[Application of a metabolic-pathway-analysis based breeding strategy enhances the production of pyruvate by Torulopsis glabrata]

Wei Sheng Wu Xue Bao. 2005 Feb;45(1):77-80.
[Article in Chinese]

Abstract

To further enhance the pyruvate productivity by multi-vitamin auxotrophic yeast Torulopsis glabrata, a breeding strategy aiming at decreasing the activity of pyruvate decarboxylase but increasing the activity of acetyl-CoA synthetase was developed based on analysis of pyruvate-related metabolic pathways. Nitrosoguanidine mutagenized cells of T. glabrata WSH-IP303 were screened for mutants that require acetate for complete growth on glucose minimum medium. A mutant, T. glabrata CCTCC M202019, produced pyruvate 21% higher than that of the parent strain and was genetically stable in flask cultures, was selected as a working strain. To elucidate the metabolic changes that led to the increase of pyruvate production, the activities of enzymes that involved in pyruvate-related metabolic pathways of the mutant and the parent strain were determined. Enzymatic analysis revealed that, compared with the parent strain WSH-IP303, the activity of pyruvate decarboxylase of the mutant strain CCTCC M202019 decreased by roughly 40%, while the activity of acetyl-CoA synthetase of the latter increased by 103.5% or 57.4%, respectively, in the presence or absence of acetate. When 6 g/L sodium acetate was added to the medium, pyruvate production by the mutant strain CCTCC M202019 reached 68.7 g/L at 62 h (yield on glucose, 0.651 g/g) in fermentations performed in a 7-L jar fermentor, indicating the shortage of cytosolic acetyl-CoA resulted from the disruption of pyruvate decarboxylase was properly compensated by the increase of the activity of acetyl-CoA synthetase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / pharmacology
  • Candida glabrata / enzymology
  • Candida glabrata / genetics
  • Candida glabrata / growth & development
  • Candida glabrata / metabolism*
  • Coenzyme A Ligases / metabolism*
  • Culture Media / pharmacology
  • Fermentation
  • Mutagenesis
  • Pyruvate Decarboxylase / metabolism*
  • Pyruvic Acid / metabolism*

Substances

  • Acetates
  • Culture Media
  • Pyruvic Acid
  • Pyruvate Decarboxylase
  • Coenzyme A Ligases
  • acetate-CoA ligase (ADP-forming)