About this item:

424 Views | 367 Downloads

Author Notes:

Correspondence: Ichiro Matsumura; Email: imatsum@emory.edu

Author Contributions: Conceived and designed the experiments: IM.

Performed the experiments: AW and KF.

Analyzed the data: IM, KF and AB.

Contributed reagents/materials/analysis tools: AB.

Wrote the paper: IM and KF.

Acknowledgments: We thank Prof. Susan Gilbert for teaching IM about the Production Possibilities Frontier model, and others in the Matsumura lab for their helpful suggestions.

Disclosures: The authors have declared that no competing interests exist.

Subjects:

Research Funding:

This work was supported by the National Science Foundation. KF and IM were supported by grant number EF-1104988 (NSF3)

AB, AW and IM were supported by MCB-0951076 (NSF2)

Escherichia coli Deletion Mutants Illuminate Trade-Offs between Growth Rate and Flux through a Foreign Anabolic Pathway

Tools:

Journal Title:

PLoS ONE

Volume:

Volume 9, Number 2

Publisher:

, Pages e88159-e88159

Type of Work:

Article | Final Publisher PDF

Abstract:

Metabolic engineers strive to improve the production yields of microbial fermentations, sometimes by mutating the genomes of production strains. Some mutations are detrimental to the health of the organism, so a quantitative and mechanistic understanding of the trade-offs could inform better designs. We employed the bacterial luciferase operon (luxABCDE), which uses ubiquitous energetic cofactors (NADPH, ATP, FMNH2, acetyl-CoA) from the host cell, as a proxy for a novel anabolic pathway. The strains in the Escherichia coli Keio collection, each of which contains a single deletion of a non-essential gene, represent mutational choices that an engineer might make to optimize fermentation yields. The Keio strains and the parental BW25113 strain were transformed with a luxABCDE expression vector. Each transformant was propagated in defined M9 medium at 37°C for 48 hours; the cell density (optical density at 600 nanometers, OD600) and luminescence were measured every 30 minutes. The trade-offs were visualized by plotting the maximum growth rate and luminescence/OD600 of each transformant across a “production possibility frontier”. Our results show that some loss-of-function mutations enhance growth in vitro or light production, but that improvement in one trait generally comes at the expense of the other.

Copyright information:

© 2014 Falls et al.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
Export to EndNote