Patent ID: 8535413

Claim:
A fermentation process to recover ethanol which comprises: a. providing a fermentor capable of being charged with water, a fermentation enhancer and a source for the creation of the ethanol of the fermentation reaction; b. operating the fermentor at a temperature where the vapor pressure of the water-ethanol vapor phase mixture is sufficient to permit a membrane separator to concentrate the ethanol; c. flowing a gas into the fermentor to enhance the ethanol separation in the water-ethanol vapor phase; d. passing the water-ethanol vapor phase mixture through a compressor into a membrane separation unit; e. recovering ethanol from the membrane separation unit as the permeate; f. passing the stream reduced in ethanol back into the fermentor; g. and passing a water CO 2 stream through a membrane to separate CO 2 for recycle into the fermentor and a concentrated H2O stream for discharge or recycle into the fermentor.