Abstract:

【Objective】 The components of anti-gram-negative bacteria by the strain CP7 of Paenibacillus polymyxa were purified, and the structure was identified. 【Method】 The antibacterial components from CP7 strain were purified by the solid phase extraction, cation-exchange chromatography, gel-filtration chromatography and HPLC. The components were analyzed with the technique of the ultraviolet-visible spectrum, circular dichroism spectroscopy, IR and MALDI-TOF-TOF-MS. 【Result】Three components of anti-gram-negative bacteria, B, C1 and C2, were purified from Paenibacillus polymyxa CP7 broth. Their molecular weight was 1 155 D, 1 169 D and 1 191 D, respectively. The molecular formula of C1 was C53H100O13N16, which was composed by six DAB, two threonine and two leucine, with the same structure as polymyxin E1. 【Conclusion】Three kinds of small molecule peptide of anti-gram-negative bacteria were isolated from the CP7 fermentation broth. It is speculated that B was also a member of the polymyxin family, and C2 may be a new family member.

Key words: strain CP7, Paenibacillus polymyxa , polymyxin, isolation and purification, structure analysis