Ethanol production in membrane distillation bioreactor

The batch fermentation combined with the removal of ethanol from the broth by means of membrane distillation process (MD) has been investigated. The p orous capillary polypropylene membranes were used for the separation of vol atile 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. I n 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 wa s 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 obt ained in membrane distillation varied in the range of 1-4 (kg EtOH)/m(2) pe r day and was dependent on the temperature and the feed composition. (C) 20 00 Elsevier Science B.V. All rights reserved.