Electron receptor addition enhances butanol synthesis in ABE fermentation by Clostridium acetobutylicum

Abstract

The techniques for enhancing butanol production in ABE fermentation by Clostridium acetobutylicum generally focus on adding electron carrier to strengthen NADH synthesis, repressing hydrogenase by aerating CO, supplementing butyrate, etc. However, those methods suffer from the problems of total solvent decrease, high purification cost, using expensive supplemental substances, etc. In this study, we added small amount of electron receptors (Na₂SO₄/CaSO₄, 2g/L) into ABE fermentation broth: to alter electron/proton distributions in the intracellular electron transport shuttle system, directing more electron/proton pairs into NADH synthesis route; to stimulate intracellular accumulation of those amino acids favorable for cells survival/butanol synthesis. In ABE fermentation in a 7L fermentor, adding 2g/L Na₂SO₄ could raise butanol concentration to a higher level of 12.96g/L, which was 34.8% higher than that of the control. Addition of tiny amount cheap electron receptor would provide a new way to enhance bio-butanol production.

Keywords: ABE fermentation; Butanol; Clostridium acetobutylicum; Electron receptor; Electron/proton transition.