Glucose consumption rate critically depends on redox state in Corynebacterium glutamicum under oxygen deprivation

2015 ◽  
Vol 99 (13) ◽  
pp. 5573-5582 ◽  
Author(s):  
Yota Tsuge ◽  
Kimio Uematsu ◽  
Shogo Yamamoto ◽  
Masako Suda ◽  
Hideaki Yukawa ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Redox State ◽  
Consumption Rate ◽  
Glucose Consumption ◽  
Oxygen Deprivation ◽  
Glucose Consumption Rate

scholarly journals Group 2 Sigma Factor SigB of Corynebacterium glutamicum Positively Regulates Glucose Metabolism under Conditions of Oxygen Deprivation

2008 ◽  
Vol 74 (16) ◽  
pp. 5146-5152 ◽  
Author(s):  
Shigeki Ehira ◽  
Tomokazu Shirai ◽  
Haruhiko Teramoto ◽  
Masayuki Inui ◽  
Hideaki Yukawa
Keyword(s):  
Glucose Metabolism ◽  
Organic Acids ◽  
Corynebacterium Glutamicum ◽  
Sigma Factor ◽  
Glucose Consumption ◽  
Oxygen Deprivation ◽  
Glucose Consumption Rate ◽  
Transcript Levels ◽  
High Productivity ◽  
Group 2

ABSTRACT The sigB gene of Corynebacterium glutamicum encodes a group 2 sigma factor of RNA polymerase. Under conditions of oxygen deprivation, the sigB gene is upregulated and cells exhibit high productivity of organic acids as a result of an elevated glucose consumption rate. Using DNA microarray and quantitative reverse transcription-PCR (RT-PCR) analyses, we found that sigB disruption led to reduced transcript levels of genes involved in the metabolism of glucose into organic acids. This in turn resulted in retardation of glucose consumption by cells under conditions of oxygen deprivation. These results indicate that SigB is involved in positive regulation of glucose metabolism genes and enhances glucose consumption under conditions of oxygen deprivation. Moreover, sigB disruption reduced the transcript levels of genes involved in various cellular functions, including the glucose metabolism genes not only in the growth-arrested cells under conditions of oxygen deprivation but also in the cells during aerobic exponential growth, suggesting that SigB functions as another vegetative sigma factor.

Biofilm monitoring: a perfect solution in search of a problem

2003 ◽  
Vol 47 (5) ◽  
pp. 9-18 ◽  
Author(s):  
Z. Lewandowski ◽  
H. Beyenal
Keyword(s):  
Consumption Rate ◽  
Glucose Consumption ◽  
Data Interpretation ◽  
Integrated System ◽  
Glucose Consumption Rate ◽  
Biofilm Heterogeneity

The main problem with monitoring biofilms is data interpretation. Biofilm heterogeneity causes monitored parameters to vary from location to location in the same biofilm, and it is difficult to assess to what extent these variations are caused by biofilm heterogeneity and to what extent they reflect other properties of the biofilm. We have used the concept of discretized biofilms, which is an integrated system of biofilm monitoring and data interpretation, to assess the effect of biofilm heterogeneity on biofilm activity. Using this approach we have estimated that a heterogeneous biofilm can be ten times more active, in terms of glucose consumption rate, than a homogeneous biofilm of the same thickness but with uniformly distributed density.

scholarly journals Influence of static magnetic fields on S. cerevisae biomass growth

2007 ◽  
Vol 50 (3) ◽  
pp. 515-520 ◽  
Author(s):  
João B. Muniz ◽  
Milton Marcelino ◽  
Mauricio da Motta ◽  
Alexandre Schuler ◽  
Mauricy Alves da Motta
Keyword(s):  
Magnetic Fields ◽  
Consumption Rate ◽  
Cylindrical Tube ◽  
Glucose Consumption ◽  
Dry Weight ◽  
Biomass Growth ◽  
Glucose Consumption Rate ◽  
Static Magnetic Fields ◽  
Tube Reactor ◽  
Flow Intensity

Biomass growth of Saccharomyces cerevisiae DAUFPE-1012 was studied in eight batch fermentations exposed to steady magnetic fields (SMF) running at 23ºC (± 1ºC), for 24 h in a double cylindrical tube reactor with synchronic agitation. For every batch, one tube was exposed to 220mT flow intensity SMF, produced by NdFeB rod magnets attached diametrically opposed (N to S) magnets on one tube. In the other tube, without magnets, the fermentation occurred in the same conditions. The biomass growth in culture (yeast extract + glucose 2%) was monitored by spectrometry to obtain the absorbance and later, the corresponding cell dry weight. The culture glucose concentration was monitored every two hours so as the pH, which was maintained between 4 and 5. As a result, the biomass (g/L) increment was 2.5 times greater in magnetized cultures (n=8) as compared with SMF non-exposed cultures (n=8). The differential (SMF-control) biomass growth rate (135%) was slightly higher than the glucose consumption rate (130 %) leading to increased biomass production of the magnetized cells.

