Abstract: Chronic heavy use of bactericides could not only induce antibiotic resistance, but also could cause serious environmental and health risks. Thus, it is very important to develop new bactericides that kill pathogens without detectable resistance. In this study, a novel antimicrobial peptide produced by Bacillus pumilus HN-10 was purified consecutively by ammonium sulfate precipitation, macroporous resin AB-8 chromatography, Sephadex G-100 chromatography, and reversed-phase high performance liquid chromatography (RP-HPLC). The antimicrobial activity of the peptide was tested against Trichothecium roseum. The amino acid sequence was analyzed by matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS/MS). The results showed that this peptide was designated as P-1 and its amino acid sequence was G-G-S-G-G-G-S-S-G-G-S-I-G-G-R with a molecular mass of 1 149.14 Da. P-1 exhibited strong antimicrobial activity against T. roseum with a minimum inhibitory concentration of 1 μg/mL. Analysis with the ProtParam software indicated that the theoretical isoelectric point of P-1 was 9.75, with one positive charge. P-1 was proved to be a novel peptide by NCBI database and APD database search with the highest similarity of only 45%.

Key words: antimicrobial peptide, Bacillus pumilus HN-10, characterization and purification, Trichothecium roseum