Biological production of ethanol and butanol from syngas using Clostridium

Syngas can be generated from a number of sources such as biomass, municipal waste, steam reforming of natural gas and coal gasification.  Coskata is developing technologies to produce the commodity chemicals ethanol and n-butanol using syngas as an inexpensive feedstock, a situation brought about by the availability of cheap and abundant natural gas.  The process involves incubating modified species of Clostridium under anaerobic conditions in a bubble column reactor fed with syngas.  The carbon monoxide, carbon dioxide and hydrogen in the gaseous phase equilibrate with the liquid phase during vertical transit of the pressurized gas through the reactor, and in turn the dissolved gases enter the bacterial cytoplasm.  Several species of Clostridium encode enzymes of the Wood-Ljundahl pathway, which is the essential component for converting these carbon oxides into ethanol and n-butanol via acetyl-CoA, either in a specific monoculture or in cultures containing more than one species of bacteria.  Genetic modifications have enabled improvements to strains so that the production of alcohols has become more efficient over time.  This presentation will describe the fermentation process developed at Coskata to enable commercial scale production of n-butanol and fuel ethanol.