Patent ID: 7109005
Filing Date: 2006-09-19
Classification: B01D,C12P,Y02E,Y10S

Abstract:
1. A method of processing lignocellulose-containing material from xylan-containing biomass comprising pentoses and hexoses to produce ethanol and xylitol, comprising the steps of: partially hydrolyzing lignocellulose-containing material in xylan-containing matter in biomass comprising pentoses and hexoses to produce a partially hydrolyzed solution comprising an extracted biomass and solubles; the solubles comprising free pentoses, hexoses, pentosans, hexosans and residue; and the extracted biomass comprising hexosans, pentosans and solids; said lignocellulose-containing material comprising at least one lignocellulosic material selected from the group consisting of cellulose and hemicellulose; said pentoses comprising at least one pentose-containing material selected from the group consisting of xylose and arabinose; said hexoses comprising at least one hexose-containing material selected from the group consisting of glucose, galactose, rhamnose and mannose; said xylan-containing matter selected from the group consisting of wood, hardwood, softwood, plants, plant constituents, grains particulates of grain stems, shells, corn cobs, cornstraw, corn fiber, nutshells, almond shells, coconut shells, bagasse, cotton seed bran, cotton seed skins, wood chips, sawdust, woodpulp, processed paper, spent sulphite liquor, spent liquor from hardwood pulping, spent liquor from paper processing, spent liquor from woodpulp processing, sulphite cooking liquor, and liquids derived from wood, hardwood, softwood, plants, plant constituents, grains, particulates of grain, stems, shells, corn cobs, cornstraw, corn fiber, nutshells, almond shells, coconut shells, bagasse, cotton seed bran, cotton seed skins, wood chips, sawdust, woodpulp, and processed paper; separating said partially hydrolyzed solution into an extracted biomass and solubles; said extracted biomass comprising pentosans, hexosans, and solids, said solubles comprising xylose, hexoses, soluble xylans, pentoses, soluble pentosans and hexosans, and residue; hydrolyzing said extracted biomass to produce a hydrolyzed biomass comprising hexoses, pentoses, and hydrolyzed solids, said hydrolyzing converting a substantial amount of said pentosans to pentoses, and said hydrolyzing converting a substantial amount of said hexosans to hexoses; separating said hydrolyzed biomass into a biomass solution and solids, said biomass-solution comprising pentoses and hexoses, said biomass solution comprising a greater concentration of pentoses by weight on a dry substance (solids) basis than said pentoses in said hydrolyzed biomass, said biomass solution comprising a greater concentration of hexoses by weight on a dry substance (solids) basis than said hexoses in said hydrolyzed biomass; fractionating said solubles to separate said solubles into fractions comprising a xylose-rich fraction, a xylose-containing fraction, and a residue fraction, said xylose-rich fraction comprising a higher concentration of xylose by weight on a dry substance (solids) than said xyloses in said solubles, said residue fraction comprising a higher concentration of residue by weight on a dry substance (solids) than said residue in said solubles, said xylose-rich fraction comprising a higher concentration of at least one compound by weight on a dry substance (solids) than said compound in said other fractions, and said compound being selected from the group consisting of xylose, arabinose, mannose, galactose and rhamnose; hydrogenating said xylose-rich fraction to produce hydrogenated xylitol, said hydrogenated xylitol having a greater concentration of xylitol by weight on a dry substance (solids) basis than said xylitols in said solubles; fermenting said xylose-containing fraction and said biomass solution with microbes to produce a fermented solution comprising fermented ethanol and spent microbes, said fermenting comprising converting a substantial amount of said xyloses in said xylose-containing fraction to fermented ethanol and part to xylitol and fermenting a substantial amount of said pentoses and hexoses in said biomass solution to fermented ethanol; and said microbes comprising at least one fermenting microorganism selected from the group consisting of naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi.