ACTION PATTERN OF BACILLUS LICHENIFORMIS ALPHA‐AMYLASE ON ORDINARY, WAXY, AND HIGH‐AMYLOSE CORN STARCHES AND THEIR HYDROXYPROPYL DERIVATIVES

The action of thermally stable alpha-amylase from Bacillus licheniformis on ordinary, waxy and high-amylose corn starches and their hydroxypropyl derivatives gave distinctive patterns of malto-oligosaccharide products that were dependent on conversion time. These alpha-amylolysis patterns of the various starches were derived from high performance liquid chromatographic analyses of the oligosaccharide compositions produced at various levels of hydrolysis. The products from amylolysis at high substrate concentrations (20–30%) and elevated temperature (95°C) suggest an endo-specific hydrolysis of the amylose and amylopectin chains to give a trio product-specificity for the formation of DP5, DP3, and DP2 oligosaccharides. These results confirm and expand the studies by Saito (1973) and Nakakuki et al. (1984), who found that B. licheniformis amylase degraded a 1% solution of short-chain amylose at 40° to give mainly DP5 and DP3 oligomers. The hydroxypropyl groups on ordinary, waxy and high-amylose starch derivatives greatly hindered alpha-amylolysis, but the action patterns were essentially the same.