Catalytic Properties of Bacillus megaterium Amylase

Abstract

AbstractA new amylolytic enzyme from Bacillus megaterium is described, which is produced as a trace contaminant in a complex protein mixture, with β‐amylase as the major enzyme. By genetic engineering, the productivity could be increased by a factor 10000, and the enzyme is free of other amylases. Compared to pullulanase, which catalyses pullulan degradation to maltotriose, B. megaterium amylase (BMA) does not attack 1,6‐linkages and hydrolyses pullulan exclusively to panose. Furthermore, it hydrolyses crosslinked Phadebas starch, used for determination of α‐amylases and it also catalyses transfer reactions. Those are strongly enhanced in presence of suitable acceptors, which can be sugar molecules with the same configuration as dextrose in C2, C3, C4‐position. In the industrial dextrose process, about 1% of oligosaccharides remains from starch which is difficult to be hydrolysed, thus reducing yield and quality of the final product. The structure elucidation showed 35% 1,6‐linkages being present. These oligosaccharides can be degraded and eliminated by BMA through panosyl transfer to dextrose, under formation of 63‐α‐glucosylmaltotriose, which is degraded by glucoamylase to dextrose.