Direct in situ butanol recovery inside the packed bed during continuous acetone-butanol-ethanol (ABE) fermentation

In this study, the integrated in situ extraction-gas stripping process was coupled with continuous ABE fermentation using immobilized Clostridium acetobutylicum. At the same time, oleyl alcohol was cocurrently flowed into the packed bed reactor with the fresh medium and then recycled back to the packed bed reactor after removing butanol in the stripper. A high glucose consumption of 52 g/L and a high butanol productivity of 11 g/L/h were achieved, resulting in a high butanol yield of 0.21 g-butanol/g-glucose. This can be attributed to both the high bacterial activity for solvent production as well as a threefold increase in the bacterial density inside the packed bed reactor. Also reported is that 64 % of the butanol produced can be recovered by the integrated in situ extraction-gas stripping process. A high butanol productivity and a high glucose consumption were simultaneously achieved.