Antibacterial Spectrum and MICs of Pentocin ZFM94

The antibacterial spectrum of pentocin ZFM94 after purification was detected by the agar well-diffusion method (22). Soft agar of each medium was inoculated with 10⁶ colony-forming units (CFU)/ml of each indicator strain (Table 1) and mixed well, and 8 mm diameter wells were punched with Oxford Cups in the plates. Every well was filled with 100 μl of 10 μm pentocin ZFM94, and the plates were incubated overnight at 37°C. The diameter of the inhibition zones (mm) around the wells was measured.

According to the results of the antibacterial spectrum, MICs of pentocin ZFM94 on S. aureus D48, Micrococcus luteus 10209, and E. coli DH5α were determined by tube method (23). The concentration gradient was 0, 0.10, 0.20, 0.50, 0.875, 1.75, 2.00, 2.50, 3.00, and 10.00 μm. The absorbance was measured by an ultraviolet spectrophotometer (OLYMPUS, Japan). Each concentration was carried out in triplicate.