Patent ID: 7309602

Claim:
A method of fermentation using carbon-containing material, comprising (a) mixing a carbon-containing material with a culture comprising genetically modified yeast cells that, in a fermentation reaction, produce an alcohol and a fermentation residual comprising a nutrient selected from the group consisting of an amino acid, a cofactor, a hormone, a protein, a vitamin and a lipid, wherein the yeast cells comprise a recombinant expression vector comprising an exogenous nucleotide sequence encoding a polypeptide and a regulatory sequence that controls the expression of the polypeptide, wherein the expression of said exogenous nucleotide sequence results in increased production of said polypeptide and said nutrient and enhanced concentration of the nutrient _ in the fermentation residual compared with the concentration of the nutrient in a fermentation residual produced by an unmodified corresponding yeast cell when used in the fermentation reaction; (b) fermenting the culture under conditions suitable for production of the alcohol and under conditions suitable for production the polypeptide and the nutrient; (c) separating the alcohol from the culture; and (d) producing the fermentation residual comprising the nutrient.