Repression of mitochondrial metabolism for cytosolic pyruvate-derived chemical production in Saccharomyces cerevisiae.
BACKGROUND
Saccharomyces cerevisiae is a suitable host for the industrial production of pyruvate-derived chemicals such as ethanol and 2,3-butanediol (23BD). For the improvement of the productivity of these chemicals, it is essential to suppress the unnecessary pyruvate consumption in S. cerevisiae to redirect the metabolic flux toward the target chemical production. In this study, mitochondrial pyruvate transporter gene (MPC1) or the essential gene for mitophagy (ATG32) was knocked-out to repress the mitochondrial metabolism and improve the production of pyruvate-derived chemical in S. cerevisiae.


RESULTS
The growth rates of both aforementioned strains were 1.6-fold higher than that of the control strain. 13C-metabolic flux analysis revealed that both strains presented similar flux distributions and successfully decreased the tricarboxylic acid cycle fluxes by 50% compared to the control strain. Nevertheless, the intracellular metabolite pool sizes were completely different, suggesting distinct metabolic effects of gene knockouts in both strains. This difference was also observed in the test-tube culture for 23BD production. Knockout of ATG32 revealed a 23.6-fold increase in 23BD titer (557.0 ± 20.6 mg/L) compared to the control strain (23.5 ± 12.8 mg/L), whereas the knockout of MPC1 revealed only 14.3-fold increase (336.4 ± 113.5 mg/L). Further investigation using the anaerobic high-density fermentation test revealed that the MPC1 knockout was more effective for ethanol production than the 23BD production.


CONCLUSION
These results suggest that the engineering of the mitochondrial transporters and membrane dynamics were effective in controlling the mitochondrial metabolism to improve the productivities of chemicals in yeast cytosol.
['Morita|Keisuke|K|', 'Matsuda|Fumio|F|', 'Okamoto|Koji|K|', 'Ishii|Jun|J|', 'Kondo|Akihiko|A|', 'Shimizu|Hiroshi|H|']
D000071183:Autophagy-Related Proteins D002072:Butylene Glycols D003600:Cytosol D000431:Ethanol D005285:Fermentation D008565:Membrane Proteins D060847:Metabolic Engineering D008928:Mitochondria D017853:Phosphotransferases (Alcohol Group Acceptor) D019289:Pyruvic Acid D018160:Receptors, Cytoplasmic and Nuclear D012441:Saccharomyces cerevisiae D029701:Saccharomyces cerevisiae Proteins
Saccharomyces cerevisiae 2,3-Butanediol Mitophagy 13C-metabolic flux analysis Metabolome Mitochondrial pyruvate carrier