Patent ID: 7488390
Filing Date: 2009-02-10
Classification: A23J,B02B,B02C,C12P,Y02E

Abstract:
1. A process for refining a plant material, the process comprising: (a) providing a plant material comprising: (i) starch; and (ii) fiber comprising cellulose, hemicellulose, lignin, and pectin; (b) isolating a starch slurry and a fiber slurry from the plant material; (c) converting the starch slurry to a primary glucose solution; (d) adding an effective amount of yeast to the primary glucose solution and fermenting it in a primary fermenter to produce carbon dioxide and a primary fermented stream containing ethanol; (e) heating the fiber slurry in a first reactor to a temperature of about 75 to 125° C. under mild alkaline conditions for a sufficient time to hydrolyze substantially all the hemicellulose and pectin into soluble pentose and hexose sugars; (f) separating the insoluble cellulose and lignin from the pentose and hexose sugar solution and forming a slurry of the cellulose and lignin; (g) adding the pentose and hexose sugar solution to the primary fermenter; (h) heating the slurry of cellulose and lignin in a second reactor to a temperature of about 125 to 160° C. under severe alkaline conditions for a sufficient time to hydrolyze substantially all the lignin into soluble lignin hydrolysates; (i) separating the insoluble cellulose, treating it with an effective amount of enzyme to convert it to a secondary glucose solution; and (j) adding the secondary glucose solution to the primary fermenter.