The batch fermentation combined with the removal of ethanol from the broth by means of membrane distillation process (MD) has been investigated. The porous capillary polypropylene membranes were used for the separation of volatile compounds from the feed (broth), formed as a result of fermentation. The elimination of these compounds allows increase in the productivity and the rate of conversion of sugar to ethanol, since they act as inhibitors. In the case of fermentation combined with the MD, the efficiency of 0.4-0.51 (g EtOH)/(g of sugar) and the production rate of 2.5-4 (g EtOH)/dm(3) h was achieved in relation to 0.35-0.45 (g EtOH)/(g of sugar) and 0.8-2 (g EtOH)/dm(3) h obtained in:the classical batch fermentation. The ethanol Aux obtained in membrane distillation varied in the range of 1-4 (kg EtOH)/m(2) per day and was dependent on the temperature and the feed composition. (C) 2000 Elsevier Science B.V. All rights reserved.