Application of high-speed centrifugation and high-performance liquid chromatography to separation and purification obtained a new type of natural antibacterial substance from Escherichia coli cell. Against Staphylococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus, Pseudomonas, solanacearum the minimal inhibitory concentration(MIC) was 2.5 μg/ml, 5 μg/ml, 0.625 μg/ml,0.625 g/ml and 1.25 g/ml, the minimum bactericidal concentration(MBC) was 5 g/ml, 5 g/ml, 1.25 g/ml, 2.5 g/ml, 2.5 g/ml, respectively composition identifi...