Process for the simultaneous production of xylitol and ethanol

A method of processing lignocellulose-containing material from xylan-containing biomass comprising pentoses and hexoses to produce ethanol and xylitol, comprising the steps of:

• hydrolyzing lignocellulose-containing material from xylan-containing biomass comprising pentoses and hexoses to produce a hydrolyzed solution comprising free pentoses and hexoses;
• said lignocellulose-containing material comprising at least one lignocellulosic material selected from the group consisting of cellulose, hemicellulose,
• said pentose comprising at least one pentose-containing material selected form the group consisting of xylose and arabinose;
• said hexose comprising at least one hexose-containing material selected from the group consisting of glucose, galactose, rhamnose, mannose, and other monosaccharides;
• said xylan-containing matter selected from the group consisting of wood, hardwood as alder, aspen, birch, beech, maple, eucalyptus, willow, and poplar, softwood as pine and spruce, plants, plant constituents, grain as wheat, barley, rice, rye and oat particulates of grains as straw, hulls, husks, stems, fiber, shells , corn cobs, corn stems, corn fibres, 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 any of the preceding;
• fermenting said hydrolyzed solution with microbes to produce a fermented solution comprising fermented ethanol, fermented xylitol, fermented xylose, and spent microbes, said fermenting comprising converting a substantial amount of said hexose in said hydrolyzed solution to fermented ethanol and reducing a substantial amount of said pentose in said hydrolyzed solution to fermented xylitol, fermented ethanol solution and fermented xylose;
• said microbes comprising at least one fermenting microorganism selected form the group consisting of naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi;
• and
• distilling fermented liquid derived from said fermented solution to produce distilled ethanol and a distilled solution comprising distilled xylitol solution, distilled xylose and spent microbes, said distilled ethanol comprising a greater concentration of distilled ethanol by weight on a liquid basis than said fermented ethanol in said fermented solution, said distilled solution having a greater concentration of distilled xylitol solution by weight on a dry substance (solids) basis than said fermented xylitol solution in said fermented solution;
• and
• separating said distilled solution by fractionating said distilled solution into fractions comprising a separated xylitol-producing fraction and a separated xylose fraction, said separated xylitol-producing fraction comprising a greater concentration of xylitol-producing solution by weight on a dry substance (solids) basis than said distilled xylitol-producing solution in said distilled solution.

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 from xylan-containing matter in biomass comprising pentoses and hexoses to produce a partially hydrolyzed solution comprising free pentoses and hexoses, pentosans, and hexosans;
• said lignocellulose-containing material comprising at least one lignocellulosic material selected from the group consisting of cellulose, hemicellulose;
• said pentoses comprising at least one pentose-containing material selected form 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 as alder, aspen, birch, beech, eucalyptus, poplar, willow and maple, softwood as pine and spruce, willow, plants, plant constituents, grains as wheat, barley, rye, rice and oat particulates of grain as straw, hulls, husks, fiber, 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 any of the preceding;
• separating said partially hydrolyzed solution into an extracted biomass and solubles, said extracted mass comprising pentosans and hexosans, and solids, said solubles comprising xylose, soluble xylans, pentoses, soluble pentosans and residue;
• hydrolyzing said extracted biomass to produce a hydrolyzed biomass comprising hydrolyzed hexoses, hydrolyzed 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 separated biomass solution and solids, said separated biomass solution comprising pentoses and hexoses, said separated biomass solution comprising a greater concentration of pentoses by weight on a dry substance (solids) basis than said hydrolyzed pentoses in said hydrolyzed biomass, said separated biomass solution comprising a greater concentration of hexoses by weight on a dry substance (solids) basis than said hydrolyzed hexoses in said hydrolyzed biomass;
• fractionating said solubles to separate said solubles into fractions comprising a xylose-rich fraction, and a residue (residual) 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, xylitol, arabinose, mannose, and galactose and rhanmose;
• 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 separated 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 reducing a substantial amount of said pentoses and hexoses in said separated biomass solution to fermented ethanol;
• and
• said microbes comprising at least one fermenting microorganism selected form the group consisting of naturally occurring bacteria, recombinant bacteria, naturally occurring yeast, recombinant yeast, and fungi.