Corynebacterium glutamicum
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PROVIDER: PRJNA322319 | ENA |
REPOSITORIES: ENA
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Project description:Gamma-aminobutyric acid (GABA) is a non-protein amino acid widespread in Nature. Among the various uses of GABA, its lactam form 2-pyrrolidone can be chemically converted to the biodegradable plastic polyamide-4. In metabolism, GABA can be synthesized either by decarboxylation of L-glutamate or by a pathway that starts with the transamination of putrescine. Fermentative production of GABA from glucose by recombinant Corynebacterium glutamicum has been described via both routes. Putrescine-based GABA production was characterized by accumulation of by-products such as N-acetyl-putrescine. Their formation was abolished by deletion of the spermi(di)ne N-acetyl-transferase gene snaA. To improve provision of L-glutamate as precursor 2-oxoglutarate dehydrogenase activity was reduced by changing the translational start codon of the chromosomal gene for 2-oxoglutarate dehydrogenase subunit E1o to the less preferred TTG and by maintaining the inhibitory protein OdhI in its inhibitory formby changing amino acid residue 15 from threonine to alanine. Putrescine-based GABA production by the strains described here led to GABA titers up to 63.2 g L-1 in fed-batch cultivation at maximum volumetric productivities up to 1.34 g L-11 h1-1, the highest volumetric productivity for fermentative GABA production reported to date. Moreover, GABA production from the carbon sources xylose, glucosamine, and N-acetyl-glucosamine that do not have competing uses in the food or feed industries was established.
2016-05-21 | GSE81695 | GEO
Project description:The dicarboxylic acid glutarate is gaining attention in the chemical and pharmaceutical industry as promising building-block. Synthesis of glutarate via microbial fermentation is a desirable aim which will allow the production of biopolymers avoiding fossil raw materials. Here, by rational metabolic engineering of the biofactory microorganism Corynebacterium glutamicum the fermentative production of glutarate from glucose was established. Modifications focused on increase glucose consumption and reduce by-products formation together with the heterologous overexpression of the L-lysine decarboxylase, putrescine transaminase and putrescine dehydrogenase genes from E. coli in the L-lysine producer GRLys1 allowed production the glutarate precursor 5-aminovalerate. Additional heterologous overexpression of 5-aminovalerate amino transferase and glutarate-semialdehyde dehydrogenase genes from C. glutamicum and three Pseudomonas species enabled glutarate synthesis from glucose. By coupling glutarate production with the glutamate synthesis of C. glutamicum glutarate titer improved 10%. The final strain was tested in a glucose-based fed-batch fermentation
2018-11-20 | GSE117175 | GEO
Project description:Corynebacterium glutamicum shows a great potential for the production of gamma-aminobutyric acid (GABA) from glucose fermentation via putrescine. GABA, a non-protein amino acid widespread in nature, is a component of pharmaceuticals, foods and the biodegradable plastic polyamide 4. Here, the effect of GABA in the growth of C. glutamicum was evaluated. It was estimated that the presence 1.1 M of GABA in the medium reduces the maximum growth rate of C. glutamicum to half. It was also shown that the presence of GABA in the medium negatively affects the growth of C. glutamicum in ethanol as sole carbon source. Furthermore, a new route for the production of GABA in C. glutamicum was established. GABA production from glucose fermentation via putrescine was achieved by plasmid-based overexpression of putrescine transaminase (PatA) and gamma-aminobutyraldehyde dehydrogenase (PatD) in a putrescine production strain. The resultant strain can produce 5.3 ± 0.1 g L-1 of GABA. GABA production was improved by avoiding the formation of N-acetylputrescine and by reducing the amount of nitrogen in CGXII medium. Deletion of the genes responsible for GABA catabolism and GABA re-uptake led to an increase in the GABA production of 21% achieving a titer 8.0 ± 0.3 g L-1 and an increase in the volumetric productivity of 41% reaching a productivity of 0.31 g L-1 h-1, the highest volumetric productivity achieved so far for GABA production in C. glutamicum from glucose fermentation in flasks fermentations. The results obtained hitherto are very promising and competitive compared to the traditional pathway for the production of GABA.
