The fermentation of lactose to ethanol can be performed using yeast species Saccharomyces cerevisiae. The strategy involved the fermentation of prehydrolyzed lactose solutions in an enzymatic process using beta-galactosidase. The yeast consumes the resulting mixtures of glucose and galactose producing ethanol. Ethanol from lactose solutions in a BIOTRON bioreactor integrated with a direct contact membrane distillation system (DCMD) was produced. During MD, the transport of volatile products of fermentation proceeded across the polypropylene, porous membrane submerged in the bioreactor. It was found that the bioreactor integrated with DCMD can be successfully applied for ethanol production from lactose. A continuous removal of ethanol and other volatile products of fermentation from the broth, through the porous, hydrophobic membrane, resulted in an increase of ethanol productivity from lactose in comparison with the results obtained in a process performed in a classical reactor. (C) 2013 Elsevier B.V. All rights reserved.