Production of Hexanoic Acid from Long Chain Fatty Acid in Escherichia coli

Abstract

All over the world, the efforts are under way to find the petroleum replacement resources in order to overcome fossil fuel depletion and to reduce greenhouse-gas emissions. In this respect, replacing petrochemicals with renewable alternatives is one of the principal challenges of our day. Hexanoic acid could be widely used as a precursor to biofuels and for the production of chain based chemicals such as adipic acid, hexane, amino-caproic acid and so on. In order to produce specific carbon chain fatty acid, Escherichia coli β-oxidation pathway was engineered. First, fadE and fadR genes were deleted. And then, E. coli acyl-CoA dehydrogenase (FadE) was replaced with acyl-CoA oxidase 2 encoded by POX2 gene from Yarrowia lipolytica, which has substrate specificity towards medium to long chain fatty acyl-CoA. Finally the thioesteraseⅡ (TesB) was overexpressed in the cell. In this study, a maximum of 210mg/L of hexanoic acid was produced by the engineered strain (MGREBA2) from 1g/L of oleic acid in 48hours of biotransformation. Based on these results, it is suggested that various oil as feedstock will be directly applied for the production of short chain fatty acids, especially hexanoic acid.