title: Biosurfactins production by Bacillus amyloliquefaciens R3 and their antibacterial activity against multi-drug resistant pathogenic E. coli.
abstract: In this work, the anti-Escherichia coli activity of the bioactive substances produced by Bacillus amyloliquefaciens R3 was examined. A new and cheap medium for production of the anti-E. coli substances which contained 20.0 g L(-1) soybean powder, 20.0 g L(-1) wheat flour, pH 6.0 was developed. A crude surfactant concentration of 0.48 mg mL(-1) was obtained after 27 h of 10-L fermentation, and the diameter of the clear zone on the plate seeded with the pathogenic E. coli 2# was 23.3 mm. A preliminary characterization suggested that the anti-E. coli substances produced by B. amyloliquefaciens R3 were the biosurfactins (F1, F2, F3, F4, and F5) with amino acids (GLLVDLL) and hydroxy fatty acids (of 12-15 carbons in length). It was found that all the strains of the pathogenic E. coli showed resistance to several different antibiotics, suggesting that they were the multi-drug resistance and all the strains of the pathogenic E. coli were sensitive to the biosurfactins, indicating that the biosurfactins produced by B. amyloliquefaciens R3 had a broad spectrum of antibacterial activity against the pathogenic E. coli with multi-drug resistant profiles. After the treatment with the purified biosurfactin (F1), the cell membrane of both the whole cells and protoplasts of the E. coli 2# was damaged and the whole cells of the bacterium were broken.
authors.affiliation: Unesco Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Chi
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Rong
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Mei-Juan
authors.initials: MJ
authors.lastname: Tang
authors.forename: Zhen-Ming
authors.initials: ZM
authors.lastname: Chi
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001407:Bacillus / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D024881:Drug Resistance, Bacterial; D018432:Drug Resistance, Multiple; D004926:Escherichia coli / Q000187:drug effects*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D055666:Lipopeptides / Q000737:chemistry; D013058:Mass Spectrometry; D008855:Microscopy, Electron, Scanning; D008856:Microscopy, Fluorescence; D010802:Phylogeny; D013025:Glycine max
chemical_list: D000900:Anti-Bacterial Agents; D055666:Lipopeptides