A Pseudomonas putida efflux pump acts on short-chain alcohols

Georg Basler*, Mitchell Thompson, Danielle Tullman-Ercek, Jay Keasling

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


Background: The microbial production of biofuels is complicated by a tradeoff between yield and toxicity of many fuels. Efflux pumps enable bacteria to tolerate toxic substances by their removal from the cells while bypassing the periplasm. Their use for the microbial production of biofuels can help to improve cell survival, product recovery, and productivity. However, no native efflux pump is known to act on the class of short-chain alcohols, important next-generation biofuels, and it was considered unlikely that such an efflux pump exists. Results: We report that controlled expression of the RND-type efflux pump TtgABC from Pseudomonas putida DOT-T1E strongly improved cell survival in highly toxic levels of the next-generation biofuels n-butanol, isobutanol, isoprenol, and isopentanol. GC-FID measurements indicated active efflux of n-butanol when the pump is expressed. Conversely, pump expression did not lead to faster growth in media supplemented with low concentrations of n-butanol and isopentanol. Conclusions: TtgABC is the first native efflux pump shown to act on multiple short-chain alcohols. Its controlled expression can be used to improve cell survival and increase production of biofuels as an orthogonal approach to metabolic engineering. Together with the increased interest in P. putida for metabolic engineering due to its flexible metabolism, high native tolerance to toxic substances, and various applications of engineering its metabolism, our findings endorse the strain as an excellent biocatalyst for the high-yield production of next-generation biofuels.

Original languageEnglish (US)
Article number136
JournalBiotechnology for Biofuels
Issue number1
StatePublished - May 11 2018


  • Efflux pumps
  • Higher alcohols
  • Next-generation biofuels
  • Pseudomonas putida
  • Short-chain alcohols
  • Tolerance
  • Toxicity
  • TtgABC

ASJC Scopus subject areas

  • Biotechnology
  • Applied Microbiology and Biotechnology
  • Renewable Energy, Sustainability and the Environment
  • Energy(all)
  • Management, Monitoring, Policy and Law


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