This invention is directed to methods for recovery of C3-C6 alcohols from
dilute aqueous solutions, such as fermentation broths. Such methods
provide improved volumetric productivity for the fermentation and allows
recovery of the alcohol. Such methods also allow for reduced energy use
in the production and drying of spent fermentation broth due to increased
effective concentration of the alcohol product by the simultaneous
fermentation and recovery process which increases the quantity of alcohol
produced and recovered per quantity of fermentation broth dried. Thus,
the invention allows for production and recovery of C3-C6 alcohols at low
capital and reduced operating costs.