Ethanol fermentation using oxidation reduction potential

Abstract

A process to improve ethanol yield, decrease fermentation time and reduce byproduct formation by monitoring and controlling oxidation reduction potential (redox) of the fermentor is disclosed.

1 . An anaerobic fermentation system to produce ethanol, which monitors controls or adjusts the oxidation reduction potential in order to attain maximum ethanol yields and/or productivity.  
   
   
       2 . The process as defined in  claim 1  wherein the ethanol producing oxidation reduction potential is controlled within the limits of −250 millivolts to +50 millivolts.  
   
   
       3 . The process according to  claim 1 , wherein either anhydrous ammonia or aqueous ammonia is substituted for sodium hydroxide, in the form of soda ash or caustic solution.  
   
   
       4 . The process according to  claim 2 , wherein either anhydrous ammonia or aqueous ammonia is substituted for sodium hydroxide, in the form of soda ash or caustic solution.  
   
   
       5 . The process according to  claim 1 , wherein sulfite, bi-sulfite or sulfur dioxide is oxidized or removed to elevate oxidation reduction potential.  
   
   
       6 . The process according to  claim 2 , wherein sulfite, bi-sulfite or sulfur dioxide is oxidized or removed to elevate oxidation reduction potential.  
   
   
       7 . The process according to  claim 1 , wherein air or oxygen is sparged in the feed to the fermentation liquid prior to raise the oxidation reduction potential.  
   
   
       8 . The process according to  claim 2 , wherein air or oxygen is sparged in the feed to the fermentation liquid prior to raise the oxidation reduction potential.  
   
   
       9 . The process according to  claim 1 , wherein air or oxygen is sparged directly into the fermentor.  
   
   
       10 . The process according to  claim 2 , wherein air or oxygen is sparged directly into the fermentor.  
   
   
       11 . The process according with  claim 1  wherein an oxidant, such as hydrogen peroxide, is added to the fermentation liquid in order to raise the oxidation reduction potential.  
   
   
       12 . The process according with  claim 2  wherein an oxidant, such as hydrogen peroxide, is added to the fermentation liquid in order to raise the oxidation reduction potential.  
   
   
       13 . The process according to  claim 1  wherein the yeast used for ethanol fermentation is  Saccharomyces Cerevisiae.    
   
   
       14 . The process according to  claim 2  wherein the yeast used for ethanol fermentation is  Saccharomyces Cerevisiae.    
   
   
       15 . The process according to  claim 1  wherein the fermentor is in the continuous or batch mode.  
   
   
       16 . The process according to  claim 2  wherein the fermentor is in the continuous or batch mode.  
   
   
       17 . A process according to  claim 1  wherein the yeast viability count is maintained within certain limits by adjusting the oxidation reduction potential.  
   
   
       18 . A process according to  claim 2  wherein the yeast viability count is maintained within certain limits by adjusting the oxidation reduction potential.  
   
   
       19 . A process according to  claim 1  wherein the residual starch content of the mash is reduced by optimizing the oxidation reduction potential.  
   
   
       20 . A process according to  claim 2  wherein the residual starch content of the mash is reduced by optimizing the oxidation reduction potential.  
   
   
       21 . A process for efficiently producing ethanol through application of anaerobic fermentation comprising: 
 a. providing a closed vessel having both an inlet and outlet, and at least one feed inlet for introducing of fermentable mash into the vessel;    b. said fermentable mash having a percentage of ingredients selected from the group including at least one of corn, milo, barley, wheat, oats, sugar cane, and molasses;    c. said fermentable mash including water in an amount between about 55% to 90% by weight;    d. adding an enzyme into the mash-water mixture to initiate the enzymatic breakdown of the starch content of the mash;    e. adding a yeast into the mixture to further initiate the fermentation process;    f. aerating the fermenting mash in the vessel through the addition of pressurized air or oxygen into the contained mash;    g. continuing the aeration of the aqueous mash solution in the closed vessel and determining the oxidation-reduction potential of the fermenting mash and maintaining a voltage potential between about −250 millivolts to +50 millivolts to attain the most efficient fermentation of the mash to achieve the maximum ethanol yield.    
   
   
       22 . The process of  claim 21  wherein the oxidation-reduction potential of the fermentable mash is elevated in ph through reductant substitution by decreasing of ammonia through the addition of a caustic solution.  
   
   
       23 . The process of  claim 21  wherein the sulfite, bi-sulfite or sulfur dioxide in the mash are oxidized through said addition of air or oxygen to elevate the oxidation-reduction potential of the fermentable mash.  
   
   
       24 . The process of  claim 21  wherein an oxidant, such as hydrogen peroxide, is added to the fermentable mash in order to raise the oxidation-reduction potential of the fermentable mash.