calls for development of high-throughput methods in the fields of transcriptomics, proteomics and metabolomics. of these platforms, metabolic profiling has the strongest correlation with the phenotype. we previously published a high-throughput metabolic profiling method for c. glutamicum as well as the ... | 2014 | 24504095 |
| the pyruvate dehydrogenase complex of corynebacterium glutamicum: an attractive target for metabolic engineering. | the pyruvate dehydrogenase complex (pdhc) catalyzes the oxidative thiamine pyrophosphate-dependent decarboxylation of pyruvate to acetyl-coa and co2. since pyruvate is a key metabolite of the central metabolism and also the precursor for several relevant biotechnological products, metabolic engineering of this multienzyme complex is a promising strategy to improve microbial production processes. this review summarizes the current knowledge and achievements on metabolic engineering approaches to ... | 2014 | 24486441 |
| genetic characterization of 4-cresol catabolism in corynebacterium glutamicum. | corynebacterium glutamicum uses 4-cresol as sole carbon source for growth. protocatechuate 3,4-dioxygenase activity had been detected when c. glutamicum was grown with 4-cresol. in this work, we found that 4-cresol was catabolized via 4-hydroxybenzoate and protocatechuate as intermediate metabolites, and a genetic cluster called cre (designated for 4-cresol, creabcdefghir, tagged as ncgl0521-ncgl0531 in ncbi) was identified. the cre gene cluster comprises of 11 genes, and six of them were experi ... | 2014 | 24480572 |
| application of a genetically encoded biosensor for live cell imaging of l-valine production in pyruvate dehydrogenase complex-deficient corynebacterium glutamicum strains. | the majority of biotechnologically relevant metabolites do not impart a conspicuous phenotype to the producing cell. consequently, the analysis of microbial metabolite production is still dominated by bulk techniques, which may obscure significant variation at the single-cell level. in this study, we have applied the recently developed lrp-biosensor for monitoring of amino acid production in single cells of gradually engineered l-valine producing corynebacterium glutamicum strains based on the p ... | 2014 | 24465669 |
| lysine overproducing corynebacterium glutamicum is characterized by a robust linear combination of two optimal phenotypic states. | a homoserine auxotroph strain of corynebacterium glutamicum accumulates storage compound trehalose with lysine when limited by growth. industrially lysine is produced from c. glutamicum through aspartate biosynthetic pathway, where enzymatic activity of aspartate kinase is allosterically controlled by the concerted feedback inhibition of threonine plus lysine. ample threonine in the medium supports growth and inhibits lysine production (phenotype-i) and its complete absence leads to inhibition o ... | 2013 | 24432142 |
| process inhomogeneity leads to rapid side product turnover in cultivation of corynebacterium glutamicum. | corynebacterium glutamicum has large scale industrial applications in the production of amino acids and the potential to serve as a platform organism for new products. this means the demand for industrial process development is likely to increase. however, large scale cultivation conditions differ from laboratory bioreactors, mostly due to the formation of concentration gradients at the industrial scale. this leads to an oscillating supply of oxygen and nutrients for microorganisms with uncertai ... | 2014 | 24410842 |
| identification of low-molecular-weight compounds inhibiting growth of corynebacteria: potential lead compounds for antibiotics. | the bacterial genus corynebacteria contains several pathogenic species that cause diseases such as diphtheria in humans and "cheesy gland" in goats and sheep. thus, identifying new therapeutic targets to treat corynebacteria infections is both medically and economically important. cg2496, a functionally uncharacterized protein from corynebacterium glutamicum, was evaluated using an nmr ligand-affinity screen. a total of 11 compounds from a library of 460 biologically active compounds were shown ... | 2014 | 24403054 |
