CaCO supplementation alleviates the inhibition of formic acid on acetone/butanol/ethanol fermentation by Clostridium acetobutylicum.

Qi, Gaoxiang; Xiong, Lian; Lin, Xiaoqing; Huang, Chao; Li, Hailong; Chen, Xuefang; Chen, Xinde

Objective: To investigate the inhibiting effect of formic acid on acetone/butanol/ethanol (ABE) fermentation and explain the mechanism of the alleviation in the inhibiting effect under CaCO supplementation condition. Results: From the medium containing 50 g sugars l and 0.5 g formic acid l, only 0.75 g ABE l was produced when pH was adjusted by KOH and fermentation ended prematurely before the transformation from acidogenesis to solventogenesis. In contrast, 11.4 g ABE l was produced when pH was adjusted by 4 g CaCO l. The beneficial effect can be ascribed to the buffering capacity of CaCO. Comparative analysis results showed that the undissociated formic acid concentration and acid production coupled with ATP and NADH was affected by the pH buffering capacity of CaCO. Four millimole undissociated formic acid was the threshold at which the transformation to solventogenesis occurred. Conclusion: The inhibiting effect of formic acid on ABE fermentation can be alleviated by CaCO supplementation due to its buffering capacity.

CALCIUM carbonate; DIETARY supplements; FORMIC acid; INHIBITION (Chemistry); FERMENTATION; CLOSTRIDIUM acetobutylicum

Biotechnology Letters, 2017, Vol 39, Issue 1, p97

0141-5492

Academic Journal

10.1007/s10529-016-2231-z