Efficient production of acetone–butanol–ethanol (ABE) from cassava by a fermentation–pervaporation coupled process

• Continuous ABE production from cassava was studied by a fermentation–PV coupled process.
• The coupled process offered higher solvent yield and productivity.
• A concentrated permeate containing 201.8 g/L ABE with 122.4 g/L butanol was obtained.
• The membrane performance was stable during continuous ABE production from cassava.

Production of acetone–butanol–ethanol (ABE) from cassava was investigated with a fermentation–pervaporation (PV) coupled process. ABE products were in situ removed from fermentation broth to alleviate the toxicity of solvent to the Clostridium acetobutylicum DP217. Compared to the batch fermentation without PV, glucose consumption rate and solvent productivity increased by 15% and 21%, respectively, in batch fermentation–PV coupled process, while in continuous fermentation–PV coupled process running for 304 h, the substrate consumption rate, solvent productivity and yield increased by 58%, 81% and 15%, reaching 2.02 g/L h, 0.76 g/L h and 0.38 g/g, respectively. Silicalite-1 filled polydimethylsiloxane (PDMS)/polyacrylonitrile (PAN) membrane modules ensured media recycle without significant fouling, steadily generating a highly concentrated ABE solution containing 201.8 g/L ABE with 122.4 g/L butanol. After phase separation, a final product containing 574.3 g/L ABE with 501.1 g/L butanol was obtained. Therefore, the fermentation–PV coupled process has the potential to decrease the cost in ABE production.