Use of erythromycin as a selective antimicrobial agent in the production of alcohols

Abstract

A process for the use of low concentration levels of Erythromycin to eliminate or control the growth of unwanted or undesirable bacteria (contaminating bacteria) in the fermentation production of alcohols without inhibition of the growth or replication of the yeast.

1 . A method for increasing the amount of alcohol produced during large scale alcohol production comprising:
 introducing an antibiotic as an active agent to a vessel used during alcohol production to render an ideal environment for a fermentation mixture when combined with the antibiotic for fermenting the fermentation mixture into the desired alcohol;   the active agent functions to substantially reduce any deleterious effects of at least one contaminating bacteria present in said fermentation mixture while not having any deleterious effects on the yeast; and   wherein the active agent is added to said vessel in an amount ranging from at least 0.5 ppm to about 6 ppm of the fermentation mixture and is selected from the group consisting of Erythromycin and derivatives or salts of Erythromycin.   
     
     
         2 . The method of  claim 1 , wherein the antibiotic is added in an amount ranging from 0.5 to 3 ppm per part of the fermentation mixture. 
     
     
         3 . The method of  claim 1 , wherein the alcohol produced is ethanol. 
     
     
         4 . The method of  claim 1 , wherein the vessel is a fermentation tank and the antibiotic is introduced therein. 
     
     
         5 . The method of  claim 1 , wherein the vessel is a yeast propagation tank and the antibiotic is introduced therein. 
     
     
         6 . The method of  claim 1 , wherein the fermentation mixture is derived from any feedstock selected from the group consisting of: corn, wheat, triticale, barley, cassava, rye, graded starch stream rendered from said feedstocks, sugar cane, sugar beet, molasses, rice straw, potato waste, wood waste, switch grass, pine and other wood derivatives, municipal waste, food waste, alcoholic and non-alcoholic beverage industry waste and mixtures thereof. 
     
     
         7 . The method of  claim 1 , wherein in addition to alcohol being produced co-products result and the antibiotic in these co-products is low or at a non-detectable level. 
     
     
         8 . The method of  claim 1 , wherein the antibiotic is present in a low or non-detectable level in the produced co-products. 
     
     
         9 . The method of  claim 1 , wherein the antibiotic functions to inhibit protein synthesis at a ribosomal level thus controlling or lysing the contaminating bacteria growth while being unable to penetrate the nucleus of the yeast cell thus rendering the antibiotic harmless to yeast during fermentation. 
     
     
         10 . A fermentation mixture used in the production of ethanol comprising yeast, carbohydrates and 0.5 ppm to about 6 ppm of Erythromycin, wherein the Erythromycin inhibits growth of microorganisms competing for the yeast thereby increasing the amount of alcohol produced from the fermentation mixture. 
     
     
         11 . A method for controlling the growth of lactic acid bacteria in a fermentation process for the production of alcohol comprising:
 adding a minimum inhibitory concentration of Erythromycin or derivatives or salts thereof to a vessel and the Erythromycin becoming part of a fermentation mixture used in making alcohol, wherein the vessel is susceptible to lactic acid bacteria, and wherein the addition of the minimum inhibitory concentration of Erythromycin to the vessel controls the growth of lactic acid bacteria.   
     
     
         12 . The method of  claim 1 , wherein the concentration of Erythromycin ranges from at least 0.5 ppm to about 6 ppm of the fermentation mixture 
     
     
         13 . The method of  claim 11 , wherein the vessel is a fermentation tank and the antibiotic is introduced therein. 
     
     
         14 . The method of  claim 11 , wherein the vessel is a yeast propagation tank and the antibiotic is introduced therein.