Process for the simultaneous production of xylitol and ethanol
First Claim
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1. A process for the simultaneous production of xylitol and ethanol from a hydrolyzed lignocellulose-containing material, comprisingproviding a starting material of hydrolyzed lignocellulose-containing material comprising xylose and glucose in aqueous solution, wherein xylose content is 50-300 g/l;
- fermenting said starting material with a yeast strain which is capable of converting xylose to xylitol and glucose present to ethanol to form a fermented product comprising xylitol, ethanol and yeast, wherein during fermentation the xylose in the starting material is converted to xylitol and the glucose in the starting material is converted to ethanol and 22.3 g/l to 51.2 g/l of ethanol is produced in the fermentation solution;
recovering the resulting ethanol by distillation of the fermentation solution to obtain a distillate with ethanol and a remaining solution; and
recovering xylitol from the remaining solution by chromatographic separation.
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Abstract
The invention relates to a process for the simultaneous production of xylitol and ethanol from a hydrolyzed lignocellulose-containing material starting. The starting material is fermented with a yeast strain, the ethanol produced is recovered, a chromatographic separation is carried out on the remaining xylitol solution, and pure xylitol is crystallized.
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Citations
24 Claims
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1. A process for the simultaneous production of xylitol and ethanol from a hydrolyzed lignocellulose-containing material, comprising
providing a starting material of hydrolyzed lignocellulose-containing material comprising xylose and glucose in aqueous solution, wherein xylose content is 50-300 g/l; -
fermenting said starting material with a yeast strain which is capable of converting xylose to xylitol and glucose present to ethanol to form a fermented product comprising xylitol, ethanol and yeast, wherein during fermentation the xylose in the starting material is converted to xylitol and the glucose in the starting material is converted to ethanol and 22.3 g/l to 51.2 g/l of ethanol is produced in the fermentation solution;
recovering the resulting ethanol by distillation of the fermentation solution to obtain a distillate with ethanol and a remaining solution; and
recovering xylitol from the remaining solution by chromatographic separation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A process for the simultaneous production of xylitol and ethanol from a hydrolyzed lignocellulose-containing material, wherein lignocellulose-containing material hydrolyzed is selected from the group consisting of softwood, birch, beech, poplar, alder, plants, plant constituents, straw, hulls of wheat, corn, oat, barley, corn cobs, corn stems, nutshells, bagasse, cottonseed bran, wood chips, sawdust, sulphite spent liquor from woodpulp processing, waste from paper processing, and waste from woodpulp processing, comprising:
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providing a starting material of hydrolyzed lignocellulose-containing material comprising xylose and glucose in aqueous solution, wherein xylose content is 50-300 g/l;
fermenting said starting material to produce a fermented solution with a yeast capable of converting xylose present in the starting material to xylitol and glucose present in the starting material to ethanol, said yeast selected from the group consisting of a yeast of the genera Candida, Pichia, Pachysolen, and Debaryomyces, said fermenting comprising reducing said xylose to xylitol and said glucose to ethanol, and said fermented solution comprising xylitol, ethanol, and spent yeast;
wherein during fermentation the xylose in the starting material is converted to xylitol glucose in the starting material is converted to ethanol and 22.3 g/l to 51.2 g/l of ethanol is produced into the fermentation solution;
separating a substantial portion of said spent yeast from said fermented solution to produce a substantially clarified solution comprising ethanol and xylitol, said clarified solution comprising substantially less spent yeast by weight on a dry solids (substance) basis than said spent yeast in said fermented solution, and said separating comprising at least one separating method selected from group consisting of filtration, centrifugation and decanting;
recovering ethanol by distillation to obtain a distillate with ethanol and a remaining solution;
recovering xylitol from the remaining solution by chromatographic separation; and
crystallizing said xylitol to produce xylitol crystals. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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Specification