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Triggering the stringent response enhances synthetic methanol utilization in Escherichia coli
R Kyle Bennett1, Alec Agee1, Jie Ren Gerald Har2
1Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, USA; The Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
Metabolic Engineering
|May 4, 2020
Summary
Synthetic methylotrophy enables engineering microbes like E. coli to use methane or methanol. Activating the stringent/stress response improves amino acid biosynthesis, a key step towards autonomous methylotrophy.
Area of Science:
- Synthetic biology
- Microbial engineering
- Metabolic engineering
Background:
- Synthetic methylotrophy aims to engineer microbes for utilizing methane and methanol.
- Autonomous methylotrophy, using these compounds as sole carbon/energy sources, remains unrealized.
- A key limitation in E. coli is its inability to synthesize essential amino acids when grown on methanol.
Purpose of the Study:
- To overcome the limitation of amino acid biosynthesis in methanol-grown E. coli.
- To enhance autonomous methylotrophy in synthetic methylotrophs.
- To investigate the role of the stringent/stress response in supporting methylotrophic growth.
Main Methods:
- Engineered E. coli strains by activating the stringent/stress response.
- Utilized ppGpp overproduction, DksA, and RpoS overexpression.
- Analyzed the endogenous upregulation of amino acid synthesis pathway genes.
Main Results:
- Demonstrated improved biosynthesis of proteinogenic amino acids from methanol-derived carbon.
- Achieved biosynthesis of several limiting amino acids, unlike control strains.
- Showcased the alleviation of a key limitation for autonomous methylotrophy.
Conclusions:
- Activation of the stringent/stress response is crucial for autonomous methylotrophy in E. coli.
- This approach enables essential amino acid synthesis from methanol.
- Provides a strategy to advance synthetic methylotrophy in various microbial hosts.
