Abstract:

In order to improve the yield of Douchi fibrinolytic enzyme (DFE) , the full DFE gene encoding was amplified and cloned from the chromosome of Bacillus s叫tilis (B. subtilis) DC12 by means of PCR. The full DFE gene including the promoter, the encoding sequence and the 3'UTR was then inserted into the Escherichia coli-B. subtilis shuttle vector pBE3 and chemically transformed into B. subtilis WB800 to construct the recombinant expression strain. The results show that DFE gene is successfully expressed under the driving of its own promoter in B.subtilis WB800 and secreted into the medium , and that , after the cultivation of recombinant strain for 30 h , the activity of fibrinolytic enzyme in the supematant is as high as 690U/mL.

Key words: Douchi fibrinolytic enzyme, Bacillus subtilis, gene cloning, expression