Metabolic engineering of Escherichia coli for production of 2‐Phenylethylacetate from L‐phenylalanine

Abstract

In order to meet the need of consumer preferences for natural flavor compounds, microbial synthesis method has become a very attractive alternative to the chemical production. The 2‐phenylethanol (2‐PE) and its ester 2‐phenylethylacetate (2‐PEAc) are two extremely important flavor compounds with a rose‐like odor. In recent years, Escherichia coli and yeast have been metabolically engineered to produce 2‐PE. However, a metabolic engineering approach for 2‐PEAc production is rare. Here, we designed and expressed a 2‐PEAc biosynthetic pathway in E. coli. This pathway comprised four steps: aminotransferase (ARO8) for transamination of L‐phenylalanine to phenylpyruvate, 2‐keto acid decarboxylase KDC for the decarboxylation of the phenylpyruvate to phenylacetaldehyde, aldehyde reductase YjgB for the reduction of phenylacetaldehyde to 2‐PE, alcohol acetyltransferase ATF1 for the esterification of 2‐PE to 2‐PEAc. Using the engineered E. coli strain for shake flasks cultivation with 1 g/L L‐phenylalanine, we achieved co‐production of 268 mg/L 2‐PEAc and 277 mg/L 2‐PE. Our results suggest that approximately 65% of L‐phenylalanine was utilized toward 2‐PEAc and 2‐PE biosynthesis and thus demonstrate potential industrial applicability of this microbial platform.

Escherichia coli as a host for metabolic engineering

“…268 mg/L from phenylalanine feeding Combined the synthesis pathway of 2-phenylethanol from phenylalanine and ester formation using alcohol transferase ATF1 (Guo et al, 2017).…”

Innovative Production of Bioproducts From Organic Waste Through Solid-State Fermentation

“…Another interesting bioproduct produced by SSF are aroma compounds. One of the most used aroma compounds are roselike scented 2-phenethyl alcohol (2-PE) (Stark et al, 2003) and the floral fragrance 2-phenethyl acetate (2-PEA) (Guo et al, 2017). Martinez-Ávila et al (2017Martinez-Ávila et al ( , 2018 reported a residuebased productive process to obtain fruit-like aromas using Kluyveromyces marxianus and sugarcane bagasse via SSF.…”

Generation of Flavors and Fragrances Through Biotransformation and De Novo Synthesis

“…One of the most relevant flavor-alcohols is the 2-PE, an aromatic alcohol with a delicate fragrance of rose petals (Burdock 2010) widely applied in diverse types of products, such as perfumes, cosmetics, pharmaceuticals, foods, and beverages (Carlquist et al 2015). Furthermore, 2-PE can be used as raw material to produce other important flavor compounds, such as 2-phenylethylacetate (a high-value aromatic ester (Etschmann et al 2002) and a potential fuel molecule (Kang et al 2014), phenylacetaldehyde (flavor compound), and phydroxphenylethanol (used in pharmaceutical and fine chemical industries) (Guo et al 2017). The economic importance of 2-PE is quite significant; in 1990 it was reported that the 2-PE global market was estimated at 7000 tones, with 6000 tons used for fragrances, 10 tons for flavor applications, and 990 tons for synthesis of reaction products like esters (Etschmann et al 2002).…”

“…Since yeasts are good candidates for 2-PE production from L-Phe bioconversion, considerable progresses have been achieved by applying different metabolic engineering strategies of related pathways (Guo et al 2017;Kang et al 2014;Wang et al 2017). In yeasts, several genes are involved in the catabolism of L-Phe to 2-PE via Ehrlich pathway.…”

“…These studies demonstrated the improvement of 2-PE production by overexpression of key enzymes in the Ehrlich pathway, providing new perspectives to enhance Bnatural^2-PE production. Using an engineered E. coli strain, Guo et al (2017) achieved a 2-PE production of 0.28 g L −1 .…”