Replacing anaerobic fermentation with reverse β-oxidation enables growth-coupled evolution for enhanced fatty-alcohol production
Abstract
Engineering robust fermentation hosts remains a barrier to scalable biomanufacturing. In this work we replace canonical mixed-acid fermentation in Escherichia coli with a redox‑balanced reverse β‑oxidation (rBOX) pathway that produces medium‑chain fatty alcohols and is bioenergetically equivalent to ethanol fermentation. This synthetic fermentation restores anaerobic growth, tightly coupling fitness to product formation and enabling adaptive laboratory evolution that selects for mutations increasing rBOX flux. Evolved strains increase maximum productivity fourfold (110 ± 0.15 mg/L/hr) and titer more than threefold up to 4.0 ± 0.28 g/L compared to the unevolved strain. Proteomic analyses of evolved strains indicate differential expression of enzymes at key metabolic nodes and activation of latent genes with functions overlapping those of rBOX enzymes. These results establish redox-balanced growth coupling as a powerful tool for strain improvement and demonstrate rBOX as a practical synthetic fermentation pathway.
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BibTeX
@article{cawthon2026replacing,
title = {{Replacing anaerobic fermentation with reverse β-oxidation enables growth-coupled evolution for enhanced fatty-alcohol production}},
author = {Bridgie Cawthon and Aidan E. Cowan and Zen Yoshikawa and Kenneth Low and Justin Baerwald and Nawa Raj Baral and Matthew Incha and Jennifer Gin and Yan Chen and Christopher J. Petzold and Edward E. K. Baidoo and Emine A. Turumtay and Corinne D. Scown and Adam M. Feist and Jay D. Keasling},
journal = {Nature Communications},
year = {2026},
month = oct,
doi = {10.1038/s41467-026-78481-1},
url = {https://www.nature.com/articles/s41467-026-78481-1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Replacing anaerobic fermentation with reverse β-oxidation enables growth-coupled evolution for enhanced fatty-alcohol production
AU - Bridgie Cawthon
AU - Aidan E. Cowan
AU - Zen Yoshikawa
AU - Kenneth Low
AU - Justin Baerwald
AU - Nawa Raj Baral
AU - Matthew Incha
AU - Jennifer Gin
AU - Yan Chen
AU - Christopher J. Petzold
AU - Edward E. K. Baidoo
AU - Emine A. Turumtay
AU - Corinne D. Scown
AU - Adam M. Feist
AU - Jay D. Keasling
PY - 2026
DA - 2026/10/14
JO - Nature Communications
DO - 10.1038/s41467-026-78481-1
UR - https://www.nature.com/articles/s41467-026-78481-1
AB - Engineering robust fermentation hosts remains a barrier to scalable biomanufacturing. In this work we replace canonical mixed-acid fermentation in Escherichia coli with a redox‑balanced reverse β‑oxidation (rBOX) pathway that produces medium‑chain fatty alcohols and is bioenergetically equivalent to ethanol fermentation. This synthetic fermentation restores anaerobic growth, tightly coupling fitness to product formation and enabling adaptive laboratory evolution that selects for mutations increasing rBOX flux. Evolved strains increase maximum productivity fourfold (110 ± 0.15 mg/L/hr) and titer more than threefold up to 4.0 ± 0.28 g/L compared to the unevolved strain. Proteomic analyses of evolved strains indicate differential expression of enzymes at key metabolic nodes and activation of latent genes with functions overlapping those of rBOX enzymes. These results establish redox-balanced growth coupling as a powerful tool for strain improvement and demonstrate rBOX as a practical synthetic fermentation pathway.
SN - 2041-1723
ER -