Effect of pyruvate dehydrogenase complex deficiency on l-lysine production with Corynebacterium glutamicum

Blombach, Bastian; Schreiner, Mark E.; Moch, Matthias; Oldiges, Marco; Eikmanns, Bernhard J.

doi:10.1007/s00253-007-0904-1

Cited by 60 publications

(43 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In view of many biotechnological productions where pyruvate and acetate represent unwanted by-products, knowledge of the relevant transporter systems is of significance. During valine or lysine production by C. glutamicum, for example, pyruvate excretion was observed and lowered the product yield (5,6). By overexpression of the cg0952-mctC operon, pyruvate reutilization could be achieved and thereby carbon loss prevented.…”

Section: Discussionmentioning

confidence: 99%

Identification and Characterization of a Bacterial Transport System for the Uptake of Pyruvate, Propionate, and Acetate in Corynebacterium glutamicum

et al. 2009

Self Cite

View full text Add to dashboard Cite

The metabolism of monocarboxylic acids is of central importance for bacteria in their natural habitat as well as during biotechnological production. Although biosynthesis and degradation are well understood, the transport of such compounds is still a matter of discussion. Here we present the identification and characterization of a new transport system in Corynebacterium glutamicum with high affinity for acetate and propionate and with lower affinity for pyruvate. Biochemical analysis of this monocarboxylic acid transporter (MctC) revealed for the first time a quantitative discrimination of passive diffusion and active transport of acetate by bacterial cells. MctC is a secondary transporter and belongs to the class of sodium solute symporters, but it is driven by the electrochemical proton potential. The mctC gene is preceded by and cotranscribed with cg0952, a locus encoding a small membrane protein, and the transcription of the cg0952-mctC operon is under the control of the transcriptional regulators RamA and RamB. Both of these proteins directly bind to the promoter region of the operon; RamA is essential for expression and RamB exerts a slightly negative control on expression of the cg0952-mctC operon. mctC expression is induced in the presence of pyruvate and beneficial under substratelimiting conditions for C. glutamicum.Corynebacterium glutamicum is one of the major work horses in industrial biotechnology. More than 1.5 million tons of glutamate as well as 0.75 million tons of lysine per year are produced with the use of this bacterium (25,27). C. glutamicum is a nonmotile, gram-positive bacterium and is able to utilize a number of carbon sources, including sugars such as glucose, fructose, and sucrose, organic acids such as gluconate, acetate, propionate, pyruvate, and L-lactate, ethanol, and also amino acids such as glutamate and serine (9,10,30,31). The utilization of tri-and dicarboxylates by C. glutamicum depends on the expression and/or activity of the relevant transport systems, as shown recently (37, 45). Monocarboxylic acids like acetate and propionate are abundant carbon sources in soil and also unwanted by-products in fermentation processes (44). The utilization of acetate by C. glutamicum involves the activation of acetate by the combined activities of acetate kinase and phosphotransacetylase and the subsequent flux into the tricarboxylic acid and glyoxylate cycles (17). However, the uptake of acetate by C. glutamicum cells is not yet understood. It has been proposed that a specific secondary uptake system is involved and that passive diffusion does not significantly contribute at pH 8 or with low substrate concentrations (14). On the other hand, a discrepancy between the relatively low uptake rates observed by Ebbinghausen et al. (14) and the much higher consumption rates of acetate during growth experiments, as well as the long lag phase after addition of higher (Ͼ2%) concentrations of acetate, point to diffusion being relevant for the utilization of this particular substrate (17, 43). Also...

show abstract

Section: Discussionmentioning

confidence: 99%

Identification and Characterization of a Bacterial Transport System for the Uptake of Pyruvate, Propionate, and Acetate in Corynebacterium glutamicum

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…3). One mutation (aceE) affected pyruvate dehydrogenase, the inactivation of which has been recently shown to cause pyruvate accumulation and valine secretion (5,6). The sspA and tufA mutations affect the protein synthesis rate, and the amino acid pool utilization may be also associated with a reduced pyruvate utilization.…”