| next-generation sequencing-based transcriptome analysis of l-lysine-producing corynebacterium glutamicum atcc 21300 strain. | in the present study, 151 genes showed a significant change in their expression levels in corynebacterium glutamicum atcc 21300 compared with those of c. glutamicum atcc 13032. of these 151 genes, 56 genes (2%) were up-regulated and 95 genes (3%) were down-regulated. rna sequencing analysis also revealed that 11 genes, involved in the l-lysine biosynthetic pathway of c. glutamicum, were up- or down-regulated compared with those of c. glutamicum atcc 13032. of the 151 genes, 10 genes were identif ... | 2013 | 24385368 |
| stimulus analysis of betp activation under in vivo conditions. | the secondary active, na(+) coupled glycine betaine carrier betp from corynebacterium glutamicum betp was shown to harbor two different functions, transport catalysis (betaine uptake) and stimulus sensing, as well as activity regulation in response to hyperosmotic stress. by analysis in a reconstituted system, the rise in the cytoplasmic k(+) concentration was identified as a primary stimulus for betp activation. we have now studied regulation of betp in vivo by independent variation of both the ... | 2014 | 24384063 |
| nrdh redoxin enhances resistance to multiple oxidative stresses by acting as a peroxidase cofactor in corynebacterium glutamicum. | nrdh redoxins are small protein disulfide oxidoreductases behaving like thioredoxins but sharing a high amino acid sequence similarity to glutaredoxins. although nrdh redoxins are supposed to be another candidate in the antioxidant system, their physiological roles in oxidative stress remain unclear. in this study, we confirmed that the corynebacterium glutamicum nrdh redoxin catalytically reduces the disulfides in the class ib ribonucleotide reductases (rnr), insulin and 5,5'-dithiobis-(2-nitro ... | 2014 | 24375145 |
| reducing lactate secretion by ldha deletion in l-glutamate- producing strain corynebacterium glutamicum gdk-9. | l-lactate is one of main byproducts excreted in to the fermentation medium. to improve l-glutamate production and reduce l-lactate accumulation, l-lactate dehydrogenase-encoding gene ldha was knocked out from l-glutamate producing strain corynebacterium glutamicum gdk-9, designated gdk-9δldha. gdk-9δldha produced approximately 10.1% more l-glutamate than the gdk-9, and yielded lower levels of such by-products as α-ketoglutarate, l-lactate and l-alanine. since dissolved oxygen (do) is one of main ... | 2014 | 25763057 |
| rational design of allosteric regulation of homoserine dehydrogenase by a nonnatural inhibitor l-lysine. | allosteric proteins, which can sense different signals, are interesting biological parts for synthetic biology. in particular, the design of an artificial allosteric enzyme to sense an unnatural signal is both challenging and highly desired, for example, for a precise and dynamical control of fluxes of growth-essential but byproduct pathways in metabolic engineering of industrial microorganisms. in this work, we used homoserine dehydrogenase (hsdh) of corynebacterium glutamicum, which is natural ... | 2015 | 24344690 |
| microfluidic picoliter bioreactor for microbial single-cell analysis: fabrication, system setup, and operation. | in this protocol the fabrication, experimental setup and basic operation of the recently introduced microfluidic picoliter bioreactor (plbr) is described in detail. the plbr can be utilized for the analysis of single bacteria and microcolonies to investigate biotechnological and microbiological related questions concerning, e.g. cell growth, morphology, stress response, and metabolite or protein production on single-cell level. the device features continuous media flow enabling constant environm ... | 2013 | 24336165 |
| deregulation of feedback inhibition of phosphoenolpyruvate carboxylase for improved lysine production in corynebacterium glutamicum. | allosteric regulation of phosphoenolpyruvate carboxylase (pepc) controls the metabolic flux distribution of anaplerotic pathways. in this study, the feedback inhibition of corynebacterium glutamicum pepc was rationally deregulated, and its effect on metabolic flux redistribution was evaluated. based on rational protein design, six pepc mutants were designed, and all of them showed significantly reduced sensitivity toward aspartate and malate inhibition. introducing one of the point mutations (n9 ... | 2014 | 24334667 |
