Immobilized cell reactor-separator with simultaneous product separation and methods for design and use thereof

Claim 1

A method of preparing a volatile fermentation product from a non-volatile fermentable substrate, comprising: A. immobilizing cells on a gas porous, absorbent, inert solid matrix supported in a reactor-separator comprising a first fermenter enriching section and a second fermenter stripping section; B. continuously introducing a feed solution comprising liquid fermentable substrate and a first stripping gas into the first fermenter section wherein said fermentable substrate and said first stripping gas flow co-currently; C. contacting said immobilized cells in the first fermenter section with fermentable substrate wherein at least a part of said fermentable substrate is converted to volatile product and at least a part of said volatile product is stripped by the first stripping gas; D. introducing liquid effluent broth comprising fermentable substrate and volatile product from the first fermenter section into the second fermenter section wherein the broth moves countercurrent to a second stripping gas introduced into the second fermenter in a gas continuous environment; E. contacting immobilized cells in the second fermenter section with the liquid effluent broth comprising fermentable substrate and volatile product wherein said fermentable substrate is converted into volatile product, and wherein said volatile product enters the gas phase; F. recovering volatile fermentation product from gases exiting said first and second fermenter sections, wherein the concentration of volatile product and fermentable substrate each comprises less than 20 grams/liter of liquid effluent broth from the second fermenter section; wherein the combined residence time in both the first fermenter enriching section and second fermenter stripping section is between from 0.4 to 2.6 hours.

Claim 2

A method of preparing a volatile fermentation product from a non-volatile fermentable substrate, comprising: A. immobilizing cells on a gas porous, absorbent, inert solid matrix supported in a reactor-separator comprising a first fermenter enriching section and a second fermenter stripping section; B. continuously introducing a feed solution comprising liquid fermentable substrate and a first stripping gas into the first fermenter section wherein said fermentable substrate and said first stripping gas flow co-currently; C. contacting said immobilized cells in the first fermenter section with fermentable substrate wherein at least a part of said fermentable substrate is converted to volatile product and at least a part of said volatile product is stripped by the first stripping gas; D. introducing liquid effluent broth comprising fermentable substrate and volatile product from the first fermenter section into the second fermenter section wherein the broth moves countercurrent to a second stripping gas introduced into the second fermenter in a gas continuous environment; E. contacting immobilized cells in the second fermenter section with the liquid effluent broth comprising fermentable substrate and volatile product wherein said fermentable substrate is converted into volatile product, and wherein said volatile product enters the gas phase; F. recovering volatile fermentation product from gases exiting said first and second fermenter sections, wherein the concentration of volatile product and fermentable substrate each comprises less than 20 grams/liter of liquid effluent broth from the second fermenter section; wherein the combined residence time in both the first fermenter enriching section and second fermenter stripping section is between from 0.4 to 2.6 hours.