In yeast, pyruvate is placed at the crossroad of fermentation, oxidative metabolism and anabolic pathways. In this study we have characterized a previously developed pyruvate undersecreting sake yeast obtained by isolating a strain (TCR7) tolerant to ethyl α-transcyanocinnamate, an inhibitor of pyruvate transport into mitochondria. To obtain insights into pyruvate metabolism, we investigated the mitochondrial activity of TCR7 by oxigraphy and 13C-metabolic flux analysis. The mutant strain (TCR7), displayed an higher mitochondrial pyruvate influx and oxidation, and a decreased glycerol production compared to the reference strain. These results indicate that mitochondrial activity is elevated in the TCR7 strain with the consequence of decreased pyruvate extracellular secretion. Surprisingly mitochondrial activity resulted much higher in the sake yeast compared to CEN.PK 113-7D, the reference strain employied in metabolic engineering. When shifted from aerobic to anaerobic conditions, sake yeast retained a branched mitochondrial structure for a longer time than laboratory strains. Further studies are needed to unveil the molecular mechanisms underlying these phenotypes.

Increased mitochondrial pyruvate dissimilation in yeast

AGRIMI, GENNARO;PISANO, ISABELLA;
2014-01-01

Abstract

In yeast, pyruvate is placed at the crossroad of fermentation, oxidative metabolism and anabolic pathways. In this study we have characterized a previously developed pyruvate undersecreting sake yeast obtained by isolating a strain (TCR7) tolerant to ethyl α-transcyanocinnamate, an inhibitor of pyruvate transport into mitochondria. To obtain insights into pyruvate metabolism, we investigated the mitochondrial activity of TCR7 by oxigraphy and 13C-metabolic flux analysis. The mutant strain (TCR7), displayed an higher mitochondrial pyruvate influx and oxidation, and a decreased glycerol production compared to the reference strain. These results indicate that mitochondrial activity is elevated in the TCR7 strain with the consequence of decreased pyruvate extracellular secretion. Surprisingly mitochondrial activity resulted much higher in the sake yeast compared to CEN.PK 113-7D, the reference strain employied in metabolic engineering. When shifted from aerobic to anaerobic conditions, sake yeast retained a branched mitochondrial structure for a longer time than laboratory strains. Further studies are needed to unveil the molecular mechanisms underlying these phenotypes.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/94345
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