A coupled fermentation/pervaporation process for reliable production of concentrated ethanol was studied using ethanol permselective silicalite membranes coated with two types of silicone rubber, KE-45 and KE-108, as a hydrophobic material. Ethanol recovery was greatly improved by using a membrane coated with KE-45 silicone rubber. The recovered ethanol concentration in the permeate was 67% (w/w), and the amount of recovered ethanol from the broth was more than 10 times higher than that using a non-coated membrane. Succinic acid and glycerol, by-products created during fermentation, interfered with the pervaporation performance of the coated membrane when used to separate an ethanol/water solution. (C) 2003 Society of Chemical Industry.
