Direct fermentation of D-xylose to ethanol by a xylose-fermenting yeast mutant
AssigneePurdue Research Foundation
InventorCheng-Shung Gong
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Abstract
A process for obtaining ethanol directly from D-xylose through fermentation of D-xylose by xylose-fermenting yeast mutants. The process provides for obtaining ethanol from hemicellulose hydrolyzates through yeast fermentation of D-xylose to ethanol. Furthermore, the process also provides for obtaining ethanol from a mixture of cellulose and hemicellulose hydrolyzates through yeast fermentation of D-glucose and D-xylose directly and simultaneously to ethanol.
Claims18
A process for the direct fermentation of D-xylose to ethanol which comprises inoculating a medium comprising growth nutrients and D-xylose with a yeast mutant of the strain Candida sp. having an ability to ferment D-xylose to ethanol with a bioconversion yield of at least 80%, permitting the inoculated medium to ferment for a period of time sufficient to achieve a conversion of D-xylose to ethanol of at least 80% and recovering the ethanol so produced as product.
A process for the direct fermentation of D-xylose to ethanol which comprises inoculating a medium comprising growth nutrients and D-xylose in an amount of from 1 to about 40% by weight/volume of said medium with a yeast mutant of the strain Candida sp. having an ability to ferment D-xylose to ethanol with a bioconversion yield of at least 80%, fermenting the innoculated medium at a temperature ranging from about 22.degree. to about 40.degree. C. and a pH ranging from about 4 to about 8 for a period of time sufficient to achieve at least an 80% conversion of the D-xylose to ethanol, and recovering the ethanol so produced as product.
A process for the production of ethanol directly and simultaneously from D-glucose and D-xylose which comprises inoculating a medium comprising growth nutrients, D-glucose and D-xylose with a yeast mutant of the strain Candida sp. having an ability to ferment D-glucose and D-xylose to ethanol with a bioconversion yield of at least 80%, fermenting the innoculated medium for a period of time sufficient to achieve a conversion of D-xylose to ethanol of at least 80% and recovering the ethanol so produced as product.
Dependencies are inferred from the claim text.