| 초록 |
We engineered E.coli to synthesize GABA through knocking out byproduct pathway related genes and overexpressing modified glutamate decarboxylase which can synthesize GABA under neutral pH condition. However, as the titer of GABA was still low, 13C MFA was conducted to determine metabolic flux ratios of central carbon metabolism to identify metabolic bottleneck for GABA production. From 13C MFA result, intracellular metabolic flux ratios were successively quantified and rational metabolic engineering targets were determined. We enhanced anaplerotic flux by introducing heterologous pyruvate carboxylase from C. glutamicum and additionally down regulated TCA flux by knocking out sucA to reduce byproduct secretion by succinate. Finally, 13C MFA was carried out to verify optimal central carbon metabolic flux ratios for GABA production. Engineered E.coli strain synthesize 1.8 g/L of GABA in defined medium condition. |
