Metabolic Network Analysis of an Adipoyl-7-ADCA-Producing Strain of Penicillium chrysogenum: Elucidation of Adipate Degradation

Thykaer, Jette; Christensen, Bjarke Bak; Nielsen, Jens

doi:10.1006/mben.2001.0218

Cited by 38 publications

(19 citation statements)

References 22 publications

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“…The principles illustrated above can be taken much further, and it may even be possible to locate specific biochemical reactions in different compartments in eukaryotic cells (5,21). Hua et al (11) identified the topology of the metabolic network in wild-type E. coli and in mutants with disruptions of phosphoglucomutase and glucose-6-phosphate dehydrogenase and subsequently quantified the metabolic fluxes in the networks identified.…”

Section: Identification Of Metabolic Network Topologiesmentioning

confidence: 99%

It Is All about MetabolicFluxes

2003

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In the field of genomics there has been a move towards the development of novel experimental techniques that enable analysis of all components of a certain kind in a biological system, and this has resulted in the appearance of new methods for analyzing the omes. Obviously, in a given cellular system it is attractive to measure all the mRNAs, all the proteins, a large number of the metabolites, a large fraction of protein-protein or protein-DNA interactions, and so on, but a fundamental problem in functional genomics is integration of the information obtained, i.e., how this information can be integrated and lead to new insights into the functioning of cellular processes. Bioinformatics and advanced computer models are continuously supplying new methods for integration of data, and surely progress in the field of systems biology will eventually result in an ability to describe cellular functions in silico. In the race to obtain large amounts of data for phenotypic characterization of different cellular systems, a relatively simple experimental technique for quantitative determination of metabolic fluxes has escaped the attention of a large part of the biological research community; this technique has been used primarily by researchers in the field of metabolic engineering (1). The technique is based on relatively old principles from biochemistry, namely, feeding of specifically 13 C-labeled substrates to the cell for characterization of the metabolism. However, with the development of the necessary mathematical framework for analysis of data obtained from this type of analysis it has become possible to obtain estimates for the fluxes in the different parts of the central carbon metabolism. This information is obviously interesting in connection with improving metabolite production by a given microbial cell, but as demonstrated in a paper in this issue of Journal of Bacteriology (11), it also provides a very powerful tool for functional analysis of different mutant cells. In this short commentary the use of this technique for functional analysis and the advantages and limitations of different techniques for flux quantification are discussed, and some of the underlying methods are reviewed, Finally, some future perspectives are given. METABOLIC NETWORKSCellular metabolism is represented by a large number of metabolic reactions that are involved in the conversion of the carbon source into building blocks needed for macromolecular biosynthesis. Furthermore, there are specific reactions that ensure the constant supply of Gibbs free energy via ATP and redox equivalents (generally in the form of the cofactor NADPH) needed for biosynthesis of macromolecules. This large number of metabolic reactions forms a so-called metabolic network inside the cells, and as a result of reconstruction of the complete metabolic networks in different bacteria (6,17,18) and in the yeast Saccharomyces cerevisiae (8), more insight into the function of complete metabolic networks has been obtained. These reconstructed metabolic networks can b...

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Section: Identification Of Metabolic Network Topologiesmentioning

confidence: 99%

It Is All about MetabolicFluxes

2003

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“…Co-catabolism of the unlabelled compound can then be traced in the labelling patterns of central metabolites, allowing identification of the degradative pathway. This approach was used in the elucidation of adipate degradation in a 7-aminocephalosporanic acid (adipoyl-7-ADCA) producing P. chrysogenum strain [44]. Production of adipoyl-7-ADCA in this strain has been achieved by the introduction of an expandase gene from Streptomyces clavuligerus in combination with feeding of adipate [3].…”

Section: Identification Of Pathwaysmentioning

confidence: 99%

“…Metabolism of adipate by P. chrysogenum is therefore undesirable in terms of overall process economy. In the study by Thykaer et al [44], degradation of unlabelled adipate was followed in P. chrysogenum during growth on [U- 13 C 6 ]. It was found that unlabelled carbon made its way into intermediates of the TCA-cycle, supporting an earlier hypothesis that adipate is degraded to succinyl CoA and acetyl CoA by b-oxidation.…”

Section: Identification Of Pathwaysmentioning

confidence: 99%

Control of Fluxes Towards Antibiotics and the Role of Primary Metabolism in Production of Antibiotics

Gunnarsson

Eliasson

Nielsen

2004

Molecular Biotechnolgy of Fungal Beta-Lactam Antibiotics and Related Peptide Synthetases

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“…However, the physiological characterization of two other recombinant strains of P. chrysogenum expressing the expandase gene from S. clavuligerus has shown an ability for P. chrysogenum to metabolize adipate at the end of batch cultivations (Robin et al, 2001). Recently, experiments with 13 C-labeled substrates showed that adipate degradation occurs by ␤-oxidation in the microbodies (Thykaer et al, 2002). Thus, formation of biomass from the side-chain precursor is likely to be a consequence of degradation of adipic acid via ␤-oxi- Table III.…”

Section: Discussionmentioning

confidence: 99%

Continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus: Growth yields and morphological characterization

Robin

Lettier

McIntyre

et al. 2003

Biotech & Bioengineering

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The growth stoichiometry of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus was determined in glucose-limited chemostat cultivations using a chemically defined medium. This strain produces adipoyl-7-aminodeacetoxycephalosporanic acid (ad-7-ADCA) when it is fed with adipic acid. The biomass yield and maintenance coefficients for the strain were similar to those found for penicillin-producing strains of Penicillium chrysogenum. The maximum specific growth rate in the chemostat was found to be 0.11 h(-1). Metabolic degradation of adipate was found to take place in significant amounts only at dilution rates below 0.03 h(-1). After three to five residence times, adipate degradation and ad-7-ADCA production disappeared, and this allowed determination of the biomass yield coefficient on adipate. The morphology was measured at different dilution rates and the mean total hyphal length and mean number of tips both increased with an increase in dilution rate from 0.015 to 0.065 h(-1). Both variables decreased when the dilution rate was increased above 0.065 h(-1). A correlation between mean total hyphal length and productivity of ad-7-ADCA was found.

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Metabolic Network Analysis of an Adipoyl-7-ADCA-Producing Strain of Penicillium chrysogenum: Elucidation of Adipate Degradation

Cited by 38 publications

References 22 publications

It Is All about MetabolicFluxes

It Is All about MetabolicFluxes

Control of Fluxes Towards Antibiotics and the Role of Primary Metabolism in Production of Antibiotics

Continuous cultivations of a Penicillium chrysogenum strain expressing the expandase gene from Streptomyces clavuligerus: Growth yields and morphological characterization

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