The utilization of edible biomass, such as corn and sugarcane as a feedstock for production of chemicals and biofuels greatly affects the food supply as well as the cost of food production. In order to address the ‘food versus chemical’ issue, we utilized D-xylose and L-arabinose sugars present abundantly in lignocellulosic biomass or the non-edible biomass to produce a valuable chemical product, specifically gamma-aminobutyric acid (GABA). GABA is a four-carbon amino acid commonly used for food production, such as gammalone and cheese, as well as an inhibitory neurotransmitter in mammalian brain. GABA is also used for the production of nylon 4, a thermally stable and biodegradable polymer that has been developed in the last few decades.
In order to synthesize GABA, we used the non-phosphorylative ‘shortcut’ pathway that was recently developed in the Zhang lab in the Chemical Engineering Department at the University of Minnesota to produce alpha-ketoglutarate (2-KG), an intermediate of GABA production from D-xylose and L-arabinose. This pathway has fewer steps and is more efficient than the traditional glycolysis pathway. Therefore, we engineered this biosynthetic pathway to produce GABA from both D-xylose and L-arabinose sugars in recombinant E. coli. We managed to produce 0.69 g/L and 0.81 g/L GABA from initial D-xylose and L-arabinose concentrations of 20 g/L respectively.
This research was supported by the Undergraduate Research Opportunities Program (UROP).
Engineering Non-Phosphorylative Metabolism in Escherichia coli for Production of Gamma-Aminobutyric Acid (GABA) from D-Xylose and L-Arabinose.
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