Materials: E coli strain DH5a (deoR endA1 gyrA96 hsdR17 supE44 thi1 recA1 lacZM15) (Takara) and B subtilis WB800N (nprE aprE epr bpr mpr:: ble nprB:: ∆vpr wprA:: hyg cm:: neo; NeoR) were used as hosts for the expression of the bacillopeptidase gene.