Microbial Metabolite Export

Eggeling, Lothar

doi:10.1002/9780470054581.eib426

Cited by 6 publications

(5 citation statements)

References 102 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This observation provides an opportunity of influencing the read-out properties of a sensor that had not previously been taken into consideration. As demonstrated for the production of antibiotics [ 16 ], amino acids [ 17 ], and biofuels [ 4 ], small-molecule production depends on export proteins. The ability to manipulate export activities permits cytosolic concentration of the substrate to be increased or decreased, which may be helpful, for example, when using strains that display high productivity and high cytosolic concentrations of substrate.…”

Section: Resultsmentioning

confidence: 99%

A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

et al. 2012

Self Cite

View full text Add to dashboard Cite

We present a novel method for visualizing intracellular metabolite concentrations within single cells of Escherichia coli and Corynebacterium glutamicum that expedites the screening process of producers. It is based on transcription factors and we used it to isolate new L-lysine producing mutants of C. glutamicum from a large library of mutagenized cells using fluorescence-activated cell sorting (FACS). This high-throughput method fills the gap between existing high-throughput methods for mutant generation and genome analysis. The technology has diverse applications in the analysis of producer populations and screening of mutant libraries that carry mutations in plasmids or genomes.

show abstract

Section: Resultsmentioning

confidence: 99%

A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

et al. 2012

Self Cite

View full text Add to dashboard Cite

show abstract

“…Further characterization of the entire transport system of CefA and CefB is required, including its substrate specificity and other important kinetic factors as a transporter, as well as its optimal expression levels. Managing unwanted production due to leakage via a transporter as a consequence of relaxed substrate specificity and its fine-tuned expression levels to prevent the disturbance of important cellular processes are general challenges in the development of amino acid fermentation (47). Finally, P. ananatis is more tolerant to environmental stresses than E. coli, particularly acidic conditions (23,31).…”

Section: Takumi Et Almentioning

confidence: 99%

Fermentative Production of Cysteine by Pantoea ananatis

Takumi

Ziyatdinov

Samsonov

et al. 2017

Appl Environ Microbiol

View full text Add to dashboard Cite

Cysteine is a commercially important amino acid; however, it lacks an efficient fermentative production method. Due to its cytotoxicity, intracellular cysteine levels are stringently controlled via several regulatory modes. Managing its toxic effects as well as understanding and deregulating the complexities of regulation are crucial for establishing the fermentative production of cysteine. The regulatory modes include feedback inhibition of key metabolic enzymes, degradation, efflux pumps, and the transcriptional regulation of biosynthetic genes by a master cysteine regulator, CysB. These processes have been extensively studied using Escherichia coli for overproducing cysteine by fermentation. In this study, we genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to identify key factors required for cysteine production. According to this and our previous studies, we identified a major cysteine desulfhydrase gene, ccdA (formerly PAJ_0331), involved in cysteine degradation, and the cysteine efflux pump genes cefA and cefB (formerly PAJ_3026 and PAJ_p0018, respectively), which may be responsible for downregulating the intracellular cysteine level. Our findings revealed that ccdA deletion and cefA and cefB overexpression are crucial factors for establishing fermentative cysteine production in P. ananatis and for obtaining a higher cysteine yield when combined with genes in the cysteine biosynthetic pathway. To our knowledge, this is the first demonstration of cysteine production in P. ananatis, which has fundamental implications for establishing overproduction in this microbe.IMPORTANCE The efficient production of cysteine is a major challenge in the amino acid fermentation industry. In this study, we identified cysteine efflux pumps and degradation pathways as essential elements and genetically engineered Pantoea ananatis, an emerging host for the fermentative production of bio-based materials, to establish the fermentative production of cysteine. This study provides crucial insights into the design and construction of cysteine-producing strains, which may play central roles in realizing commercial basis production.

show abstract

“…Even proline export has not been elucidated in detail. Whereas several more or less specific export systems are known for many amino acids (Eggeling, ), for proline, such a system remains to be identified among the roughly 180 candidate exporter genes in the C. glutamicum genome (Marin and Krämer, ; Winnen et al, ). Alternatively, proline export may be established via transporters involved in osmoprotection, for which proline functions as a compatible solute (Culham et al, ; Wood, ).…”

Section: Discussionmentioning

confidence: 99%

Efficient hydroxyproline production from glucose in minimal media by Corynebacterium glutamicum

Falcioni

Bühler

Schmid

2014

Biotech & Bioengineering

View full text Add to dashboard Cite

The efficient coupling of biotransformation steps to an existing fermentation pathway is an interesting strategy to expand the product portfolio of Corynebacterium glutamicum as whole-cell biocatalyst. This is especially challenging if the biotransformation step comprises a direct link to central metabolism, as in the case of α-ketoglutarate-dependent oxygenase catalysis. Aiming at trans-4-hydroxy-L-proline (Hyp) production from glucose in a minimal medium, the proline-4-hydroxylase gene from Dactylosporangium sp. strain RH1 was introduced into a proline-producing, isoleucine-bradytroph C. glutamicum strain. The production of proline was found to be induced by isoleucine limitation. Proline and Hyp production were found to depend differently on isoleucine limitation. Severe isoleucine limitation was shown to result in proline accumulation and low hydroxylation rates both in batch and continuous cultivation set-ups. The investigation of different steady states with various glucose/isoleucine molar ratios revealed that optimal conditions for Hyp production are met around a molar ratio of 46:1, where isoleucine limitation is sufficient to trigger proline production but the hydroxylation rate is high enough to convert the majority of formed proline to Hyp. A high cell-density fed-batch set-up was designed, capable of producing 7.1 g L(-1) of Hyp from glucose in 23 h with 98.5% conversion of proline to Hyp. Reaction engineering, specifically the fine-tuning of the glucose/isoleucine concentration ratio, enabled control of the fermentation profile and thus the accumulation of the desired product Hyp from glucose in minimal and defined media.

show abstract

Microbial Metabolite Export

Cited by 6 publications

References 102 publications

A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

A high-throughput approach to identify genomic variants of bacterial metabolite producers at the single-cell level

Fermentative Production of Cysteine by Pantoea ananatis

Efficient hydroxyproline production from glucose in minimal media by Corynebacterium glutamicum

Contact Info

Product

Resources

About