Bioprocess and Biosystems Engineering

, Volume 33, Issue 7, pp 873–883

Studies on substrate utilisation in l-valine-producing Corynebacterium glutamicum strains deficient in pyruvate dehydrogenase complex

  • Tobias Bartek
  • Christiane Rudolf
  • Ulrike Kerßen
  • Bianca Klein
  • Bastian Blombach
  • Siegmund Lang
  • Bernhard J. Eikmanns
  • Marco Oldiges
Original Paper

DOI: 10.1007/s00449-010-0410-1

Cite this article as:
Bartek, T., Rudolf, C., Kerßen, U. et al. Bioprocess Biosyst Eng (2010) 33: 873. doi:10.1007/s00449-010-0410-1

Abstract

The pyruvate dehydrogenase complex was deleted to increase precursor availability in Corynebacterium glutamicum strains overproducing l-valine. The resulting auxotrophy is treated by adding acetate in addition glucose for growth, resulting in the puzzling fact of gluconeogenic growth with strongly reduced glucose uptake in the presence of acetate in the medium. This result was proven by intracellular metabolite analysis and labelling experiments. To increase productivity, the SugR protein involved in negative regulation of the phosphotransferase system, was inactivated, resulting in enhanced consumption of glucose. However, the surplus in substrate uptake was not converted to l-valine; instead, the formation of up to 289 μM xylulose was observed for the first time in C. glutamicum. As an alternative to the genetic engineering solution, a straightforward process engineering approach is proposed. Acetate limitation resulted in a more efficient use of acetate as cosubstrate, shown by an increased biomass yield YX/Ac and improved l-valine formation.

Keywords

Corynebacterium glutamicuml-ValinePyruvate dehydrogenase complexSubstrate uptakeFermentation process developmentXylulose

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Tobias Bartek
    • 1
    • 4
  • Christiane Rudolf
    • 1
  • Ulrike Kerßen
    • 1
  • Bianca Klein
    • 1
  • Bastian Blombach
    • 2
  • Siegmund Lang
    • 3
  • Bernhard J. Eikmanns
    • 2
  • Marco Oldiges
    • 1
  1. 1.Institute of Biotechnology 2Forschungszentrum JülichJülichGermany
  2. 2.Institute of Microbiology and BiotechnologyUniversity of UlmUlmGermany
  3. 3.Institute for Biochemistry and BiotechnologyBraunschweig University of TechnologyBraunschweigGermany
  4. 4.Lonza BiopharmaceuticalsR&D Microbial Services, Lonza AGVispSwitzerland