Engineering butanol-tolerance in escherichia coli with artificial transcription factor libraries.

Escherichia coli has been explored as a host for butanol production because of its many advantages such as a fast growth and easy genetic manipulation. Butanol toxicity, however, is a major concern in the biobutanol production with E. coli. In particular, E. coli growth is severely inhibited by butanol, being almost completely stopped by 1% (vol/vol) butanol. Here we developed a new method to increase the butanol-tolerance of E. coli with artificial transcription factor (ATF) libraries which consist of zinc finger (ZF) DNA-binding proteins and an E. coli cyclic AMP receptor protein (CRP). Using these ATFs, we selected a butanol-tolerant E. coli which can tolerate up to 1.5% (vol/vol) butanol, with a concomitant increase in heat resistance. We also identified genes of E. coli that are associated with the butanol-tolerance. These results show that E. coli can be engineered as a promising host for high-yield butanol production.