METHODS FOR THE ECONOMICAL PRODUCTION OF BIOFUEL PRECURSOR THAT IS ALSO A BIOFUEL FROM BIOMASS
Methods for producing a biofuel precursor are provided. Also provided are biocatalysts that convert a feedstock to a biofuel precursor.
1 . An animal feed product comprised of distillers dried grains derived from a fermentation process for the production of isobutanol, wherein said distillers dried grains comprise a spent yeast biocatalyst, said spent yeast biocatalyst engineered to express an isobutanol producing metabolic pathway comprising at least one exogenous gene.
2 . The animal feed product of claim 1 , wherein said yeast biocatalyst does not contain DNA markers.
3 . The animal feed product of claim 1 , wherein said yeast biocatalyst includes DNA consisting of natural DNA.
4 . The animal feed product of claim 1 , wherein said isobutanol producing metabolic pathway comprises the following substrate to product conversions:
(a) pyruvate to acetolactate;
(b) acetolactate to 2,3-dihydroxyisovalerate;
(c) 2,3-dihydroxyisovalerate to α-ketoisovalerate;
(d) α-ketoisovalerate to isobutyraldehyde; and
(e) isobutyraldehyde to isobutanol.
5 . The animal feed product of claim 1 , wherein said yeast biocatalyst expresses an exogenously encoded acetolactate synthase.
6 . The animal feed product of claim 1 , wherein said yeast biocatalyst expresses an exogenously encoded ketol-acid reductoisomerase.
7 . The animal feed product of claim 1 , wherein said yeast biocatalyst expresses an exogenously encoded dihydroxy acid dehydratase.
8 . The animal feed product of claim 1 , wherein said yeast biocatalyst expresses an exogenously encoded keto-isovalerate decarboxylase.
9 . The animal feed product of claim 1 , wherein said yeast biocatalyst expresses an exogenously encoded isobutyraldehyde dehydrogenase.
10 . The animal feed product of claim 1 , wherein said yeast biocatalyst is derived from Saccharomyces cerevisiae.
11 . The animal feed product of claim 1 , wherein said distillers dried grains comprise at least one additional product selected from the group consisting of unconsumed feedstock solids, nutrients, proteins, fibers, and oils.
12 . A method for producing distillers dried grains derived from a fermentation process for the production of isobutanol, said method comprising:
(a) cultivating a yeast biocatalyst in a fermentation medium comprising at least one carbon source, wherein said yeast biocatalyst is engineered to express an isobutanol producing metabolic pathway comprising at least one exogenous gene;
(b) harvesting insoluble material derived from the fermentation process, said insoluble material comprising said yeast biocatalyst; and
(c) drying said insoluble material comprising said yeast biocatalyst to produce the distillers dried grains.
13 . The method of claim 12 , wherein said yeast biocatalyst does not contain DNA markers.
14 . The method of claim 12 , wherein said yeast biocatalyst includes DNA consisting of natural DNA.
15 . The method of claim 12 , wherein said method further comprises step (d) of adding soluble residual material from the fermentation process to said distillers dried grains to produce distillers dried grains and solubles.
16 . The method of claim 12 , wherein said distillers dried grains comprise at least one additional product selected from the group consisting of unconsumed feedstock solids, nutrients, proteins, fibers, and oils.
17 . The method of claim 12 , wherein said isobutanol producing metabolic pathway comprises the following substrate to product conversions:
(a) pyruvate to acetolactate;
(b) acetolactate to 2,3-dihydroxyisovalerate;
(c) 2,3-dihydroxyisovalerate to α-ketoisovalerate;
(d) α-ketoisovalerate to isobutyraldehyde; and
(e) isobutyraldehyde to isobutanol.
18 . The method of claim 12 , wherein said yeast biocatalyst is derived from Saccharomyces cerevisiae.