| pushing product formation to its limit: metabolic engineering of corynebacterium glutamicum for l-leucine overproduction. | using metabolic engineering, an efficient l-leucine production strain of corynebacterium glutamicum was developed. in the wild type of c. glutamicum, the leua-encoded 2-isopropylmalate synthase (ipms) is inhibited by low l-leucine concentrations with a k(i) of 0.4 mm. we identified a feedback-resistant imps variant, which carries two amino acid exchanges (r529h, g532d). the corresponding leua(fbr) gene devoid of the attenuator region and under control of a strong promoter was integrated in one, ... | 2014 | 24333966 |
| increase in lactate yield by growing corynebacterium glutamicum in a bioelectrochemical reactor. | under conditions conductive to growth, corynebacterium glutamicum showed higher lactate yield from glucose (1.62 ± 0.04) in a bioelectrochemical reactor including 0.2 mm of anthraquinone 2,6-disulfonate with the electrode potential regulated at -0.6 v (vs. ag/agcl) than in a non-regulated environment (1.10 ± 0.03), clarifying that low cathodic potential is beneficial for lactate production. | 2014 | 24315531 |
| exploring signal transduction in heteromultimeric protein based on energy dissipation model. | dynamic intersubunit interactions are key elements in the regulation of many biological systems. a better understanding of how subunits interact with each other and how their interactions are related to dynamic protein structure is a fundamental task in biology. in this paper, a heteromultimeric allosteric protein, corynebacterium glutamicum aspartokinase, is used as a model system to explore the signal transduction involved in intersubunit interactions and allosteric communication with an empha ... | 2015 | 24279729 |
| role of flavohaemoprotein hmp and nitrate reductase narghji of corynebacterium glutamicum for coping with nitrite and nitrosative stress. | the influence of nitrate and nitrite on growth of corynebacterium glutamicum under aerobic conditions in shake flasks was analysed. when dissolved oxygen became limiting at higher cell densities, nitrate was reduced almost stoichiometrically to nitrite by nitrate reductase (narghji). the nitrite concentration also declined slowly, presumably as a result of several reactions including reduction to nitric oxide by a side-activity of nitrate reductase. the flavohaemoglobin gene hmp was most strongl ... | 2014 | 24237595 |
| assessment of robustness against dissolved oxygen/substrate oscillations for c. glutamicum dm1933 in two-compartment bioreactor. | corynebacterium glutamicum is an important organism for industrial biotechnology; particularly, in amino acid production (e.g. l-lysine). production scales often reach reactor working volumes of several hundred cubic meters, which triggers inhomogeneous distribution of substrates and dissolved gasses due to increasing mixing times. individual cells which follow the flow profile through the reactor are experiencing oscillating microenvironments. oscillations can have an influence on the process p ... | 2014 | 24218302 |
| metabolic engineering of corynebacterium glutamicum for 2-ketoisocaproate production. | 2-ketoisocaproate (kic) is used as a therapeutic agent, and a kic-producing organism may serve as a platform for products deriving from this 2-keto acid. we engineered corynebacterium glutamicum for the production of kic from glucose by deletion of ltbr and ilve, encoding the transcriptional repressor ltbr and transaminase b, respectively, and additional overexpression of ilvbncd, encoding acetohydroxyacid synthase, acetohydroxyacid isomeroreductase, and dihydroxyacid dehydratase. the kic-produc ... | 2014 | 24169948 |
| analysis of sos-induced spontaneous prophage induction in corynebacterium glutamicum at the single-cell level. | the genome of the gram-positive soil bacterium corynebacterium glutamicum atcc 13032 contains three integrated prophage elements (cgp1 to -3). recently, it was shown that the large lysogenic prophage cgp3 (∼187 kbp) is excised spontaneously in a small number of cells. in this study, we provide evidence that a spontaneously induced sos response is partly responsible for the observed spontaneous cgp3 induction. whereas previous studies focused mainly on the induction of prophages at the population ... | 2014 | 24163339 |
