Production of Natural 2‑Phenylethanol from Glucose or Glycerol with Coupled Escherichia coli Strains Expressing l‑Phenylalanine Biosynthesis Pathway and Artificial Biocascades

• Published in: ACS sustainable chemistry & engineering 2019-07, Vol.7 (14), p.12231-12239, Article acssuschemeng.9b01569
• Main Authors: Sekar, Balaji Sundara, Lukito, Benedict Ryan, Li, Zhi
• Format: Article
• Language: English
• ISSN: 2168-0485; 2168-0485
• DOI: 10.1021/acssuschemeng.9b01569

2-Phenylethanol (2-PE) is a fragrance widely used in food and cosmetics. Natural 2-PE is preferred in these applications but with high price and very limited availability. Microbial synthesis from glucose or glycerol is an attractive way to produce natural 2-PE, but suffers from low product titer. Escherichia coli NST74-Phe-Sty was engineered to coexpress the l-phenylalanine (l-Phe) biosynthesis pathway and enzyme cascade of l-Phe to 2-PE, producing only 0–0.17 g/L 2-PE from glucose at 22–37 °C due to the incompatibility of the temperature for enzyme expression and activity. Enhanced production of 2-PE (8.4–9.1 g/L) from glucose or glycerol was achieved by coupling of E. coli NST74-Phe expressing the l-Phe biosynthesis pathway for l-Phe production at the optimal temperature of 37 °C with E. coli T7-Sty expressing enzyme cascades of l-Phe to 2-PE at the optimal expression temperature of 22 °C and the optimal biotransformation temperature of 30 °C. The 2-PE titer is 4.7-fold higher than the best reported 2-PE concentration produced from glucose. The coupled strains approach could be generally applicable for enhancing microbial production of useful chemicals from sugars or glycerol.