High-level extracellular production of recombinant nattokinase in Bacillus subtilis WB800 by multiple tandem promoters.

Our studies demonstrated that NK was efficiently overproduced by tandem promoters in Bacillus subtilis. The highest fibrinolytic activity was promoted by PHpaII-PHpaII-PP43, which was much higher than that had been reported in previous studies. These multiple tandem promoters were used successfully to control NK expression and might be useful for improving the expression level of the other genes.