| elucidation of the regulation of ethanol catabolic genes and ptsg using a glxr and adenylate cyclase gene (cyab) deletion mutants of corynebacterium glutamicum atcc 13032. | the cyclic amp receptor protein (crp) homolog, glxr, controls the expression of several genes involved in the regulation of diverse physiological processes in corynebacterium glutamicum. in silico analysis has revealed the presence of glxr binding sites upstream of genes adha, ald, and ptsg, encoding glucose-specific phosphotransferase system protein, alcohol dehydrogenase (adh), and acetaldehyde dehydrogenase (aldh), respectively. however, the involvement of the glxr-camp complex on the express ... | 2013 | 24150494 |
| corynebacterium glutamicum arnr controls expression of nitrate reductase operon narkghji and nitric oxide (no)-detoxifying enzyme gene hmp in an no-responsive manner. | corynebacterium glutamicum arnr is a novel transcriptional regulator that represses expression of the nitrate reductase operon narkghji and the nitric oxide (no)-detoxifying flavohemoglobin gene hmp under aerobic conditions. in a previous study, we showed that arnr-mediated repression is relieved during anaerobic nitrate respiration, but we could not pinpoint the specific signal that arnr senses. in this study, we show that in the absence of nitrate, arnr-mediated repression is maintained under ... | 2014 | 24142248 |
| impact of different co2/hco3- levels on metabolism and regulation in corynebacterium glutamicum. | we investigated the growth kinetics and transcriptional responses of corynebacterium glutamicum in environments with low (pco2<40 mbar) and high (pco2 ≥ 300 mbar) co2/hco3(-) levels compared to standard conditions. when cultivated at high co2/hco3(-)-levels, c. glutamicum showed increased (63%) biomass to substrate yields during the initial growth phase. other kinetic parameters such as growth rate (μ), specific glucose consumption rate (qs), and selected enzymatic activities of anaplerotic reac ... | 2013 | 24140290 |
| improved succinate production in corynebacterium glutamicum by engineering glyoxylate pathway and succinate export system. | a dual route for anaerobic succinate production was engineered into corynebacterium glutamicum. the glyoxylate pathway was reconstructed by overexpressing isocitrate lyase, malate synthase and citrate synthase. the engineered strain produced succinate with a yield of 1.34 mol (mol glucose)(-1). further overexpression of succinate exporter, suce, increased succinate yield to 1.43 mol (mol glucose)(-1). metabolic flux analysis revealed that the glyoxylate pathway was further activated by engineeri ... | 2014 | 24129953 |
| a structural and dynamic investigation of the inhibition of catalase by nitric oxide. | determining the chemical and structural modifications occurring within a protein during fundamental processes such as ligand or substrate binding is essential to building up a complete picture of biological function. currently, significant unanswered questions relate to the way in which protein structural dynamics fit within the structure-function relationship and to the functional role, if any, of bound water molecules in the active site. addressing these questions requires a multidisciplinary ... | 2013 | 24121528 |
| current knowledge on mycolic acids in corynebacterium glutamicum and their relevance for biotechnological processes. | corynebacterium glutamicum is the world's largest producer of glutamate and lysine. industrial glutamate overproduction is induced by empirical processes, such as biotin limitation, supplementation with specific surfactants or addition of sublethal concentration of certain antibiotics to the culture media. although gram-positive bacteria, c. glutamicum and related bacterial species and genera contain, in addition to the plasma membrane, an outer permeability membrane similar to that of gram-nega ... | 2013 | 24113823 |
| nmr localization of the o-mycoloylation on porh, a channel forming peptide from corynebacterium glutamicum. | porh and pora are two small peptides that, in complex, form a voltage-dependent ion channel in the outer membrane of corynebacterium glutamicum. specific post-translational modifications on pora and porh are required for the formation of a functional ion channel. the assignment of porh proton nmr chemical shifts in dmso, allowed identifying unambiguously the exact position of the porh o-mycoloylation on ser 56 side chain. this was further confirmed by site directed mutagenesis and mass spectrome ... | 2013 | 24100136 |
