Microbial production of ethanol from carbon monoxide

Production of ethanol from fermentation of CO has received much attention in the last few years with several companies proposing to use CO fermentation in their ethanol production processes. The genomes of two CO fermenters, Clostridium ljungdahlii and Clostridium carboxidivorans, have recently been sequenced. The genetic information obtained from this sequencing is aiding molecular biologists who are enhancing ethanol and butanol production by genetic manipulation. Several studies have optimized media for CO fermentation, which has resulted in enhanced ethanol production. Also, new reactor designs involving the use of hollow fiber membranes have reduced mass transfer barriers that have hampered previous CO fermentation efforts.

► The sequences of the genomes for two CO fermenters, Clostridium ljungdahlii and Clostridium carboxidivorans, have been recently sequenced and published. ► Several studies have optimized media for CO fermentation in recent years. ► Hollow fiber membrane reactors have recently been adapted by Coskata, a company commercializing ethanol production from CO, to increase mass transfer of CO to fermenting bacteria.