Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA227284 | ENA |
REPOSITORIES: ENA
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Project description:Its characteristic rose-like aroma makes phenylethanol a popular ingredient in foods, beverages and cosmetics. Microbial production of phenylethanol currently relies on whole-cell bioconversion of phenylalanine with yeasts that harbor an Ehrlich pathway for phenylalanine catabolism. Complete biosynthesis of phenylethanol from a cheap carbon source such as glucose provides an economically attractive alternative for phenylalanine bioconversion. In this study, a Synthetic Genetic Array screening was applied to identify genes involved in regulation of phenylethanol synthesis in Saccharomyces cerevisiae. The screen focused on transcriptional regulation of ARO10, which encodes the major decarboxylase involved in conversion of phenylpyruvate to phenylethanol. A deletion in ARO8, which encodes an aromatic amino acid transaminase, was found to cause a transcriptional upregulation of ARO10 during growth with ammonium sulfate as the sole nitrogen source. Physiological characterization revealed that the aro8 mutation led to substantial changes in the absolute and relative intracellular concentrations of amino acids. Moreover, deletion of ARO8 led to de novo production of phenylethanol during growth on a glucose synthetic medium with ammonium as the sole nitrogen source. The aro8 mutation also stimulated phenylethanol production when combined with other, previously documented mutations that deregulate aromatic amino acid biosynthesis in S. cerevisiae. The resulting engineered S. cerevisiae strain produced over 3 mM of phenylethanol from glucose during growth on a simple synthetic medium. The strong impact of a transaminase deletion on intracellular amino acid concentrations opens new possibilities for yeast-based production of amino acid-derived products.
2014-03-19 | GSE52256 | GEO
Project description:Its characteristic rose-like aroma makes phenylethanol a popular ingredient in foods, beverages and cosmetics. Microbial production of phenylethanol currently relies on whole-cell bioconversion of phenylalanine with yeasts that harbor an Ehrlich pathway for phenylalanine catabolism. Complete biosynthesis of phenylethanol from a cheap carbon source such as glucose provides an economically attractive alternative for phenylalanine bioconversion. In this study, a Synthetic Genetic Array screening was applied to identify genes involved in regulation of phenylethanol synthesis in Saccharomyces cerevisiae. The screen focused on transcriptional regulation of ARO10, which encodes the major decarboxylase involved in conversion of phenylpyruvate to phenylethanol. A deletion in ARO8, which encodes an aromatic amino acid transaminase, was found to cause a transcriptional upregulation of ARO10 during growth with ammonium sulfate as the sole nitrogen source. Physiological characterization revealed that the aro8M-oM-^AM-^D mutation led to substantial changes in the absolute and relative intracellular concentrations of amino acids. Moreover, deletion of ARO8 led to de novo production of phenylethanol during growth on a glucose synthetic medium with ammonium as the sole nitrogen source. The aro8 mutation also stimulated phenylethanol production when combined with other, previously documented mutations that deregulate aromatic amino acid biosynthesis in S. cerevisiae. The resulting engineered S. cerevisiae strain produced over 3 mM of phenylethanol from glucose during growth on a simple synthetic medium. The strong impact of a transaminase deletion on intracellular amino acid concentrations opens new possibilities for yeast-based production of amino acid-derived products. The goal of the present study was to identify genes that influence the transcriptional (de)repression of the Ehrlich pathway during growth with ammonium as the nitrogen source. With the aid of Synthetic Genetic Array technology, we constructed a strain collection in which deletions in the non-essential genes in the S. cerevisiae genome were combined with a reporter plasmid comprising the ARO10 promoter fused to a reporter gene (egfp) encoding a fluorescent reporter protein. After screening by flow cytometry, deletion of ARO8 led to a deregulated expression from the ARO10 promoter. The impact of this deletion was further studied by transcriptome and intracellular metabolite analyses. Furthermore, phenylethanol production was measured in strains that combined the aro8 mutation with mutations that were previously shown to deregulate aromatic amino acid biosynthesis.
2014-03-19 | E-GEOD-52256 | biostudies-arrayexpress
Project description:We aimed to study how production of p-coumaric acid, a precursor of multiple secondary aromatic metabolites, influences the cellular metabolism of Saccharomyces cerevisiae. We evaluated the growth and p-coumaric acid production in batch and chemostat cultivations and analyzed the transcriptome and intracellular metabolome during steady state in low- and high-producers of p-coumaric acid in two strain backgrounds, S288c or CEN.PK. For analysis of the differential gene expression, we did pairwise comparisons between the optimized and non-optimized strains for p-CA production: CEN.PK strains (ST4288 and ST4408) and the S288c strains (ST4353 and ST4397). Transcriptome analysis showed that the CEN.PK strain was less affected by engineering towards higher p-CA production than the S288c strain, as the number of significantly up-/down-regulated genes was correspondingly 652 and 1927 amongst others, strain S288c had downregulations in gene sets involved in amino acid and protein biosynthesis. This suggests that CEN.PK may be a better platform strain for production of aromatic compounds than the S288c strain.
