Expanding Upon Styrene Biosynthesis to Engineer a Novel Route to 2‐Phenylethanol. Issue 10 (4th September 2017)

• Record Type: Journal Article
• Authors: Machas, Michael S.; McKenna, Rebekah; Nielsen, David R.
• Is Part Of: Biotechnology journal. Volume 12:Issue 10(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-09-04
• Subjects: 2‐phenylethanol -- aromatics -- L‐phenylalanine -- styrene -- styrene oxide; Biotechnology -- Periodicals; 660.605
• DOI: 10.1002/biot.201700310
• Languages: English
• ISSNs: 1860-6768

Abstract

Abstract : 2‐Phenylethanol (2PE) is a key molecule used in the fragrance and food industries, as well as a potential biofuel. In contrast to its extraction from plant biomass and/or more common chemical synthesis, microbial 2PE production has been demonstrated via both native and heterologous expression of the yeast Ehrlich pathway. Here, a novel alternative to this established pathway is systematically engineered in Escherichia coli and evaluated as a more robust and efficient route. This novel pathway is constructed via the modular extension of a previously engineered styrene biosynthesis pathway, proceeding from endogenous l ‐phenylalanine in five steps and involving four heterologous enzymes. This "styrene‐derived" pathway boasts nearly a 10‐fold greater thermodynamic driving force than the Ehrlich pathway, and enables reduced accumulation of acetate byproduct. When directly compared using a host strain engineered for l ‐phenylalanine over‐production, preservation of phosphoenolpyruvate, and reduced formation of byproduct 2‐phenylacetic acid, final 2PE titers via the styrene‐derived and Ehrlich pathways reached 1817 and 1164 mg L −1, respectively, at yields of 60.6 and 38.8 mg g −1 . Following optimization of induction timing and initial glucose loading, 2PE titers by the styrene‐derived pathway approached 2 g L −1 – nearly a two‐fold twofold increase over prior reports for 2PE production by E. coli employing the Ehrlich pathway. Abstract : The aromatic alcohol 2‐phenylethanol (2PE) is a key molecule used in the fragrance and food industries as well as a potential biofuel. In contrast to its traditional extraction from plant biomass and/or more common chemical synthesis, microbial 2PE production is also demonstrated via the yeast Ehrlich pathway. In this study, the authors systematically engineer a novel, "styrene‐derived" 2PE pathway as a more robust and efficient alternative to the established Ehrlich pathway, demonstrating significant titer and yield enhancements as a result.