Method to enhance yeast growth for fermentative bioproduct production, and nutrient composition for same

A method for fermentative bioproduct production, comprising:

• culturing at least one yeast in a growth medium containing a nutrient composition to obtain a propagated yeast culture, wherein the nutrient composition comprises corn steep liquor and at least one of (a) at least one antifoaming agent wherein the at least one organic antifoaming agent is a polyglycol, a blend of polyglycol and silicone, a fatty acid ethoxylate, an ethoxylated fatty amine, or any combination thereof, or (b) at least one surfactant wherein the at least one surfactant is a nonionic surfactant that is an ethoxylated sorbitan ester, a glyceride ethoxylate, an ethoxylated castor oil, an alcohol ethoxylate, an alkylphenol ethoxylate, a phenol ethoxylate, an amide ethoxylate, a fatty acid ethoxylate, a fatty amine ethoxylate, a fatty amide ethoxylate, a fatty mono or di-ethanolamide, an alkyl glycoside, a polyethylene glycol (PEG), an acetylenic glycol, a polypropylene glycol (PPG), a poloxamer, an alkali metal arylsulfonate, an ethoxylated fatty amide, or any combination thereof,
• wherein said at least one yeast comprises Saccharomyces cerevisiae, Saccharomyces pastorianus (carlsbergiensis), Kluyveromyces lactis, Kluyveromyces fragilis, Fusarium oxysporum, or any combinations thereof;
• inoculating a fermentation substrate with the propagated yeast culture to produce a fermentable biomass;
• fermenting the fermentable biomass to produce a fermented biomass comprising at least one bioproduct and non-fermented solids content;
• and
• separating at least a portion of the at least one bioproduct from the solids content,
• wherein a) addition of the nutrient composition results in an increased yeast concentration in the propagation and fermentation tanks of at least 3 million cells per gram as compared to a yeast concentration in the propagation and fermentation tanks wherein the culturing is done with addition of only the same amount of said corn steep liquor and without the at least one antifoaming agent, or
• wherein b) addition of the nutrient composition results in an increased ethanol concentration in the fermented biomass of at least 1% w/v as compared to an ethanol concentration in the propagation and fermentation tanks wherein the culturing is done with addition of only the same amount of corn steep liquor and without the at least one antifoaming agent and at least one surfactant, or both.