OnLine Journal of Biological Sciences

Characteristics of a Novel Highly Thermostable and Extremely Thermophilic Alkalitolerant Amylase from Hyperthermophilic Bacillus Strain HUTBS71

Farouk Al-Quadan, Hazem Akel and Rasha Natshi

DOI : 10.3844/ojbsci.2009.67.74

OnLine Journal of Biological Sciences

Volume 9, Issue 3

Pages 67-74


Problem statement: This study reported the purification and characterization of a novel highly thermostable alkaline amylase from a newly isolated Bacillus strain HUTBS71. Approach: The enzyme was purified using ammonium sulfate precipitation, ion exchange and gel filtration chromatography. Results: Maximum amylase activity (72 U mL-1) was obtained at 100°C after 10 min of incubation. The enzyme was purified 24 fold with 12.5% yield and showed a monomer band with a molecular weight of 58.8 kDa by SDS-PAGE. This enzyme exhibited maximum activity at pH and temperature, 7.8 and 100°C, respectively. It performed stability over a broad range of pH and temperature, 5.2-10.0 and 80-115°C, respectively. The half-life of the enzyme at 90 and 100°C was estimated to be 3 h. The activation energy of denaturation of purified enzyme was 2.53 kJ moL-1. The enzyme was activated by 5 mM of CoCl2, MgSO4, MnCl2, ZnSO4 and MnSO4 (relative activity was 133, 126, 133, 106.6 and 103%, respectively). It was strongly inhibited by CuSO4 and CdCl2 but less affected by NaCl, CaCl2, FeCl3, ZnCl2 and EDTA. Conclusion: The present purified amylase therefore could be defined as a highly thermostable, extremely hyperthermophilic and alkalitolerant with new properties make the present enzyme applicable for many starch processing and food industries.


© 2009 Farouk Al-Quadan, Hazem Akel and Rasha Natshi. 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.