Enhancement of surfactin production of Bacillus subtilis fmbR by replacement of the native promoter with the Pspac promoter.

Bacillus subtilis fmbR-1 was obtained from wild-type B. subtilis fmbR by replacement of the native promoter of the surfactin operon with the inducible promoter Pspac. The recombinant B. subtilis fmbR-1 produced more antibacterial substances than the wild-type strain. The overproducing phenotype was related to the enhancement of antagonistic activities against Bacillus cereus. HPLC peaks of surfactin for recombinant fmbR-1 showed patterns of lipopeptides similar to those of the wild-type strain, and surfactin production of the recombinant fmbR-1 was up to about fivefold greater than that of the wild-type strain without induction by isopropyl beta--1-thiogalactopyranoside. However, the production of surfactin increased to about 10-fold more than that of the wild-type strain when it was induced by isopropyl beta--1-thiogalactopyranoside.