American Journal of Biochemistry and Biotechnology

Identification a Novel Raw-Starch-Degrading-α-Amylase from a Tropical Marine Bacterium

Zeily Nurachman, Alfredo Kono, Ocky Karna Radjasa and Dessy Natalia

DOI : 10.3844/ajbbsp.2010.300.306

American Journal of Biochemistry and Biotechnology

Volume 6, Issue 4

Pages 300-306

Abstract

Problem statement: Bacteria from the surface of the tropical marine hard coral Acropora sp. were screened for producing raw-starch-degrading-α-amylase. Approach: Based on its 16s rDNA sequence, a bacterium that produced the highest amylolitic activity was identified as Bacillus amyloliquifaciens ABBD. The bacterial isolate secreted a α-amylase extracellularly and then the enzyme was partially purified by ammonium sulfate precipitation followed by anion exchange chromatography. Results: Electrophoresis results both SDS-PAGE and native PAGE suggested that the enzyme was a heterodimeric protein (97 kDa) consisting of 45 and 55 kDa subunits. The α-amylase had an optimum pH of 7.0 and temperature of 60°C. More than 80% activity of the enzyme was retained under high salt conditions (up to 20% NaCl). The enzyme remained stable at 50°C for 1 h. Starch hydrolysis by the enzyme at 70°C yielded oligosaccharides (G2-G4) and at room temperature yielded glucose/maltose (G1 and G2). Conclusion: The B. amyloliquifaciens ABBD α-amylase was capable of degrading various raw starch granules from corn, rice, cassava and sago at room temperature.

Copyright

© 2010 Zeily Nurachman, Alfredo Kono, Ocky Karna Radjasa and Dessy Natalia. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.