초록
<P><B>Abstract</B></P><P>Metabolic engineering of <I>Saccharomyces cerevisiae</I> 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, <I>THI2</I> and <I>THI3</I>, were disrupted in the <I>S. cerevisiae</I> parent strain FMME‐002. The mutants FMME‐002<I>ΔTHI2</I> and FMME‐002<I>ΔTHI3</I> both exhibited an enhanced pyruvate yield. Moreover, FMME‐002<I>ΔTHI2</I> achieved a relatively higher pyruvate production, and the highest concentration of pyruvate was achieved when 0.04 µ <SMALL>m</SMALL> thiamine was added. Enzyme assays and fermentation profiles of the <I>THI2</I>‐complemented strain indicated that the observed metabolic changes represented intrinsic effects of <I>THI2</I> deletion on the physiology of <I>S. cerevisiae</I>. Under optimal C:N ratio conditions, FMME‐002<I>ΔTHI2</I> 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 <I>S. cerevisiae</I>. Copyright © 2012 John Wiley & Sons, Ltd.</P>