Increasing glycolytic flux in Torulopsis glabrata by redirecting ATP production from oxidative phosphorylation to substrate-level phosphorylation.
Abstract Aims: This study aimed at further increasing the pyruvate productivity of a multi-vitamin auxotrophic yeast Torulopsis glabrata by redirecting ATP production from oxidative phosphorylation to substrate-level phosphorylation. Methods and Results: We examined two strategies to decrease the activity of F(0)F(1)-ATPase. The strategies were to inhibit F(0)F(1)-ATPase activity by addition of oligomycin, or to disrupt F(0)F(1)-ATPase by screening neomycin-resistant mutant. The addition of 0.05 mmol l(-1) oligomycin to the culture broth of T. glabrata CCTCC M202019 resulted in a significantly decreased intracellular ATP level (35.7%) and a significantly increased glucose consumption rate (49.7%). A neomycin-resistant mutant N07 was screened and selected after nitrosoguanidine mutagenesis of the parent strain T. glabrata CCTCC M202019. Compared with the parent strain, the F(0)F(1)-ATPase activity of the mutant N07 decreased about 65%. As a consequence, intracellular ATP level of the mutant N07 decreased by 24%, which resulted in a decreased growth rate and growth yield. As expected, glucose consumption rate and pyruvate productivity of the mutant N07 increased by 34% and 42.9%, respectively. Consistently, the activities of key glycolytic enzymes of the mutant N07, including phosphofructokinase, pyruvate kinase and glyceraldyde-3-phosphate dehydrogenase, increased by 63.7%, 28.8% and 14.4%, respectively. In addition, activities of the key enzymes involved in electron transfer chain of the mutant N07 also increased. Conclusions: Impaired oxidative phosphorylation in T. glabrata leads to a decreased intracellular ATP production, thereby increasing the glycolytic flux. Significance and Impact of the Study: The strategy of redirecting ATP production from oxidative phosphorylation to substrate-level phosphorylation provides an alternative approach to enhance the glycolytic flux in eukaryotic micro-organisms.[1]References
- Increasing glycolytic flux in Torulopsis glabrata by redirecting ATP production from oxidative phosphorylation to substrate-level phosphorylation. Liu, L.M., Li, Y., Du, G.C., Chen, J. J. Appl. Microbiol. (2006) [Pubmed]
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