(722d) Development and Application of Genetic Tools for an Industrial Strain of Solventogenic Clostridium

The production of ABE (acetone, butanol, ethanol) by the anaerobic bacteria Clostridium is a bioprocess capable of converting various renewable substrates into high value solvents and fuels. While ABE fermentation by Clostridium has been performed on an industrial scale since the early 1900s, several significant technical challenges have prevented this process from being economically competitive with the conventional production of solvents and fuels from petroleum. Among these challenges is the lack of genetic tools available for manipulating the powerful metabolism of many of these organisms. While progress has been made in developing genetics for a handful of strains over the last 25 years, a vast majority of known solventogenic Clostridium strains remain genetically intractable. Here, we discuss our development of a genetic transformation method for the industrial butanol hyperproducer Clostridium saccharoperbutylacetonicum strain N1-4. While the wild type strain has been used on the industrial scale in Japan since the 1940s, we have demonstrated, for the first time, the use of rational metabolic engineering to expand the range of high value solvents produced in this strain. While the final applications of these genetic tools are important, we believe that discussing the successes and failures encountered while developing this genetic transformation method will help others in approaching genetics in other intractable species of Clostridium.