Production of gamma-aminobutyric acid from glucose by introduction of synthetic scaffolds between isocitrate dehydrogenase, glutamate synthase and glutamate decarboxylase in recombinant Escherichia coli

Escherichia coli were engineered for the direct production of gamma-aminobutyric acid from glucose by introduction of synthetic protein scaffold. In this study, three enzymes consisting GABA pathway (isocitrate dehydrogenase, glutamate synthase and glutamate decarboxylase) were connected via synthetic protein scaffold. By introduction of scaffold, 0.92 g/L of GABA was produced from 10 g/L of glucose while no GABA was produced in wild type E. coli. The optimum pH and temperature for GABA production were 4.5 and 30 °C, respectively. When competing metabolic network was inactivated by knockout mutation, maximum GABA concentration of 1.3 g/L was obtained from 10 g/L glucose. The recombinant E. coli strain which produces GABA directly from glucose was successfully constructed by introduction of protein scaffold.