PURIFICATION AND CHARACTERIZATION OF A XYLANASE AND AN ARABINOFURANOSIDASE FROM BACILLUS-POLYMYXA

Two hemicellulases from Bacillus polymyxa were purified and characteri zed: a xylanase with a molecular mass of 61 kD and pI of 4.7 and an ar abinofuranosidase with a molecular mass of 166 kD and pI of 4.7. The x ylanase, which showed increased thermostability in the presence of MgC l2, showed a typical endo-action mode on xylans from several sources. The arabinofuranosidase was only active on (1-->5)-alpha-L-arabinoolig osaccharides but not on linear (1-->5>)-alpha-L-arabinan, arabinogalac tan, and arabinoxylan. Ho,wever, it was able to release arabinose from arabinoxylan when an active endoxylanase was also present in hydrolys is assays.