2017-11-21 | E-MTAB-6208 | biostudies-arrayexpress
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:Different transcriptome, metabolome, and phosphoproteome studies have already indicated a regulatory role of Ser/Thr phosphorylation in the central metabolism of S. aureus. However, it remains still unknown how this exactly tunes its metabolism. For that reason, Extreme Pathway Analysis was used to understand metabolic flux regulation by Ser/Thr phosphorylation. YANAsquare software and YANAvergence routine were chosen to calculate pathway activities of WT, ΔpknB, Δstp, and double mutant S. aureus NewmanHG strains. Gene expression data of S. aureus NewmanHG were collected taking the wild type and mutations of kinase (pknB), phosphatase (stp) or both (pknB/stp) phenotypes. The resulting flux changes were modelled with YANAvergence taking the different gene expression data and an established genome scale model of S. aureus metabolic modes as basis. The fluxes of the different strains were next calculated, taking the gene expression data into account. A concerted metabolic change of fluxes was observed. In particular the pathways for peptidoglycan, nucleotide, and aromatic amino acid synthesis as well as catabolism involving aspartate transaminase (GOT) changed significantly compared to the wild type. Single mutations of pknB and stp were compared to illustrate their different contribution to the phenotype, e.g. pyrimidine synthesis is dramatically impaired by pknB deletion but much less by loss of stp. In the double knock out strain, there is higher activity of peptidoglycan, purine, and aromatic amino acids synthesis from glucose, but lower activity of pyrimidine synthesis from glucose compared to WT. The results suggest a probable regulatory role of Ser/Thr phosphorylation in amino acid catabolism and the glycolysis/gluconeogenesis switch to provide the cell with sufficient cell wall components, nucleotides, and aromatic amino acids. Yvck is suggested to serve as regulatory protein linking Ser/Thr phosphorylation to the previous results of S. aureus metabolism. Moreover, Yvck seems in particular to be involved in the switch between glycolysis and gluconeogenesis. However, further studies based on experimental approaches are needed to demonstrate that Ser/Thr phosphorylation and Yvck are necessary for a correct cell growth under gluconeogenic conditions. The metabolic model allows not only a comprehensive representation of these changes for all involved pathways in the four strains, it further points out the function of the previously unannotated ycvk operon.. The relevance of these specific metabolic pathway adaptations regarding the pathogenicity of S.aureus and their contributions to the infection process will be analyzed and discussed.
2019-11-11 | GSE122362 | 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:Phenylethanol-resistant S. cerevisiae mutants were obtained by using evolutionary engineering strategy. Briefly, a chemically mutagenized culture was used as the initial population for the selection procedure. Gradually increasing levels of phenylethanol stress was applied through 56 successive batch cultivations. Individual mutants were selected from the final population. The mutant with the highest phenylethanol resistance could resist up to 3 g/L phenylethanol concentrations. Whole-genome transcriptomic analyses of the phenylethanol-resistant mutant strain and the reference strain were performed by using DNA microarray technology, in the absence of phenylethanol stress.
2014-07-12 | GSE59353 | GEO
Project description:The objective of this study was to analyze AHR activation through aromatic amino acid metabolism. To this end, glioblastoma cells were exposed to aromatic amino acid derived metabolites and their ability to activate AHR was analysed. In addition, AHR activation was evaluated in glioblastoma cells expressing IL4I1, an aromatic amino acid degrading enzyme, with or without shRNA mediated knockdown of AHR.
2020-08-19 | GSE129977 | GEO
Project description:The objective of this study was to analyze AHR activation through aromatic amino acid metabolism. To this end, glioblastoma cells were exposed to aromatic amino acid derived metabolites and their ability to activate AHR was analysed. In addition, AHR activation was evaluated in glioblastoma cells expressing IL4I1, an aromatic amino acid degrading enzyme, with or without shRNA mediated knockdown of AHR.
2020-08-19 | GSE129976 | GEO
Project description:The objective of this study was to analyze AHR activation through aromatic amino acid metabolism. To this end, glioblastoma cells were exposed to aromatic amino acid derived metabolites and their ability to activate AHR was analysed. In addition, AHR activation was evaluated in glioblastoma cells expressing IL4I1, an aromatic amino acid degrading enzyme, with or without shRNA mediated knockdown of AHR.
2020-08-19 | GSE129974 | GEO