We address two major challenges facing commercialization of acetone-butanol-ethanol (ABE) fermentation: product inhibition and low productivity. We studied a polystyrene-b-polydimethylsiloxane-bpolystyrene (SDS) triblock copolymer membrane for selective removal of butanol from aqueous solutions by pervaporation. The SDS membrane exhibited higher permeabilities than a commercially available cross linked polydimethylsiloxane (PDMS) membrane. Both types of pervaporation membrane were also used for in situ product removal of ABE biofuels in Clostridium acetobutylicion fermentations operated in a semi-conlinuous mode. Membrane performance and iLs erred on the fermenLaLion process were assessed by measuring flux, OD600 and conceraraLions of different componeras in LAte fermenLer as a funcrion of lime. VolumeLric ABE producliviLy increased from 045 g/(L h) in simple baLch fermenLalion Lo 0.66 g/(L h) in the case of pervaporaLive-fermenLaLion with the PDMS membrane. A further increase in producliviry Lo 0.94 g/(L h) was obtained in Lhe case of pervaporaLive-fermenrarion with Lhe SDS membrane. Overall, LoLal ABE producLion improved by a facLor of three, viable fermenLalion Lime increased by a facror of two, and cell densiLy increased by a facLor of 2.5 upon applying SDS membrane pervaporation, relative to the batch process. Published by Elsevier B.V.