Metabolic Engineering Strategies to Produce Medium-chain Oleochemicals Via Acyl-ACP:CoA Transacylase Activity

Overview

Journal Nat Commun

Specialty Biology

Date 2022 Mar 26

PMID 35338129

Authors

Qiang Yan

William T Cordell

Michael A Jindra

Dylan K Courtney

Madeline K Kuckuk

Xuanqi Chen

Brian F Pfleger

Affiliations

Soon will be listed here.

Abstract

Microbial lipid metabolism is an attractive route for producing oleochemicals. The predominant strategy centers on heterologous thioesterases to synthesize desired chain-length fatty acids. To convert acids to oleochemicals (e.g., fatty alcohols, ketones), the narrowed fatty acid pool needs to be reactivated as coenzyme A thioesters at cost of one ATP per reactivation - an expense that could be saved if the acyl-chain was directly transferred from ACP- to CoA-thioester. Here, we demonstrate such an alternative acyl-transferase strategy by heterologous expression of PhaG, an enzyme first identified in Pseudomonads, that transfers 3-hydroxy acyl-chains between acyl-carrier protein and coenzyme A thioester forms for creating polyhydroxyalkanoate monomers. We use it to create a pool of acyl-CoA's that can be redirected to oleochemical products. Through bioprospecting, mutagenesis, and metabolic engineering, we develop three strains of Escherichia coli capable of producing over 1 g/L of medium-chain free fatty acids, fatty alcohols, and methyl ketones.

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