Application of high-speed centrifugation and high-performance liquid chro- matography to separation and purification obtained a new type of natural antibacteri- al substance from Escherichia co/i cell. Against Staphy/ococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus, Pseudomonas, solanacearum the minimal inhibitory concentration (MIC) was 2.5, 5, 0.625 iJg/ml, 0.625 and 1.25 g/ml, the minimum bactericidal concentration (MBC) was 5, 5, 1.25, 2.5, 2.5 g/ml, respectively. Composition identification of chemical method and m...