B-vitamin requirements of Clostridium autoethanogenum

Vitamins are micronutrients essential for life in an organism which must be obtained from diet or environment. Standard media often contains ten B-vitamins, which act as cofactors or precursors for co-enzymes. Clostridium autoethanogenum and Clostridium ljungdahlii are two obligately anaerobic acetogens which can utilize syngas (carbon dioxide, hydrogen and carbon monoxide) as a carbon source, generated from industrial waste gases or gasification of hydrocarbons. Clostridium autoethanogenum and Clostridium ljungdahlii use the Wood-Ljungdahl pathway to generate Acetyl-CoA from syngas. Acetyl-coA can be used by the bacterium for growth, production of energy and acetate, ethanol and 2,3-butanediol production. To increase the industrial attractiveness of producing chemicals via this route, the process must be as economical as possible and one way to increase the economic viability is to only add essential media components. This study attempted to define the exact B-Vitamin requirements of the two species, to show that the two species require only three “vitamins” – biotin, pantothenate and thiamine. Strains were created which have missing biotin and pantothenate pathway genes added in order to confer prototrophy for the vitamins and to determine the effects the addition of these genes had on viability, growth profile and product profile. A Continuous Stirred Tank reactor experiment was conducted in order to determine the effects of pantothenate, and therefore, Acetyl-CoA limitation on a continuously growing culture which mimicked an industrial reactor. Increased efficiency of the media could lead to a more economically attractive process for the sustainable production of the platform chemical than from fossil fuels leading us one step closer to decoupling our civilisation from oil