Application of Clostridial Species for the Production of Alcohols and Carboxylic Acids

Abstract

The genus Clostridium is the second largest one in prokaryotes and consists of Gram-positive, strictly anaerobic, endospore forming bacteria. In addition to their pathological importance, they had been widely exploited for large-scale production of acetone and butanol in the early 20th century. Even though such biochemical processes are no longer economically feasible today, these bacteria still have been attracting great attention of researchers since these bacteria exhibitdiverse metabolic features including anaerobic amino acid catabolism (Stickland reaction), carbon fixation via the Wood-Ljungdahl pathway, etc., as well as 1-butanol production. In the first part of this lecture, we will introduce previousresults while studying on metabolic engineering and physiology of heterotrophic clostridia. The second part consists of the recent progress with Clostridium sp. AWRP, an acetogenic strain producing acetate, ethanol, and 2,3-butanediol. Based on our bioreactor experiments and in silico stoichiometric analyses, we will discuss the metabolism of acetogenic clostridia and hurdles to overcome for strain improvement. [This work was supported by the KIOST in-house program (PE99722)and C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (2015M3D3A1A01064884).]