Enhancement of butanol production and reducing power using a two-stage controlled-pH strategy in batch culture of Clostridium acetobutylicum XY16

The effects of pH control on the process of acetone/butanol/ethanol (ABE) production in batch cultures of Clostridium acetobutylicum XY16 have been investigated. Based on the specific acid- and solvent-forming rates in batch fermentation at different pH values (from 4. 3 to 6. 0), a two-stage controlled-pH strategy was developed in which the pH was shifted from 5. 5 to 4. 9 after a dry cell weight of 0. 5 g L^-1 was achieved. By applying this strategy, the maximum ABE concentration and productivity reached 20. 3 g L^-1 and 0. 63 g L^-1 h ^-1, and were significantly improved by 12. 2 and 40. 1 %, respectively, compared with the process with no pH control. In addition, reducing power capability was significantly enhanced by this strategy. The two-stage controlled-pH strategy was a convenient and rapid method for high intensity ABE production.