Cloning of aBacillussp. BP-23 gene encoding a xylanase with high activity against aryl xylosides

The xynB gene encoding a xylanase from the recently isolated Bacillus sp. strain BP-23 has been cloned and expressed in Escherichia coli. The enzyme produced in this host shows a molecular size of 41 kDa and a pI of 4.5. The pH and temperature at which the highest activity was found were 5.5 and 50 degrees C respectively. Crude xylanase B showed activity on xylan, aryl xylosides, xylotetraose and xylotriose, while xylobiose was not hydrolyzed by the enzyme. Xylanase B showed high specific activity on aryl xylosides, probably as a result of the transxylosidase activity detected.