Section: Discussionmentioning

confidence: 99%

The Amino Acid Valine Is Secreted in Continuous-Flow Bacterial Biofilms

Valle

Schmid

et al. 2008

J Bacteriol

View full text Add to dashboard Cite

Biofilms are structured communities characterized by distinctive gene expression patterns and profound physiological changes compared to those of planktonic cultures. Here, we show that many gram-negative bacterial biofilms secrete high levels of a small-molecular-weight compound, which inhibits the growth of only Escherichia coli K-12 and a rare few other natural isolates. We demonstrate both genetically and biochemically that this molecule is the amino acid valine, and we provide evidence that valine production within biofilms results from metabolic changes occurring within high-density biofilm communities when carbon sources are not limiting. This finding identifies a natural environment in which bacteria can encounter high amounts of valine, and we propose that in-biofilm valine secretion may be the long-sought reason for widespread but unexplained valine resistance found in most enterobacteria. Our results experimentally validate the postulated production of metabolites that is characteristic of the conditions associated with some biofilm environments. The identification of such molecules may lead to new approaches for biofilm monitoring and control.Biofilms are matrix-encased bacterial communities that develop on most surfaces and often constitute a reservoir of bacterial pathogens. Detrimental biofilms are difficult to eradicate due to a characteristic tolerance to biocides. They cause serious health and economic problems when they form on medical and industrial devices (11,19,24). While biofilmassociated antibiotic tolerance is considered a major physiological trait that distinguishes free cells from surface-attached cells, biofilms are also characterized by gene expression patterns that are distinctive compared to those of planktonic cultures (4,35,40,41,58). These changes are likely to result from modifications of growth conditions within biofilms, and they have been proposed to correspond to ill-understood responses triggered by the biofilm lifestyle (3,26).Recently, studies conducted with simplified, mixed communities composed of two bacterial species revealed that biofilm bacteria express competitive or cooperative behavior that does not take place within classical planktonic cultures (7,22). These results suggested that biofilm-associated weaponry could contribute to the dynamics of bacterial biofilm populations. However, thus far, the production of molecules involved in antagonistic bacterial relationships within biofilms has been poorly investigated.Here we show that the continuous-flow biofilms formed by many Escherichia coli strains and other gram-negative bacteria accumulate high levels of a small-molecular-weight compound with inhibitory activity against E. coli K-12 strains. We demonstrate both genetically and biochemically that this compound is the amino acid valine. We provide evidence that valine secretion within biofilms could be the cause of the longknown but unexplained widespread valine resistance observed for most enterobacteria. Beyond the biological significance of in-biofilm valin...

show abstract

“…Growth was monitored by measuring the optical density at 600 nm (OD 600 ). The cell mass (dry weight) was calculated from the OD 600 by using a ratio of 0.3 g of cells (dry weight) (CDW) liter Ϫ1 per OD 600 unit (11).…”

Section: Methodsmentioning

confidence: 99%

Arabitol Metabolism of Corynebacterium glutamicum and Its Regulation by AtlR

Laslo

Zaluskowski

Gabris

et al. 2011

Journal of Bacteriology

View full text Add to dashboard Cite

Expression profiling of Corynebacterium glutamicum in comparison to a derivative deficient in the transcriptional regulator AtlR (previously known as SucR or MtlR) revealed eight genes showing more than 4-fold higher mRNA levels in the mutant. Four of these genes are located in the direct vicinity of the atlR gene, i.e., xylB, rbtT, mtlD, and sixA, annotated as encoding xylulokinase, the ribitol transporter, mannitol 2-dehydrogenase, and phosphohistidine phosphatase, respectively. Transcriptional analysis indicated that atlR and the four genes are organized as atlR-xylB and rbtT-mtlD-sixA operons. Growth experiments with C. glutamicum and C. glutamicum ⌬atlR, ⌬xylB, ⌬rbtT, ⌬mtlD, and ⌬sixA derivatives with sugar alcohols revealed that (

show abstract

Effect of pyruvate dehydrogenase complex deficiency on l-lysine production with Corynebacterium glutamicum

Cited by 60 publications

References 24 publications

Identification and Characterization of a Bacterial Transport System for the Uptake of Pyruvate, Propionate, and Acetate in Corynebacterium glutamicum

Identification and Characterization of a Bacterial Transport System for the Uptake of Pyruvate, Propionate, and Acetate in Corynebacterium glutamicum

The Amino Acid Valine Is Secreted in Continuous-Flow Bacterial Biofilms

Arabitol Metabolism of Corynebacterium glutamicum and Its Regulation by AtlR

Contact Info

Product

Resources

About