2015-10-22 | GSE74258 | GEO
Project description:A new metabolic route for the production of gamma-aminobutyric acid in Corynebacterium glutamicum
| PRJNA299574 | ENA
Project description:Purpose: The ability to rationally manipulate the transcriptional states of cells would be of great use in medicine and bioengineering. We have developed a novel algorithm, NetSurgeon, which utilizes genome-wide gene regulatory networks to identify interventions that force a cell toward a desired expression state. Results: We used NetSurgeon to select transcription factor deletions aimed at improving ethanol production in S. cerevisiae cultures that are catabolizing xylose. We reasoned that interventions that move the transcriptional states of cells utilizing xylose toward the fermentative state typical of cells that are producing ethanol rapidly (while utilizing glucose) might improve xylose fermentation. Some of the interventions selected by NetSurgeon successfully promoted a fermentative transcriptional state in the absence of glucose, resulting in strains with a 2.7-fold increase in xylose import rates, a 4-fold improvement in xylose integration into central carbon metabolism, or a 1.3-fold increase in ethanol production rate. Conclusions: We conclude by presenting an integrated model of transcriptional regulation and metabolic flux that will enable future metabolic engineering efforts aimed at improving xylose fermentation to prioritize functional regulators of central carbon metabolism.
2016-06-03 | GSE69682 | GEO
Project description:D-glucose, D-xylose and L-arabinose are three major monosaccharides in the plant cell wall. Complete utilization of all three sugars is still a bottleneck for second-generation cellulolytic bioethanol production, especially for L-arabinose. However, little is known about the gene expression profiles during L-arabinose utilization in fungi at genome-wide level and a comparison of the genome-wide fungal response to these three major monosaccharides has not yet been reported. To better understand the microbial response and utilization of L-arabinose for subsequent microbial engineering for co-fermentation all three sugars, we performed transcriptome analysis of N. crassa grown on L-arabinose, compared with that on D-xylose and D-glucose. RNA was extracted from cultures of N. carassa in early growth stage growing with D-glucose, L-arabinose or D-xylose as carbon source; duplicate cultures were sampled in some conditions.
2014-03-17 | E-GEOD-51091 | biostudies-arrayexpress
Project description:D-glucose, D-xylose and L-arabinose are three major monosaccharides in the plant cell wall. Complete utilization of all three sugars is still a bottleneck for second-generation cellulolytic bioethanol production, especially for L-arabinose. However, little is known about the gene expression profiles during L-arabinose utilization in fungi at genome-wide level and a comparison of the genome-wide fungal response to these three major monosaccharides has not yet been reported. To better understand the microbial response and utilization of L-arabinose for subsequent microbial engineering for co-fermentation all three sugars, we performed transcriptome analysis of N. crassa grown on L-arabinose, compared with that on D-xylose and D-glucose.
2014-03-17 | GSE51091 | GEO
Project description:Pleurotus ostreatus, an edible white-rot fungus of great commercial and nutritional value, grows by metabolizing mainly glucose and xylose, the two major sugars in lignocellulosic biomass. In this study, a comparative proteomic analysis of P. ostreatus grown in submerged fermentation on medium with glucose, xylose and mixtures of them as carbon sources was conducted. In the same conditions, the metabolic response of the fungus was evaluated in the production of the main nutritional components of the fungus such as proteins, lipids, intracellular and extracellular polysaccharides. Xylose is found to up-regulate the tricarboxylic acid cycle whereas glucose upregulates the glycolysis cycle. An analysis of the upregulated proteins through the STRING database revealed that xylose upregulates mostly proteins related to amino acid biosynthesis. Leucine, Valine and Isoleucine biosynthesis pathways were found to be the most triggered pathway. These findings provide new insights into the proteomic and metabolic response of the fungus to the major sugars of lignocellulosic biomass. Based on these results, the metabolism of P. ostreatus could be turned towards a specific biological process using a suitable substrate. In addition, from proteomic analysis, strategies for genetic engineering of the strain could be adopted aiming to enhance protein expression, secretion and biotechnological-related pathways of the strain, a very constructive tool for the food industry.
