Extraction solvents derived from oil for alcohol removal in extractive fermentation
View Patent ↗In an alcohol fermentation process, oil derived from biomass is hydrolyzed into an extractant available for in situ removal of a product alcohol such as butanol from a fermentation broth. The glycerides in the oil can be catalytically (e.g., enzymatically) hydrolyzed into free fatty acids, which form a fermentation product extractant having a partition coefficient for a product alcohol greater than a partition coefficient of the oil of the biomass for the product alcohol. Oil derived from a feedstock of an alcohol fermentation process can be hydrolyzed by contacting the feedstock including the oil with one or more enzymes whereby at least a portion of the oil is hydrolyzed into free fatty acids forming a fermentation product extractant, or the oil can be separated from the feedstock prior to the feedstock being fed to a fermentation vessel, and the separated oil can be contacted with the enzymes to form the fermentation product extractant. The fermentation product extractant can be contacted with a fermentation broth for in situ removal of a product alcohol.
1. A method for producing a product alcohol comprising
(a) providing biomass comprising fermentable sugars, oil, and undissolved solids;
(b) liquefying the biomass to produce a feedstock slurry;
(c) separating an amount of oil from the feedstock slurry;
(d) hydrolyzing a portion of the remaining oil in the feedstock slurry of step (c) whereby the hydrolyzed oil forms an extractant;
(e) combining the feedstock slurry and extractant of step (d) with a fermentation broth; and
(f) fermenting the carbon source of the feedstock slurry to produce a product alcohol whereby the product alcohol is removed from the fermentation broth by partitioning into the extractant;
wherein the partition coefficient of the extractant for the product alcohol is greater than the partition coefficient of the oil for the product alcohol.
2. The method of claim 1 , wherein the portion of the remaining oil is hydrolyzed by one or more enzymes.
3. The method of claim 2 , wherein the one or more enzymes is selected from esterases, lipases, phospholipases, and lysophospholipases.
4. The method of claim 2 , further comprising:
inactivating the one or more catalysts after at least a portion of the oil is hydrolyzed to form the extractant.
5. The method of claim 1 , wherein the oil is separated by centrifugation, decantation, aspiration, siphoning, gravity settler, membrane-assisted phase splitting, or a combination thereof.
6. The method of claim 1 , further comprising separating the undissolved solids from the feedstock slurry.
7. The method of claim 1 , further comprising contacting the fermentation broth with a second extractant.
8. The method of claim 1 , wherein the extractant is recycled.
9. The method of claim 1 , wherein the product alcohol is selected from ethanol and butanol.
10. The method of claim 1 , wherein the product alcohol is selected from 1-butanol, 2-butanol, and isobutanol.
11. The method of claim 1 , wherein a portion of the separated oil in step (c) is hydrolyzed to form an extractant and is combined with the fermentation broth in step (e).
12. The method of claim 11 , wherein a portion of the separated oil is hydrolyzed by one or more enzymes.
13. The method of claim 12 , wherein the one or more enzymes is selected from esterases, lipases, phospholipases, and lysophospholipases.