NOVELTY - Producing a renewable hydrocarbon composition, involves: (a) providing a biomass feedstock; (b) processing the biomass feedstock to produce a processed feedstock slurry; (c) adding the processed feedstock slurry to a fermentation medium; (d) contacting the fermentation medium comprising processed feedstock slurry with a recombinant yeast host cell modified to produce a fermentation composition comprising isobutanol from carbohydrate and from protein hydrolyzate; and (e) recovering a renewable hydrocarbon composition from the fermentation composition by distillation.    USE - The method is useful for producing a butanol and fusel oil mixture from a biomass feedstock (claimed), where the butanol is useful as a fuel, fuel component and fuel additive, as a chemical solvent, feedstock in various chemical markets, such as the plastics industry, and as a food grade extractant in the food and flavor industry.    ADVANTAGE - The method increases the yield of butanol and fusel oil in the butanol and fusel oil mixture. The biosynthesis of butanol directly from plant-derived raw materials improves economic viability.    DETAILED DESCRIPTION - Producing a renewable hydrocarbon composition comprising isobutanol, involves: (a) providing a biomass feedstock; (b) processing the biomass feedstock to produce a processed feedstock slurry comprising protein hydrolyzates and fermentable carbohydrate; (c) adding the processed feedstock slurry to a fermentation medium; (d) contacting the fermentation medium comprising processed feedstock slurry with a recombinant yeast host cell modified to produce a fermentation composition comprising isobutanol from carbohydrate and from protein hydrolyzate; and (e) recovering a renewable hydrocarbon composition from the fermentation composition by distillation, where the renewable hydrocarbon composition comprising isobutanol is produced. An INDEPENDENT CLAIM is included for producing a butanol and fusel oil mixture from a biomass feedstock comprising (a1) providing a biomass feedstock, (b1) processing the biomass feedstock to produce a processed feedstock slurry comprising protein hydrolyzates and oligosaccharides, (c1) saccharifying the oligosaccharides of the processed feedstock slurry to produce a fermentation composition comprising fermentable sugars and protein hydrolyzates, (d1) fermenting a recombinant yeast in the presence of the fermentation composition, where the recombinant yeast comprising (i) a heterologous butanol biosynthetic pathway for production of butanol, and (ii) at least one upregulated Ehrlich pathway gene for production of fusel oil, and a butanol and fusel oil mixture is produced, and (e1) recovering the butanol and fusel oil mixture, where the yield of the butanol and fusel oil mixture per kilogram of biomass feedstock is increased as compared to that produced by a recombinant yeast which does not comprise at least one upregulated Ehrlich pathway gene and recovered.