2024-11-19 | PXD049213 | Pride
Project description:Efficient assimilation of renewable feedstocks is the cornerstone for achieving sustainable and economical microbial production of commodity chemicals. Unfortunately, most renewables are foreign to the cellular metabolism of classical industrial workhorses, resulting in unsatisfactory biomanufacturing performance. Here, Corynebacterium glutamicum was systematically engineered for rapid non-natural xylose metabolism and the underlying adaptations were elucidated by combining metabolic engineering, adaptive laboratory evolution and systems biology techniques. A plasmid-free, stable and efficient xylose-utilizing chassis strain, named CGS15, was reconstructed with both a rapid specific growth rate of 0.341 h-1 on xylose and an excellent co-utilization of glucose and xylose at a ratio of about 2:1. For the first time, we revealed a novel xylose regulatory mechanism by the endogenous transcription factor IpsA with global regulatory effects on C. glutamicum core carbon and energy metabolism. The coordination between the heterologous xylose metabolism and the endogenous carbon/energy metabolism both endowed cells with accelerated growth and released carbon catabolite repression. Finally, this chassis demonstrated great promise for lignocellulosic biorefinery applications by producing 97.1 g/L of the platform compound succinate from corn stalk hydrolysate with an average productivity of 8.09 g/L/h. This work provides an elegant paradigm to understand and engineer the metabolism of renewable substrates for sustainable biomanufacturing.
2022-10-03 | GSE184402 | GEO
Project description:Background: Lignocellulosic biomass is a promising renewable feedstock for the microbial production of fuels. To release the major fermentable sugars such as glucose and xylose, pretreatment and enzymatic hydrolysis of biomass feedstock are needed. During this process, many toxic compounds are produced or introduced which subsequently inhibit microbial growth and eventually the production rate and yield. Acetate is one of the major inhibitors liberated from hemicelluloses during dilute acid pretreatment. An understanding of the toxic effects of acetate on the fermentation microorganism is critical to improving biofuel yields in the process. In addition, the efficient utilization of mixed sugars of glucose and xylose in the presence of hydrolysate inhibitors is crucial for economic biofuel production. Results: We have observed previously that some pretreatment inhibitors affect growth and performance in Zymomonas mobilis 8b differently when different sugars (e.g. glucose or xylose) are used as substrate. To investigate this phenomenon at the cellular level, microarray technology was used to investigate the acetate stress responses of Z. mobilis 8b when using single carbon sources of glucose or xylose, and mixed sugars of glucose and xylose. We designed a microarray based on the most up-to-date genome annotation for both coding sequences and intergenic regions. In the presence of acetate, 8b still can utilize all the glucose (though xylose utilization was inhibited) with similar ethanol yield although the growth, final biomass, and ethanol production rate were reduced. The presence of acetate caused genes related to biosynthesis, flagellar system, and glycolysis to be downregulated, and genes related to stress responses and energy metabolism to be upregulated. Our result indicates that Z. mobilis utilized different mechanism for xylose utilization compared to that of glucose, with even more dramatic results than those caused by treatment of the culture with the inhibitor acetate. Our study also suggests that redox imbalance caused by stressful conditions may trigger a metabolic reaction that leads to the accumulation of toxic intermediates such as xylitol, but Z. mobilis appears to be capable of managing its carbon and energy metabolism through the control of individual reactions to overcome the inhibition caused by stressful conditions. Several target gene candidates based on transcriptomic result have been selected for genetic manipulation and a TonB-dependent receptor knockout mutant was confirmed to have advantage on acetate tolerance. Conclusions: We have gained insights into the molecular responses of the model ethanologenic bacterium Z. mobilis to the inhibitor acetate when grown in different sugar sources. These insights will facilitate future metabolic modeling studies and help further strain metabolic engineering efforts for better xylose utilization and acetate tolerance. Two series of microarray studies using total RNA extracted from Zymomonas mobilis subsp mobilis 8b (an xylose-utilizing recombinant) were carried out to investigate the effect of carbon source and acetate on Z. mobilis. One study compared the acetate effect in either glucose or xylose at exponential phase and another study investigated the acetate effect in mixed sugar of glucose and xylose at three growth phases of exponential, transition, and stationary. Tthree biological replicates were used for each condition.
2014-09-08 | E-GEOD-57553 | biostudies-arrayexpress