| Title |
Characterization, Gene Cloning, and Heterologous Expression of β-Mannanase from a Thermophilic Bacillus subtilis |
| Author |
Pijug Summpunn1,2, Suttidarak Chaijan2, Duangnate Isarangkul2, Suthep Wiyakrutta2, and Vithaya Meevootisom2* |
| Address |
1Department of Biotechnology, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand, 2Department of Microbiology, Faculty of Science, Mahidol University, Rama VI Rd., Bangkok 10400, Thailand |
| Bibliography |
Journal of Microbiology, 49(1),86-93, 2011,
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| DOI |
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| Key Words |
β-mannanase, Bacillus subtilis, characterization, gene expression, thermophilic |
| Abstract |
Bacillus subtilis BCC41051 producing a thermostable β-mannanase was isolated from soybean meal-enriched soil and was unexpectedly found to be thermophilic in nature. The extracellular β-mannanase (ManA) produced was hydrophilic, as it was not precipitated even with ammonium sulfate at 80% saturation. The estimated molecular weight of ManA was 38.0 kDa by SDS-PAGE with a pI value of 5.3. Optimal pH and temperature for mannan-hydrolyzing activity was 7.0 and 60°C, respectively. The enzyme was stable over a pH range of 5.0-11.5, and at temperatures of up to 60°C for 30 min, with more than 80% of its activity retained.
ManA was strongly inhibited by Hg2+ (1 mM), but was sensitive to other divalent ions to a lesser degree. The gene of ManA encoded a protein of 362 amino acid residues, with the first 26 residues identified as a signal peptide. High expression of recombinant ManA was achieved in both Escherichia coli BL21 (DE3) (415.18 U/ml) and B. megaterium UNcat (359 U/ml). |
