| 초록 |
Fumaric acid producing E. coli was developed by rational metabolic engineering strategies in this study. Firstly, the iclR gene was deleted to redirect the carbon flux through the glyoxylate shunt. In addition, the three known fumarase genes (fumA, fumB and fumC) were also deleted to enhance fumaric acid formation. This base strain was further engineered by plasmid-based overexpression of the native ppc gene. And then, the arcA and ptsG genes were sequentially deleted to reinforce the oxidative TCA cycle flux, and the aspA gene was deleted to block the conversion of fumaric acid into L-aspartic acid. Since it is desirable to avoid the use of inducer, the lacI gene was also deleted. The native promoter of the galP gene was replaced with the strong trc promoter to increase glucose uptake rate and fumaric acid productivity. Fed-batch culture of the final strain CWF812 allowed production of 28.2 g/L fumaric acid in 63 h with the overall yield and productivity of 0.389 g fumaric acid/g glucose and 0.448 g/L/h. (Development of systems metabolic engineering platform technologies for biorefineries; NRF-2012-C1AAA001-2012M1A2A2026556) funded by the Ministry of Education, Science and Technology) |