scholarly journals Overflow Metabolism in Escherichia coli during Steady-State Growth: Transcriptional Regulation and Effect of the Redox Ratio

2006 ◽  
Vol 72 (5) ◽  
pp. 3653-3661 ◽  
Author(s):  
G. N. Vemuri ◽  
E. Altman ◽  
D. P. Sangurdekar ◽  
A. B. Khodursky ◽  
M. A. Eiteman
Keyword(s):  
Escherichia Coli ◽  
Consumption Rate ◽  
Nadh Oxidase ◽  
Glucose Consumption ◽  
Tca Cycle ◽  
Overflow Metabolism ◽  
Glucose Consumption Rate ◽  
Redox Ratio ◽  
E Coli ◽  
Acetate Formation

ABSTRACT Overflow metabolism in the form of aerobic acetate excretion by Escherichia coli is an important physiological characteristic of this common industrial microorganism. Although acetate formation occurs under conditions of high glucose consumption, the genetic mechanisms that trigger this phenomenon are not clearly understood. We report on the role of the NADH/NAD ratio (redox ratio) in overflow metabolism. We modulated the redox ratio in E. coli through the expression of Streptococcus pneumoniae (water-forming) NADH oxidase. Using steady-state chemostat cultures, we demonstrated a strong correlation between acetate formation and this redox ratio. We furthermore completed genome-wide transcription analyses of a control E. coli strain and an E. coli strain overexpressing NADH oxidase. The transcription results showed that in the control strain, several genes involved in the tricarboxylic acid (TCA) cycle and respiration were repressed as the glucose consumption rate increased. Moreover, the relative repression of these genes was alleviated by expression of NADH oxidase and the resulting reduced redox ratio. Analysis of a promoter binding site upstream of the genes which correlated with redox ratio revealed a degenerate sequence with strong homology with the binding site for ArcA. Deletion of arcA resulted in acetate reduction and increased the biomass yield due to the increased capacities of the TCA cycle and respiration. Acetate formation was completely eliminated by reducing the redox ratio through expression of NADH oxidase in the arcA mutant, even at a very high glucose consumption rate. The results provide a basis for studying new regulatory mechanisms prevalent at reduced NADH/NAD ratios, as well as for designing more efficient bioprocesses.

scholarly journals Overexpression of Genes Encoding Glycolytic Enzymes in Corynebacterium glutamicum Enhances Glucose Metabolism and Alanine Production under Oxygen Deprivation Conditions

2012 ◽  
Vol 78 (12) ◽  
pp. 4447-4457 ◽  
Author(s):  
Shogo Yamamoto ◽  
Wataru Gunji ◽  
Hiroaki Suzuki ◽  
Hiroshi Toda ◽  
Masako Suda ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Corynebacterium Glutamicum ◽  
Glucose Consumption ◽  
Glycolytic Enzyme ◽  
Oxygen Deprivation ◽  
Glycolytic Enzymes ◽  
Content Type ◽  
Extracellular Metabolites ◽  
High Copy Number Plasmid ◽  
Genes Encoding

ABSTRACTWe previously reported thatCorynebacterium glutamicumstrain ΔldhAΔppc+alaD+gapA, overexpressing glyceraldehyde-3-phosphate dehydrogenase-encodinggapA, shows significantly improved glucose consumption and alanine formation under oxygen deprivation conditions (T. Jojima, M. Fujii, E. Mori, M. Inui, and H. Yukawa, Appl. Microbiol. Biotechnol. 87:159–165, 2010). In this study, we employ stepwise overexpression and chromosomal integration of a total of four genes encoding glycolytic enzymes (herein referred to as glycolytic genes) to demonstrate further successive improvements inC. glutamicumglucose metabolism under oxygen deprivation. In addition togapA, overexpressing pyruvate kinase-encodingpykand phosphofructokinase-encodingpfkenabled strain GLY2/pCRD500 to realize respective 13% and 20% improved rates of glucose consumption and alanine formation compared to GLY1/pCRD500. Subsequent overexpression of glucose-6-phosphate isomerase-encodinggpiin strain GLY3/pCRD500 further improved its glucose metabolism. Notably, both alanine productivity and yield increased after each overexpression step. After 48 h of incubation, GLY3/pCRD500 produced 2,430 mM alanine at a yield of 91.8%. This was 6.4-fold higher productivity than that of the wild-type strain. Intracellular metabolite analysis showed thatgapAoverexpression led to a decreased concentration of metabolites upstream of glyceraldehyde-3-phosphate dehydrogenase, suggesting that the overexpression resolved a bottleneck in glycolysis. Changing ratios of the extracellular metabolites by overexpression of glycolytic genes resulted in reduction of the intracellular NADH/NAD+ratio, which also plays an important role on the improvement of glucose consumption. Enhanced alanine dehydrogenase activity using a high-copy-number plasmid further accelerated the overall alanine productivity. Increase in glycolytic enzyme activities is a promising approach to make drastic progress in growth-arrested bioprocesses.

