Enhancement of solvents production by clostridium acetobutylicum cultivated on a reducing compounds depletive medium

Abstract

The formation of acetone and n-butanol by Clostridium acetobutylicum strain ATCC 824 was monitored in batch culture grown on a chemically defined medium. Different techniques were used to exhaust the reducing compounds of the medium in order to increase acetone production. Fermentation under vacuum enhanced acetone production by a factor of two; if gases were eliminated by bubbling with nitrogen this factor became 1·7. The use of methylene blue resulted in an increase in acetone production of 88% and in butanol production of 43%. Pyruvic acid not only affected acetone production but also repressed glucose consumption. The fact that acetone production was not increased by addition of aminoacetonitrile indicated that the formation of acetone from acetoacetic acid is not a limiting reaction.