Triggering the stringent response enhances synthetic methanol utilization in Escherichia coli

Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methylotrophs have proved successful, autonomous methylotrophy, i.e. the abil...

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Bibliographic Details
Published in:Metabolic engineering 2020-04, Vol.61
Main Authors: Bennett, R. Kyle, Agee, Alec, Gerald Har, Jie Ren, von Hagel, Bryan, Siu, Ka-Hei, Antoniewicz, Maciek R., Papoutsakis, Eleftherios T.
Format: Article
Language:English
Subjects:
60 APPLIED LIFE SCIENCES
Escherichia coli
Methanol
ppGpp
Stringent response
Synthetic methylotrophy
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Summary:Synthetic methylotrophy aims to engineer methane and methanol utilization pathways in platform hosts like Escherichia coli for industrial bioprocessing of natural gas and biogas. While recent attempts to engineer synthetic methylotrophs have proved successful, autonomous methylotrophy, i.e. the ability to utilize methane or methanol as sole carbon and energy substrates, has not yet been realized. Here in this paper, we address an important limitation of autonomous methylotrophy in E. coli: the inability of the organism to synthesize several amino acids when grown on methanol. By activating the stringent/stress response via ppGpp overproduction, or DksA and RpoS overexpression, we demonstrate improved biosynthesis of proteinogenic amino acids via endogenous upregulation of amino acid synthesis pathway genes. Thus, we were able to achieve biosynthesis of several limiting amino acids from methanol-derived carbon, in contrast to the control methylotrophic E. coli strain. This study addresses a key limitation currently preventing autonomous methylotrophy in E. coli and possibly other synthetic methylotrophs and provides insight as to how this limitation can be alleviated via stringent/stress response activation.
ISSN:1096-7176
1096-7184