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Updated: Sep 29, 2026

A New Screening Method for the Directed Evolution of Thermostable Bacteriolytic Enzymes
Published on: November 7, 2012
Characterization of a thermostable levansucrase from Bacillus sp. TH4-2 capable of producing high molecular weight
Youssef Ben Ammar1, Takayoshi Matsubara, Kazuo Ito
1Laboratory of Enzyme Chemistry, Faculty of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan. youseff76@hotmail.com
Abstract:
A thermoactive and thermostable levansucrase was purified from a newly isolated thermophilic Bacillus sp. from Thailand soil. The purification was achieved by alcohol precipitation, DEAE-Cellulose and gel filtration chromatographies. The enzyme was purified to homogeneity as determined by SDS-PAGE, and had a molecular mass of 56 kDa. This levansucrase has some interesting characteristics regarding its optimum temperature and heat stability. The optimum temperature and pH were 60 degrees C and 6.0, respectively. The enzyme was completely stable after treatment at 50 degrees C for more than 1 h, and its activity increased four folds in the presence of 5 mM Fe(2+). The optimum temperature for levan production was 50 degrees C. Contrary to other levansucrases, the one presented in this study is able to produce high molecular weight levan at 50 degrees C.
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