PURIFICATION AND CHARACTERIZATION OF BETA-AMYLASE FROM BACILLUS-POLYMYXA NO-26-1

An extracellular beta-amylase, which was easily adsorbable onto raw co rn starch, was purified 22.5-fold from a new isolate of Bacillus polym yxa No 26-1 with a M(r) of 53 kDa and pI of 9.1. The optimum temperatu re was 45 degrees C and pH 5.5 for raw corn starch. Thermal stability at 40 degrees C and pH stability at 5.0-8.5 were shown. The degradatio n of raw starch by beta-amylase was greatly stimulated by pullulanase addition. Scanning electron micrographs revealed that starch granule d egradation by the enzyme alone occured at the equatorial grooves of le cticular granules. Corn starch granules hydrolyzed by beta-amylase had large holes on granule surfaces.