Chinese Journal of Biotechnology 2016;32(9):1233-1242

doi:10.13345/j.cjb.150527

Stability enhancement of urethanase from Lysinibacillus fusiformis by site-directed mutagenesis.

Xiaohui LIU 1 ; Fang FANG 1 ; Xiaole XIA 1 ; Guocheng DU 2 ; Jian CHEN 1

Affiliations

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Keywords

enzyme stability; ethyl carbamate; site-directed mutagenesis; urethanase

Country

China

Language

Chinese

Abstract

Ethyl carbamate as a potential carcinogen commonly exists in traditional fermented foods and beverages. Enzymatic removal of ethyl carbamate from fermented foods and beverages is an efficient and safe method. In this study, we mutated urethanase from Lysinibacillus fusiformis SC02 on the Q328 site through computer aided design approaches. The half-life of resulting mutants Q328C and Q328V was detected to be 7.46 and 1.96 folds higher than that of the original enzyme, and Q328R presented better thermal-tolerance than the original urethanase when incubated at high temperature. The tolerance of Q328C to ethanol and acid also increased when compared with that of the original enzyme. The stability and tolerance to acid and ethanol of urethanase could be improved by modification on its Q328 site.