Regulation of thiamine synthesis in Saccharomyces cerevisiae for improved pyruvate production.
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-002ΔTHI2 and FMME-002ΔTHI3 both exhibited an enhanced pyruvate yield. Moreover, FMME-002ΔTHI2 achieved a relatively higher pyruvate production, and the highest concentration of pyruvate was achieved when 0.04 µ 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-002ΔTHI2 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.
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China.
Guoqiang
G
Xu
Qiang
Q
Hua
Ningjun
N
Duan
Liming
L
Liu
Jian
J
Chen
D004798:Enzymes / Q000235:genetics / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism; D005285:Fermentation; D015966:Gene Expression Regulation, Fungal; D055786:Gene Knockout Techniques; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways / Q000235:genetics; D008954:Models, Biological; D019289:Pyruvic Acid / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D013831:Thiamine / Q000096:biosynthesis*
D004798:Enzymes; D029701:Saccharomyces cerevisiae Proteins; D000431:Ethanol; D019289:Pyruvic Acid; D013831:Thiamine