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Design of a dynamic sensor-regulator system for production of chemicals and fuels derived from fatty acids

Abstract

Microbial production of chemicals is now an attractive alternative to chemical synthesis. Current efforts focus mainly on constructing pathways to produce different types of molecules1,2,3. However, there are few strategies for engineering regulatory components to improve product titers and conversion yields of heterologous pathways4. Here we developed a dynamic sensor-regulator system (DSRS) to produce fatty acid–based products in Escherichia coli, and demonstrated its use for biodiesel production. The DSRS uses a transcription factor that senses a key intermediate and dynamically regulates the expression of genes involved in biodiesel production. This DSRS substantially improved the stability of biodiesel-producing strains and increased the titer to 1.5 g/l and the yield threefold to 28% of the theoretical maximum. Given the large number of natural sensors available, this DSRS strategy can be extended to many other biosynthetic pathways to balance metabolism, thereby increasing product titers and conversion yields and stabilizing production hosts.

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Figure 1: Design of FA/acyl-CoA biosensors.
Figure 2: Hybrid FA/acyl-CoA–regulated promoters.
Figure 3: Regulation of FAEE production by the DSRS.
Figure 4: Metabolite analysis and dynamic behavior of FAEE-producing strains.

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Acknowledgements

The authors would like to thank W. Holtz, E. Steen and N. Hillson for discussion and critical reading of the manuscript. This work was supported in part by the Synthetic Biology Engineering Research Center, which is funded by National Science Foundation award no. 0540879, and by the Joint BioEnergy Institute, which is funded by the US Department of Energy, Office of Science, Office of Biological and Environmental Research, through contract DE-AC02-05CH11231. F.Z. is supported by the Postdoctoral Fellowships Program of the Natural Sciences and Engineering Research Council of Canada.

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Authors

Contributions

F.Z. and J.D.K. conceived the project and designed the experiments. F.Z. performed the experiments. J.M.C. designed and performed the DSRS modeling. F.Z., J.M.C. and J.D.K. analyzed the data and wrote the paper.

Corresponding author

Correspondence to Jay D Keasling.

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Competing interests

J.D.K. has a financial interest in Amyris, LS9 and Lygos.

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Supplementary Tables 1–5 and Supplementary Figures 1–9 (PDF 860 kb)

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Zhang, F., Carothers, J. & Keasling, J. Design of a dynamic sensor-regulator system for production of chemicals and fuels derived from fatty acids. Nat Biotechnol 30, 354–359 (2012). https://doi.org/10.1038/nbt.2149

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