The selective recovery of alcohols from fermentation broths by pervaporation

Pervaporation can be successfully utilized to recover various alcohols from fermentation broths and dilute process streams. Hydrophobic membranes, such as silicone-based polymers, have been employed in this application to produce an enriched product. Research in this field has increased dramatically in the past five years and a review of this work is warranted. Fermentations of n-butanol, ethanol, and isopropanol all yielded positive results. The direct integration of a membrane with a bioreactor makes the process more efficient and reduces the effects of product inhibition. A majority of researchers have investigated selective organic permeation from binary aqueous mixtures. These results provide an excellent data base on the permeabilities of alcohols through various membranes. This paper specifically addresses the application of pervaporation to the selective permeation of alcohols from dilute mixtures with particular reference to fermentation broths.