An integrated in situ extraction-gas stripping process for Acetone–Butanol–Ethanol (ABE) fermentation

A novel integrated in situ extraction-gas stripping process (Process 3 in this study) is proposed for running batch Acetone–Butanol–Ethanol (ABE) fermentation. The process involves two butanol separation processes in which butanol is first extracted by oleyl alcohol during ABE fermentation and gas stripping is carried out on butanol in the oleyl alcohol phase at the same time. The butanol productivity and yield of Process 3 is 0.28 ± 0.01 g/L/h and 0.226 ± 0.001 g-butanol/g-glucose. The ABE productivity and yield are 0.46 ± 0.01 g/L/h and 0.374 ± 0.002 g-ABE/g-glucose. Glucose utilization was 97% and initial glucose consumption was 121 ± 2 g/L. Butanol and ABE concentrations of 93–113 and 166–204 g/L in the condensate can be achieved. This study demonstrates that Process 3 as described here enhances ABE fermentation and also results in the production of high purity solvents.