Research articles
ScienceAsia (): 17-23 |doi:
10.2306/scienceasia1513-1874...017
Over-expression and characterization of the alkalophilic, organic solvent-tolerant, and thermotolerant endo-1,4-β-mannanase from Bacillus licheniformis isolate THCM 3.1
Pornpimon Kanjanavasa, Paisarn Khawsaka, Arda Pakpitcharoena, Supatra Areekita, Thayat Sriyaphaia, Khajeenart Pothivejkulb, Somchai Santiwatanakulc, Kenji Matsuid, Tadahiko Kajiwarad, Kosum Chansiria,*
ABSTRACT: Gene encoding for endo-1,4-β-mannanase (EC 3.2.1.78) from Bacillus licheniformis THCM 3.1 was cloned and over-expressed in pET 100/D TOPO vector. The molecular weight of the purified enzyme was about 40 kDa. This enzyme had an optimum pH of 9 and an optimum temperature of 45 °C and retained up to 77% of its activity after incubation for 48 h. The activity of the enzyme was inhibited by 10 mM of Pb2+, Ag+, Fe3+, Sn2+, Cu2+, and EDTA. Although partially inhibited, the enzyme retained much of its activity when the reaction solution was mixed with 15% (v/v) of the organic solvents acetone, toluene, benzene, dimethyl sulphoxide, 2-propanol, acetonitrile, or cyclohexane.
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a |
Department of Biochemistry, Faculty of Medicine, Srinakharinwirot University, Bangkok 10110, Thailand |
b |
Department of Biology, Faculty of Sciences, Srinakharinwirot University, Bangkok 10110, Thailand |
c |
Department of Pathology, Faculty of Medicine, Srinakharinwirot University, Bangkok 10110, Thailand |
d |
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan |
* Corresponding author, E-mail: kosum@swu.ac.th
Received 29 Apr 2008, Accepted 6 Feb 2009
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