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Optimized expression of Hfq protein increases Escherichia coli growth by enhancing acid resistance
  • Phuong Vo,
  • Dokyun Na
Phuong Vo
Chung-Ang University
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Abstract

Escherichia coli is a widely used platform for metabolic engineering, for fast growth and well-established engineering techniques. However, there has been a demand for faster growing E. coli for higher production of desired substances. Here, we optimized Hfq protein expression, which plays an essential role in stress response, to increase stress tolerance by designing the ribosome binding site of the hfq gene thereby increasing cell growth. As a result, Hfq expression correlated with growth rate, and its optimal expression increased the maximal optical density in the stationary phase by 30.9% relative to that in the wild-type E. coli. RNA-seq and network analyses revealed the upregulation of stress response genes specifically that of the gadE gene, a transcription factor involved in acid resistance. The optimized gadE expression also increased the optical density of E. coli by 22.8%, while co-expression of hfq and gadE genes increased growth by up to 29.7%. In conclusion, our optimized Hfq increased E. coli optical density by improving cellular stress response, specifically acid tolerance. The fast-growing E. coli constructed in this study would be a useful metabolic engineering platform for the production of proteins and other desired substances