Layered dynamic regulation for improving metabolic pathway productivity in Escherichia coli
Name
2964.full.pdf
Size
849 KB
Format
Adobe PDF
Checksum (MD5)
f33c0dae5668b6f31feec515ffe9af9b
Author(s)
Doong, Stephanie
Gupta, Apoorv
Jones, Kristala L.
Date Issued
March 2018
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Citation
Doong, Stephanie J., Apoorv Gupta, and Kristala L. J. Prather. “Layered Dynamic Regulation for Improving Metabolic Pathway Productivity in Escherichia Coli.” Proceedings of the National Academy of Sciences 115, no. 12 (March 5, 2018): 2964–2969. © 2018 National Academy of Sciences.
Version
Final published version
Abstract
Microbial production of value-added chemicals from biomass is a sustainable alternative to chemical synthesis. To improve product titer, yield, and selectivity, the pathways engineered into microbes must be optimized. One strategy for optimization is dynamic pathway regulation, which modulates expression of pathwayrelevant enzymes over the course of fermentation. Metabolic engineers have used dynamic regulation to redirect endogenous flux toward product formation, balance the production and consumption rates of key intermediates, and suppress production of toxic intermediates until later in the fermentation. Most cases, however, have utilized a single strategy for dynamically regulating pathway fluxes. Here we layer two orthogonal, autonomous, and tunable dynamic regulation strategies to independently modulate expression of two different enzymes to improve production of D-glucaric acid from a heterologous pathway. The first strategy uses a previously described pathway-independent quorum sensing system to dynamically knock down glycolytic flux and redirect carbon into production of glucaric acid, thereby switching cells from "growth" to "production" mode. The second strategy, developed in this work, uses a biosensor for myo-inositol (MI), an intermediate in the glucaric acid production pathway, to induce expression of a downstream enzyme upon sufficient buildup of MI. The latter, pathway-dependent strategy leads to a 2.5-fold increase in titer when used in isolation and a fourfold increase when added to a strain employing the former, pathway-independent regulatory system. The dual-regulation strain produces nearly 2 g/L glucaric acid, representing the highest glucaric acid titer reported to date in Escherichia coli K-12 strains.
MIT Department
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Chemical Engineering
Massachusetts Institute of Technology. Synthetic Biology Center
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1073/PNAS.1716920115
