| Title |
Characterization of the Bacillus subtilis WL-3 Mannanase from a Recombinant Escherichia coli |
| Author |
Ki-Hong Yoon1,2*, Seesub Chung1, and Byung-Lak Lim3 |
| Address |
1School of Food Science and Biotechnology, Woosong University, Daejeon 300-718, Republic of Korea, 2Bioresouce and Application Research Center, Woosong University, Daejeon 300-718, Republic of Korea, 3H&BT Korea Co. Ltd., Iksan 570-982, Republic of Korea |
| Bibliography |
Journal of Microbiology, 46(3),344-349, 2008,
|
| DOI |
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| Key Words |
Bacillus subtilis WL-3, characterization, mannanase, recombinant Escherichia coli |
| Abstract |
A mannanase was purified from a cell-free extract of the recombinant Escherichia coli carrying a Bacillus subtilis WL-3 mannanase gene. The molecular mass of the purified mannanase was 38 kDa as estimated by SDS-PAGE. Optimal conditions for the purified enzyme occurred at pH 6.0 and 60°C. The specific activity of the purified mannanase was 5,900 U/mg on locust bean gum (LBG) galactomannan at pH 6.0 and 50°C. The activity of the enzyme was slightly inhibited by Mg2+, Ca2+, EDTA and SDS, and noticeably enhanced by Fe2+. When the enzyme was incubated at 4°C for one day in the presence of 3 mM Fe2+, no residual activity of the mannanase was observed. The enzyme showed higher activity on LBG and konjac glucomannan than on guar gum galactomannan. Furthermore, it could hydrolyze xylans such as arabinoxylan, birchwood xylan and oat spelt xylan, while it did not exhibit any activities towards carboxymethylcellulose and para-nitrophenyl-β-mannopyranoside. The predominant products resulting from the mannanase hydrolysis were mannose, mannobiose and mannotriose for LBG or mannooligosaccharides including mannotriose, mannotetraose, mannopentaose and mannohexaose. The enzyme could hydrolyze mannooligosaccharides larger than mannobiose. |