scholarly journals Improvement of the Redox Balance Increases l-Valine Production by Corynebacterium glutamicum under Oxygen Deprivation Conditions

2011 ◽  
Vol 78 (3) ◽  
pp. 865-875 ◽  
Author(s):  
Satoshi Hasegawa ◽  
Kimio Uematsu ◽  
Yumi Natsuma ◽  
Masako Suda ◽  
Kazumi Hiraga ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Glucose Consumption ◽  
Redox Balance ◽  
Oxygen Deprivation ◽  
Limiting Factor ◽  
Acetohydroxy Acid Synthase ◽  
Content Type ◽  
Production And Consumption ◽  
Dehydrogenase Gene ◽  
Valine Biosynthesis

ABSTRACTProduction ofl-valine under oxygen deprivation conditions byCorynebacterium glutamicumlacking the lactate dehydrogenase geneldhAand overexpressing thel-valine biosynthesis genesilvBNCDEwas repressed. This was attributed to imbalanced cofactor production and consumption in the overalll-valine synthesis pathway: two moles of NADH was generated and two moles of NADPH was consumed per mole ofl-valine produced from one mole of glucose. In order to solve this cofactor imbalance, the coenzyme requirement forl-valine synthesis was converted from NADPH to NADH via modification of acetohydroxy acid isomeroreductase encoded byilvCand introduction ofLysinibacillus sphaericusleucine dehydrogenase in place of endogenous transaminase B, encoded byilvE. The intracellular NADH/NAD+ratio significantly decreased, and glucose consumption andl-valine production drastically improved. Moreover,l-valine yield increased and succinate formation decreased concomitantly with the decreased intracellular redox state. These observations suggest that the intracellular NADH/NAD+ratio, i.e., reoxidation of NADH, is the primary rate-limiting factor forl-valine production under oxygen deprivation conditions. Thel-valine productivity and yield were even better and by-products derived from pyruvate further decreased as a result of a feedback resistance-inducing mutation in the acetohydroxy acid synthase encoded byilvBN. The resultant strain produced 1,470 mMl-valine after 24 h with a yield of 0.63 mol mol of glucose−1, and thel-valine productivity reached 1,940 mM after 48 h.

scholarly journals Engineering of Corynebacterium glutamicum for High-Yield l-Valine Production under Oxygen Deprivation Conditions

2012 ◽  
Vol 79 (4) ◽  
pp. 1250-1257 ◽  
Author(s):  
Satoshi Hasegawa ◽  
Masako Suda ◽  
Kimio Uematsu ◽  
Yumi Natsuma ◽  
Kazumi Hiraga ◽  
...  
Keyword(s):  
Corynebacterium Glutamicum ◽  
Glucose Consumption ◽  
Resistant Mutant ◽  
Oxygen Deprivation ◽  
High Yield ◽  
Acetohydroxy Acid Synthase ◽  
Succinate Production ◽  
Content Type ◽  
High Productivity ◽  
By Products

ABSTRACTWe previously demonstrated efficientl-valine production by metabolically engineeredCorynebacterium glutamicumunder oxygen deprivation. To achieve the high productivity, a NADH/NADPH cofactor imbalance during the synthesis ofl-valine was overcome by engineering NAD-preferring mutant acetohydroxy acid isomeroreductase (AHAIR) and using NAD-specific leucine dehydrogenase fromLysinibacillus sphaericus. Lactate as a by-product was largely eliminated by disrupting the lactate dehydrogenase geneldhA. Nonetheless, a few other by-products, particularly succinate, were still produced and acted to suppress thel-valine yield. Eliminating these by-products therefore was deemed key to improving thel-valine yield. By additionally disrupting the phosphoenolpyruvate carboxylase geneppc, succinate production was effectively suppressed, but both glucose consumption andl-valine production dropped considerably due to the severely elevated intracellular NADH/NAD+ratio. In contrast, this perturbed intracellular redox state was more than compensated for by deletion of three genes associated with NADH-producing acetate synthesis and overexpression of five glycolytic genes, includinggapA, encoding NADH-inhibited glyceraldehyde-3-phosphate dehydrogenase. Inserting feedback-resistant mutant acetohydroxy acid synthase and NAD-preferring mutant AHAIR in the chromosome resulted in higherl-valine yield and productivity. Deleting the alanine transaminase geneavtAsuppressed alanine production. The resultant strain produced 1,280 mMl-valine at a yield of 88% mol mol of glucose−1after 24 h under oxygen deprivation, a vastly improved yield over our previous best.

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