Consolidated bioprocessing represents an attractive approach to converting cellulosic materials into bioethanol, yet is practically unavailable. We developed a ventilation-mediated, simultaneous ethanol fermentation and recovery system. Running the system under air-supplied conditions, apparently pure ethanol (28 g) was recovered from cellobiose (100 g) by growing recombinant Kluyveromyces marxianus expressing beta-glucosidase. (C) 2011, The Society for Biotechnology, Japan. All rights reserved.