The ethanol production from whey in a bioreactor integrated with direct contact membrane distillation (MDBR) was investigated. Fermentation was studied using concentrated whey and deproteinized whey enriched with lactose or sucrose. Whey lactose was prehydrolyzed in an enzymatic process using beta-galactosidase into a mixture of glucose and galactose. The fermentation process was performed using Saccharomyces cerevisiae yeasts species. It was found that MDBR can be successfully applied for ethanol production from whey. A continuous removal of produced ethanol and other volatile compounds from a fermenting broth by membrane distillation resulted in a high efficiency of sugar conversion into ethanol. The efficiency of ethanol production in MDBR in the fermentation of deproteinized whey enriched with sucrose was close to the theoretical value and 1.9x higher than that in the process carried out in a bioreactor without MD. It was found that salt present in the concentrated whey decreased the process efficiency. (C) 2016 Elsevier B.V. All rights reserved.