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Lipase B from Candida antarctica (CalB) showing several excellent characteristics such as high stereo-selectivity and stability in organic solvent has attracted much attention for various enzymatic bioconversion reactions [1]. To apply lipase to commercial process, the thermal stability is one of the prerequisites. In this study, the thermal stability of CalB was improved through increasing the number of disulfide bridges based on B-factor and MODIP program. Among amino acid pairs showing highest probability to form disulfide bridges in grade A of MODIP, four candidates (S50-A273, Q156-L163, A162-K308, N169-F304) were selected based on B-factor of its residues. Four double CalB mutants were constructed and evaluated their thermal stability. As a result, CalB A162C-K308C mutant showed greatly improved thermal stability compared to its wild type. The residual activity of CalB A162C_K308C was 3.2 times greater than that of CalB wild type at 50oC after incubating 150 minutes. Increase of 8.5oC in the aspect of temperature at which 50% its activity remaining after 60 minute incubation (T50 60) was observed for CalB A162C_K308C mutant compared with that of CalB wild type. This mutant can be anticipated to apply for commercial purposes. References:1. Stefan Lutz, Engineering Lipase B from Candida Antarctica (2004), Tetrahedron:Asymmetry 15, 2743-2748.