Method for producing ethanol using raw starch
The present invention relates to methods for producing high levels of alcohol during fermentation of plant material, and to the high alcohol beer produced. The present invention also relates to methods for producing high protein distiller's dried grain from fermentation of plant material, and to the high protein distiller's dried grain produced. The present invention further relates to reduced stack emissions from drying distillation products from the production of ethanol.
1. A method for producing ethanol from ground corn which method comprises:
providing an aqueous composition comprising ground corn sized such that more than 50% of the ground corn passes through a 0.5 mm screen, an fungal acid amylase and a glucoamylase under conditions which produce glucose including a pH of 3 to 6, a temperature of 25° C. to 40° C., and a solids content 20 to 50 weight percent; and
fermenting the glucose in the presence of a yeast and in the absence of added protease, under conditions which produce ethanol wherein said conditions include a pH of 3 to 6 and maintaining a glucose concentration in the aqueous composition of less than 1 weight percent after 12 hours of saccharification and fermentation, wherein said method produces at least 18 volume percent ethanol.
2. The method of claim 1 , wherein the aqueous composition of ground corn, fungal acid amylase and glucoamylase is maintained at a pH of from about 4.0 to 5.0.
3. The method of claim 1 , wherein the amount of said fungal acid amylase to dry solids in said composition ranges from about 0.1 to about 10 fungal acid amylase units per gram of said dry solids.
4. The method of claim 3 , wherein the amount of said glucoamylase to dry solids in said composition ranges from about 0.5 to about 6 glucoamylase units per gram of said dry solids.
5. A method for producing ethanol from ground corn which method comprises:
providing an aqueous composition comprising ground corn sized such that the ground corn passes through a 0.5 mm screen, an fungal acid amylase and a glucoamylase under conditions which produce glucose including a pH of 3 to 6, a temperature of 25° C. to 40° C., and a solids content of 20 to 50 weight percent; and
fermenting the glucose in the presence of a yeast and in the absence of added protease, under conditions which produce ethanol wherein said conditions include a pH of 3 to 6 and maintaining a glucose concentration in the aqueous composition of less than about 2 weight percent;
wherein the production of glucose and the fermentation of glucose to ethanol is conducted in a simultaneous process, and further wherein said method produces at least 18 volume percent ethanol.
6. The method of claim 5 , wherein the aqueous composition of ground corn, fungal acid amylase and glucoamylase is maintained at a pH of from about 4.0 to 5.0.
7. The method of claim 5 , wherein the amount of said fungal acid amylase to dry solids in said composition ranges from about 0.1 to about 10 fungal acid amylase units per gram of said dry solids.
8. The method of claim 5 , wherein the glucose concentration during fermentation is maintained at less than about 1 weight percent.
9. The method of claim 5 , wherein during the production of ethanol, the pH is maintained at 3-4.5 during the first half of the fill cycle and at 4.5-6.0 during the second half of the fill cycle.
10. The method of claim 7 , wherein the amount of said glucoamylase to dry solids in said composition ranges from about 0.5 to about 6 glucoamylase units per gram of said dry solids.
11. A method for producing ethanol from ground corn which method comprises:
providing an aqueous composition comprising ground corn sized such that the ground corn passes through a 0.5 mm screen, an fungal acid amylase and a glucoamylase under conditions which produce glucose wherein said conditions include a pH of 3 to 6, a temperature of 30° C. to 35° C., a solids content of 25 to 45 weight percent, an amount of said fungal amylase to dry solids in said composition which is between 0.1 and 10 fungal acid amylase units per gram of said dry solids, and an amount of said glucoamylase to dry solids in said composition which is between 0.5 and 6 glucoamylase units per gram of said dry solids; and
fermenting the glucose in the presence of a yeast and in the absence of added protease, under conditions which produce ethanol wherein said conditions comprise an initial temperature of about 35° C. which temperature is decreased during fermentation to a temperature of about 30° C., and maintaining a glucose concentration in the aqueous composition of less than 2 weight percent after 12 hours of saccharification and fermentation wherein the production of glucose and the fermentation of glucose to ethanol is conducted in a simultaneous process, and further wherein said method produces at least 18 volume percent ethanol.
12. The process of claim 11 , wherein said process is a continuous process.
13. The process of claim 11 , wherein said process is conducted for about 48 to 96 hours.