| functional analysis of tetr-family regulator amtrsav in streptomyces avermitilis. | in actinomycetes, two main regulators, the ompr-like glnr and the tetr-type amtr, have been identified as the central regulators for nitrogen metabolism. glnr-mediated regulation was previously identified in different actinomycetes except for members of the genus corynebacterium, in which amtr plays a predominant role in nitrogen metabolism. interestingly, some actinomycetes (e.g. streptomyces avermitilis) harbour both glnr- and amtr-homologous genes in the chromosome. thus, it will be interesti ... | 2013 | 24068239 |
| improvement of cell growth and l-lysine production by genetically modified corynebacterium glutamicum during growth on molasses. | fructose-1,6-bisphosphatase (fbpase) and fructokinase (scrk) have important roles in regenerating glucose-6-phosphate in the pentose phosphate pathway (ppp), and thus increasing l-lysine production. this article focuses on the development of l-lysine high-producing strains by heterologous expression of fbpase gene fbp and scrk gene scrk in c. glutamicum lysc (fbr) with molasses as the sole carbon source. heterologous expression of fbp and scrk lead to a decrease of residual sugar in fermentation ... | 2013 | 24029876 |
| beyond growth rate 0.6: what drives corynebacterium glutamicum to higher growth rates in defined medium. | in a former study we showed that corynebacterium glutamicum grows much faster in defined cgxii glucose medium when growth was initiated in highly diluted environments [grünberger et al. (2013b) biotechnol bioeng]. here we studied the batch growth of c. glutamicum in cgxii at a comparable low starting biomass concentration of od ≈ 0.005 in more detail. during bioreactor cultivations a bi-phasic growth behavior with changing growth rates was observed. initially the culture grew with μˆ=0.61±0.02 h ... | 2014 | 23996851 |
| development of fatty acid-producing corynebacterium glutamicum strains. | to date, no information has been made available on the genetic traits that lead to increased carbon flow into the fatty acid biosynthetic pathway of corynebacterium glutamicum. to develop basic technologies for engineering, we employed an approach that begins by isolating a fatty acid-secreting mutant without depending on mutagenic treatment. this was followed by genome analysis to characterize its genetic background. the selection of spontaneous mutants resistant to the palmitic acid ester surf ... | 2013 | 23995924 |
| visualization of imbalances in sulfur assimilation and synthesis of sulfur-containing amino acids at the single-cell level. | we describe genetically encoded sensors which transmit elevated cytosolic concentrations of o-acetyl serine (oas) and o-acetyl homoserine (oah)-intermediates of l-cysteine and l-methionine synthesis-into an optical output. the sensor psenoas3 elicits 7.5-fold-increased fluorescence in cultures of a corynebacterium glutamicum strain that excrete l-cysteine. determination of the cytosolic oas concentration revealed an increase to 0.13 mm, whereas the concentration in the reference strain was below ... | 2013 | 23995919 |
| effect of biotin on transcription levels of key enzymes and glutamate efflux in glutamate fermentation by corynebacterium glutamicum. | biotin is an important factor affecting the performance of glutamate fermentation by biotin auxotrophic corynebacterium glutamicum and glutamate is over-produced only when initial biotin content is controlled at suitable levels or initial biotin is excessive but with tween 40 addition during fermentation. the transcription levels of key enzymes at pyruvate, isocitrate and α-ketoglutarate metabolic nodes, as well as transport protein (tp) of glutamate were investigated under the conditions of var ... | 2014 | 23990041 |
