Antimicrobial method for fermentation processes
AssigneeDeLaval Holding AB
InventorsReed Semenza, Michael Welker
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Abstract
A system and method for controlling bacteria, especially lactic and acetic acid bacteria in the production of ethanol using an organic oxidizing compound in combination with an inorganic oxidizer is provided. Particularly, a mixture of one or more peroxy acids and one or more peroxide compounds is introduced into a fermentation mash so as to inhibit or reduce levels of bacteria that compete with yeast for the fermentation sugars. The peroxy acid and peroxide compounds largely are consumed during the fermentation process and are generally not present in the fermentation by-products, especially recovered distiller's grains.
Claims24
A method of controlling lactic acid levels within an ethanol fermentation system comprising:
- introducing peracetic acid and hydrogen peroxide into a fermentation mash located within said ethanol fermentation system, wherein said peracetic acid is introduced into said fermentation mash at a level of less than 50 ppm and said hydrogen peroxide is introduced into said fermentation mash at a level of less than 50 ppm, wherein said fermentation mash comprises an aqueous suspension of fiber, wherein a first portion of said hydrogen peroxide is added to said fermentation mash prior to the introduction of said peracetic acid into said fermentation mash, and wherein said peracetic acid is introduced into said fermentation mash as a mixture with a second portion of said hydrogen peroxide;
- and
- fermenting said fermentation mash with an ethanol-producing yeast, at least a portion of said peracetic acid and said hydrogen peroxide being present in said fermentation mash during said fermenting step at levels sufficient to prevent lactic acid levels within said system from exceeding 0.20% by weight of a liquid portion of said fermentation mash.
Dependencies are inferred from the claim text.