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Steady-state and transient-state analysis of growth and metabolite production in a Saccharomyces cerevisiae strain with reduced pyruvate-decarboxylase activity.
Biotechnol Bioeng. 1999; 66(1):42-50.BB

Abstract

Pyruvate decarboxylase is a key enzyme in the production of low-molecular-weight byproducts (ethanol, acetate) in biomass-directed applications of Saccharomyces cerevisiae. To investigate whether decreased expression levels of pyruvate decarboxylase can reduce byproduct formation, the PDC2 gene, which encodes a positive regulator of pyruvate-decarboxylase synthesis, was inactivated in the prototrophic strain S. cerevisiae CEN. PK113-7D. This caused a 3-4-fold reduction of pyruvate-decarboxylase activity in glucose-limited, aerobic chemostat cultures grown at a dilution rate of 0.10 h(-1). Upon exposure of such cultures to a 50 mM glucose pulse, ethanol and acetate were the major byproducts formed by the wild type. In the pdc2Delta strain, formation of ethanol and acetate was reduced by 60-70%. In contrast to the wild type, the pdc2Delta strain produced substantial amounts of pyruvate after a glucose pulse. Nevertheless, its overall byproduct formation was ca. 50% lower. The specific rate of glucose consumption after a glucose pulse to pdc2Delta cultures was about 40% lower than in wild-type cultures. This suggests that, at reduced pyruvate-decarboxylase activities, glycolytic flux is controlled by NADH reoxidation. In aerobic, glucose-limited chemostat cultures, the wild type exhibited a mixed respiro-fermentative metabolism at dilution rates above 0.30 h(-1). Below this dilution rate, sugar metabolism was respiratory. At dilution rates up to 0.20 h(-1), growth of the pdc2Delta strain was respiratory and biomass yields were similar to those of wild-type cultures. Above this dilution rate, washout occurred. The low micro(max) of the pdc2Delta strain in glucose-limited chemostat cultures indicates that occurrence of respiro-fermentative metabolism in wild-type cultures is not solely caused by competition of respiration and fermentation for pyruvate. Furthermore, it implies that inactivation of PDC2 is not a viable option for reducing byproduct formation in industrial fermentations.

Authors+Show Affiliations

Kluyver Institute of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

10556793

Citation

Flikweert, M T., et al. "Steady-state and Transient-state Analysis of Growth and Metabolite Production in a Saccharomyces Cerevisiae Strain With Reduced Pyruvate-decarboxylase Activity." Biotechnology and Bioengineering, vol. 66, no. 1, 1999, pp. 42-50.
Flikweert MT, Kuyper M, van Maris AJ, et al. Steady-state and transient-state analysis of growth and metabolite production in a Saccharomyces cerevisiae strain with reduced pyruvate-decarboxylase activity. Biotechnol Bioeng. 1999;66(1):42-50.
Flikweert, M. T., Kuyper, M., van Maris, A. J., Kötter, P., van Dijken, J. P., & Pronk, J. T. (1999). Steady-state and transient-state analysis of growth and metabolite production in a Saccharomyces cerevisiae strain with reduced pyruvate-decarboxylase activity. Biotechnology and Bioengineering, 66(1), 42-50.
Flikweert MT, et al. Steady-state and Transient-state Analysis of Growth and Metabolite Production in a Saccharomyces Cerevisiae Strain With Reduced Pyruvate-decarboxylase Activity. Biotechnol Bioeng. 1999;66(1):42-50. PubMed PMID: 10556793.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Steady-state and transient-state analysis of growth and metabolite production in a Saccharomyces cerevisiae strain with reduced pyruvate-decarboxylase activity. AU - Flikweert,M T, AU - Kuyper,M, AU - van Maris,A J, AU - Kötter,P, AU - van Dijken,J P, AU - Pronk,J T, PY - 1999/11/11/pubmed PY - 1999/11/11/medline PY - 1999/11/11/entrez SP - 42 EP - 50 JF - Biotechnology and bioengineering JO - Biotechnol Bioeng VL - 66 IS - 1 N2 - Pyruvate decarboxylase is a key enzyme in the production of low-molecular-weight byproducts (ethanol, acetate) in biomass-directed applications of Saccharomyces cerevisiae. To investigate whether decreased expression levels of pyruvate decarboxylase can reduce byproduct formation, the PDC2 gene, which encodes a positive regulator of pyruvate-decarboxylase synthesis, was inactivated in the prototrophic strain S. cerevisiae CEN. PK113-7D. This caused a 3-4-fold reduction of pyruvate-decarboxylase activity in glucose-limited, aerobic chemostat cultures grown at a dilution rate of 0.10 h(-1). Upon exposure of such cultures to a 50 mM glucose pulse, ethanol and acetate were the major byproducts formed by the wild type. In the pdc2Delta strain, formation of ethanol and acetate was reduced by 60-70%. In contrast to the wild type, the pdc2Delta strain produced substantial amounts of pyruvate after a glucose pulse. Nevertheless, its overall byproduct formation was ca. 50% lower. The specific rate of glucose consumption after a glucose pulse to pdc2Delta cultures was about 40% lower than in wild-type cultures. This suggests that, at reduced pyruvate-decarboxylase activities, glycolytic flux is controlled by NADH reoxidation. In aerobic, glucose-limited chemostat cultures, the wild type exhibited a mixed respiro-fermentative metabolism at dilution rates above 0.30 h(-1). Below this dilution rate, sugar metabolism was respiratory. At dilution rates up to 0.20 h(-1), growth of the pdc2Delta strain was respiratory and biomass yields were similar to those of wild-type cultures. Above this dilution rate, washout occurred. The low micro(max) of the pdc2Delta strain in glucose-limited chemostat cultures indicates that occurrence of respiro-fermentative metabolism in wild-type cultures is not solely caused by competition of respiration and fermentation for pyruvate. Furthermore, it implies that inactivation of PDC2 is not a viable option for reducing byproduct formation in industrial fermentations. SN - 0006-3592 UR - https://www.unboundmedicine.com/medline/citation/10556793/Steady_state_and_transient_state_analysis_of_growth_and_metabolite_production_in_a_Saccharomyces_cerevisiae_strain_with_reduced_pyruvate_decarboxylase_activity_ L2 - https://doi.org/10.1002/(sici)1097-0290(1999)66:1<42::aid-bit4>3.0.co;2-l DB - PRIME DP - Unbound Medicine ER -