Dynamics of pyruvate metabolism in <i>Lactococcus lactis</i>

Melchiorsen, Claus Rix; Jensen, Niels Bang Siemsen; Christensen, Bjarke Bak; Jokumsen, Kirsten Væver; Villadsen, John

doi:10.1002/bit.1117

Cited by 42 publications

(2 citation statements)

References 16 publications

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“…The fact that pyruvate formate lyase in L. lactis is repressed by glucose and allosterically inhibited by glycolytic intermediates (48,49), strongly indicates such a switch in strategy. Also studies on adaptive evolution in E. coli have shown that some winning strategies showed inefficient (overflow) metabolism, depending on the substrate (50).…”

Section: Discussionmentioning

confidence: 99%

Analysis of Growth of Lactobacillus plantarum WCFS1 on a Complex Medium Using a Genome-scale Metabolic Model

Teusink

Wiersma

Molenaar

et al. 2006

Journal of Biological Chemistry

255

271

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A genome-scale metabolic model of the lactic acid bacterium Lactobacillus plantarum WCFS1 was constructed based on genomic content and experimental data. The complete model includes 721 genes, 643 reactions, and 531 metabolites. Different stoichiometric modeling techniques were used for interpretation of complex fermentation data, as L. plantarum is adapted to nutrient-rich environments and only grows in media supplemented with vitamins and amino acids. (i) Based on experimental input and output fluxes, maximal ATP production was estimated and related to growth rate. (ii) Optimization of ATP production further identified amino acid catabolic pathways that were not previously associated with free-energy metabolism. (iii) Genome-scale elementary flux mode analysis identified 28 potential futile cycles. (iv) Flux variability analysis supplemented the elementary mode analysis in identifying parallel pathways, e.g. pathways with identical end products but different co-factor usage. Strongly increased flexibility in the metabolic network was observed when strict coupling between catabolic ATP production and anabolic consumption was relaxed. These results illustrate how a genome-scale metabolic model and associated constraint-based modeling techniques can be used to analyze the physiology of growth on a complex medium rather than a minimal salts medium. However, optimization of biomass formation using the Flux Balance Analysis approach, reported to successfully predict growth rate and by product formation in Escherichia coli and Saccharomyces cerevisiae, predicted too high biomass yields that were incompatible with the observed lactate production. The reason is that this approach assumes optimal efficiency of substrate to biomass conversion, and can therefore not predict the metabolically inefficient lactate formation.Genome-scale metabolic models have become available for an increasing number of organisms (1). These models link genomic information to metabolic reaction networks and have gained considerable attention, not only within the context of metabolic engineering (2, 3), but also from the bioinformatics field (4, 5). An increasing repertoire of modeling techniques is available for exploring the capabilities of the metabolic network, and for understanding genotype-phenotype relationships (2, 6). These techniques are often referred to as constraint-based modeling techniques.So far, constraint-based modeling techniques have mainly been applied to microorganisms that grow on a minimal salt medium containing a single carbon source (1). However, in many biological niches, as well as in multicellular organisms, cells encounter more complex nutritional environments. In analogy, in many industrial and biotechnological applications of microorganisms and cell lines, complex media are used, either because the cells are auxotrophic for nutrients or such media are cheaper. Multiple inputs for the metabolic network complicate constraint-based modeling approaches considerably. Moreover, one may expect quite different metabolic ...

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Section: Discussionmentioning

confidence: 99%

Analysis of Growth of Lactobacillus plantarum WCFS1 on a Complex Medium Using a Genome-scale Metabolic Model

Teusink

Wiersma

Molenaar

et al. 2006

Journal of Biological Chemistry

255

271

View full text Add to dashboard Cite

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“…It is observed that cell growth, on a single limiting substrate, in terms of , is proportional to substrate concentration, S, at low concentrations. At higher concentrations of S, µ attains maximum value and remains constant and this can be described by Monod model [14,19] represented by equation 11.…”

Section: Modeling Of Reaction Kineticsmentioning

confidence: 99%

Modeling of reaction kinetics in generation of hydrogen from wastewater by microbial electrolysis

Meda¹,

Amritanatan²,

Parappa³

2021

E3S Web Conf.

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High carbon footprints and limited availability of fossil fuels have motivated researchers to find alternatives to fossil fuels and the ways of producing them. Hydrogen is an alternative fuel and can be generated by electrohydrogenesis in a Microbial Electrolysis Cell (MEC) using wastewater. At times, the microorganisms known as exoelectrogens are added externally to the wastewater in the form of biomass. Biomass serves as a parameter to optimize the yield of hydrogen. In this research work an attempt is made to understand the effect of the biomass concentration on the substrate utilization by the exoelectrogens and product formation. This research work also aims at studying the biochemical reaction kinetics and to identify a model that best describes the kinetics of the reactions involved, at the electrodes. It was observed that on increasing the biomass concentration from 0.7g/L to 1.4 g/L, the gas liberation rate increased from 9.42 ml/day to 15.33 ml/day and substrate utilization increased from 86.8% to 94.3%. This was in close agreement with the solution of the identified model. It was found out that the energy efficiency of MEC improved substantially by 30% and the energy demand was decreased by 38.5% when the initial biomass concentration was doubled.

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Kinetics of Bio‐Reactions

Villadsen

2015

Fundamental Bioengineering

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Dynamics of pyruvate metabolism in Lactococcus lactis

Cited by 42 publications

References 16 publications

Analysis of Growth of Lactobacillus plantarum WCFS1 on a Complex Medium Using a Genome-scale Metabolic Model

Analysis of Growth of Lactobacillus plantarum WCFS1 on a Complex Medium Using a Genome-scale Metabolic Model

Modeling of reaction kinetics in generation of hydrogen from wastewater by microbial electrolysis

Kinetics of Bio‐Reactions

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