Beta-xylosidase for conversion of plant cell wall carbohydrates to simple sugars
Xylose-containing plant material may be hydrolyzed to xylose using a β-D-xylosidase which exhibits unexpectedly high activity. The enzyme has a kcat value for catalysis of approximately 185 sec−1 for 1,4-β-D-xylobiose (X2) when measured at a pH of 5.3 and a temperature of 25° C.; this is at least 10-fold greater than reported for other xylosidases at 25° C. and their optimal pH. The enzyme also has an isoelectric point of approximately 4.4. When reacted at a pH between about 4.5 and about 7.7, the β-D-xylosidase exhibits surprisingly high activity for hydrolyzing xylose-containing plant materials to xylose. The xylose released from plant materials may then be converted to other secondary products such as ethanol by fermentation or other reaction. This β-D-xylosidase may be used alone or in combination with other hydrolytic or xylanolytic enzymes for treatment of lignocellulosic or hemicellulosic plant materials or plant material hydrolysates or xylooligosaccharides.
The United States of America as represented by the Secretary of Agriculture
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Michael A. Douglas B. Terence R. Christopher A. Xin Liang
Cotta Jordan Whitehead Dunlap Li