PROCESS FOR THE PRODUCTION OF ETHANOL AND BUTANOL
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Abstract
The present invention relates to a process for the production of ethanol and butanol from biomass, and in particular to a process for the production of ethanol and butanol using two separate fermentation step subjecting the biomass feedstock to anaerobic fermentation at a pH below 6.0 and at a temperature in the range 20 to 700° C. and so as to convert the biomass to a product predominantly comprising acetic acid and butyric acid with at least a 2:1 ratio by weight of acetic acid to butyric acid, c) treating the product of stream of step (b) to separate a solution comprising the acetic acid and butyric acid by: (i) separating a solution comprising the acetic acid and butyric acid from any residual solids and (ii) separating bacteria and/or pasteurizing or sterilizing the solution from the first fermentation step, and d) in a second fermentation step fermenting the solution comprising the acetic acid and butyric acid from the step (c) to form ethanol and butanol.
7 Citations
22 Claims
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1-21. -21. (canceled)
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22. A process for the production of ethanol and butanol using two separate fermentation steps—
- comprising;
a) first fermentation step comprising fermenting;
wherein subjecting said feedstock to anaerobic fermentation in the presence of acetogenic bacteria, further comprising a mixture of bacterial strains, at a pH below 6.0, at a temperature in the range 20 to 70 degree C., converting said feedstock to a product predominantly comprising acetic acid and butyric acid;
wherein ratio of acetic acid to butyric acid is at least 2;
1;b) treating said product predominantly comprising acetic acid and butyric acid of step a) to separate a solution comprising the acetic acid and butyric acid by; (i) separating residual solids; and (ii) separating bacteria;
optionally pasteurizing;
optionally sterilizing said solution comprising the acetic acid and butyric acid;c) second fermentation step comprising fermenting in the presence of solventogenic bacteria said solution comprising the acetic acid and butyric acid from step b) to form ethanol and butanol; d) third fermentation step comprising a portion of said feedstock to said first fermentation step is anaerobically digested by a methanogenic bacteria to produce methane;
optionally a portion of said solution comprising the acetic acid and butyric acid of step b) is anaerobically digested by a methanogenic bacteria in said third fermentation step to produce methane.
- comprising;
Specification