Metabolic Engineering of Escherichia coli for Production of 2-Phenylethanol and 2-Phenylethyl Acetate from Glucose

Rose-like odor 2-phenylethanol (2-PE) and its more fruit-like ester 2-phenylethyl acetate (2-PEAc) are two important aromatic compounds and have wide applications. In the past, 2-PE and 2-PEAc were mainly produced from l-phenylalanine. In this study, Escherichia coli was engineered to de novo biosynthesis of 2-PE and 2-PEAc from glucose: first, overexpression of deregulated 3-deoxy-d-arabinoheptulosonate-7-phosphate synthase aroG fbr and chorismate mutase/prephenate dehydratase pheA fbr for increasing phenylpyruvate production in E. coli, subsequently, heterologous expression of decarboxylase kdc and overexpression of reductase yjgB for the conversion of phenylpyruvate to 2-PE, with the engineered strain DG01 producing 578 mg/L 2-PE, and, finally, heterologous expression of an aminotransferase aro8 to redirect the metabolic flux to phenylpyruvate. 2-PE (1016 mg/L) was accumulated in the engineered strain DG02. Alcohol acetyltransferase ATF1 from Saccharomyces cerevisiae can esterify a wide variety of alcohols, including 2-PE. We have further demonstrated the biosynthesis of 2-PEAc from glucose by overexpressing atf1 for the subsequent conversion of 2-PE to 2-PEAc. The engineered strain DG03 produced 687 mg/L 2-PEAc.