| enzyme-substrate complexes of the quinate/shikimate dehydrogenase from corynebacterium glutamicum enable new insights in substrate and cofactor binding, specificity, and discrimination. | quinate dehydrogenase (qdh) catalyzes the reversible oxidation of quinate to 3-dehydroquinate by nicotineamide adenine dinucleotide (nadh) and is involved in the catabolic quinate metabolism required for the degradation of lignin. the enzyme is a member of the family of shikimate/quinate dehydrogenases (sdh/qdh) occurring in bacteria and plants. we characterized the dual-substrate quinate/shikimate dehydrogenase (qsdh) from corynebacterium glutamicum (cglqsdh) kinetically and revealed a clear su ... | 2013 | 23929881 |
| construction of a prophage-free variant of corynebacterium glutamicum atcc 13032 for use as a platform strain for basic research and industrial biotechnology. | the activity of bacteriophages and phage-related mobile elements is a major source for genome rearrangements and genetic instability of their bacterial hosts. the genome of the industrial amino acid producer corynebacterium glutamicum atcc 13032 contains three prophages (cgp1, cgp2, and cgp3) of so far unknown functionality. several phage genes are regularly expressed, and the large prophage cgp3 (∼190 kbp) has recently been shown to be induced under certain stress conditions. here, we present t ... | 2013 | 23892752 |
| protein s-mycothiolation functions as redox-switch and thiol protection mechanism in corynebacterium glutamicum under hypochlorite stress. | protein s-bacillithiolation was recently discovered as important thiol protection and redox-switch mechanism in response to hypochlorite stress in firmicutes bacteria. here we used transcriptomics to analyze the naocl stress response in the mycothiol (msh)-producing corynebacterium glutamicum. we further applied thiol-redox proteomics and mass spectrometry (ms) to identify protein s-mycothiolation. | 2014 | 23886307 |
| a role of the transcriptional regulator lldr (ncgl2814) in glutamate metabolism under biotin-limited conditions in corynebacterium glutamicum. | corynebacterium glutamicum is a gram-positive, rod-shaped, aerobic bacterium used for the fermentative production of l-glutamate. lldr (ncgl2814) is known as a repressor for ldha and lldd encoding lactate dehydrogenases. ldha is responsible for production of l-lactate, while lldd is for its assimilation. since l-lactate production was observed as a by-product of glutamate production under biotin-limited conditions, lldr might play a regulatory role in the glutamate metabolism. here for the first ... | 2013 | 23863291 |
| platform engineering of corynebacterium glutamicum with reduced pyruvate dehydrogenase complex activity for improved production of l-lysine, l-valine, and 2-ketoisovalerate. | exchange of the native corynebacterium glutamicum promoter of the acee gene, encoding the e1p subunit of the pyruvate dehydrogenase complex (pdhc), with mutated dapa promoter variants led to a series of c. glutamicum strains with gradually reduced growth rates and pdhc activities. upon overexpression of the l-valine biosynthetic genes ilvbnce, all strains produced l-valine. among these strains, c. glutamicum acee a16 (pjc4 ilvbnce) showed the highest biomass and product yields, and thus it was f ... | 2013 | 23835179 |
| taking control over control: use of product sensing in single cells to remove flux control at key enzymes in biosynthesis pathways. | enzymes initiating the biosynthesis of cellular building blocks are frequently inhibited by the end-product of the respective pathway. here we present an approach to rapidly generate sets of enzymes overriding this control. it is based on the in vivo detection of the desired end-product in single cells using a genetically encoded sensor. the sensor transmits intracellular product concentrations into a graded optical output, thus enabling ultrahigh-throughput screens by facs. we randomly mutageni ... | 2014 | 23829416 |
| modeling and optimization of glutamic acid production using mixed culture of corynebacterium glutamicum ncim2168 and pseudomonas reptilivora ncim2598. | in this study, a hybrid system of response surface methodology followed by genetic algorithm has been adopted to optimize the production medium for l-glutamic acid fermentation with mixed cultures of corynebacterium glutamicum and pseudomonas reptilovora. the optimal combination of media components for maximal production of l-glutamic acid was found to be 49.99 g l(-1) of glucose, 10 g l(-1) of urea, 18.06% (v/v) of salt solution, and 4.99% (v/v) of inoculum size. the experimental glutamic acid ... | 2013 | 23768112 |