The results of three-step purification procedure and molecular mass determination were shown in Fig. 3. At the final step of the purification process four single peaks were obtained (Fig. 3c). The lyophilized sample of the third peak at 6.4 min (bacteriocin F1) showed significant antibacterial activity against E. coli (MIC 62.5 µg/mL), which was significantly stronger than that of the maximum antimicrobial activity of the 72-h cell-free supernatant (MIC 15.6 mg/mL).