Metabolic engineering of Saccharomyces cerevisiae for high-yield production of carboxylic acid requires a cytosolic pyruvate pool as precursor. In this study, a novel strategy to improve pyruvate production and reduce metabolic by-products via regulating thiamine synthesis was explored. Two of the thiamine biosynthesis regulatory genes, THI2 and THI3, were disrupted in the S. cerevisiae parent strain FMME-002. The mutants FMME-002DeltaTHI2 and FMME-002DeltaTHI3 both exhibited an enhanced pyruvate yield. Moreover, FMME-002DeltaTHI2 achieved a relatively higher pyruvate production, and the highest concentration of pyruvate was achieved when 0.04 micro m thiamine was added. Enzyme assays and fermentation profiles of the THI2-complemented strain indicated that the observed metabolic changes represented intrinsic effects of THI2 deletion on the physiology of S. cerevisiae. Under optimal C:N ratio conditions, FMME-002DeltaTHI2 produced pyruvate up to 8.21 +/- 0.30 g/l, whereas the ethanol titre decreased to 2.21 +/- 0.24 g/l after 96 h of cultivation. These results demonstrate the possibility of improving pyruvate production by regulating thiamine synthesis in S. cerevisiae. Copyright (c) 2012 John Wiley & Sons, Ltd.CI - Copyright (c) 2012 John Wiley & Sons, Ltd.
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