Rational selection and antibacterial properties analysis of antimicrobial peptides producing bacteria CAO Ding1，MING Fei-ping1，XIA Feng-geng1，ZHANG Gao-xian1， HUANG Le-tian1，ZHANG Ling-hua2

One strain named GL08 which could produce antimicrobial peptides was breeded. By the combination of ultraviolet mutagenesis and using secondary metabolites- antimicrobial peptides as filter factors，a mutated strain was screened whose titer was higer than the starting strain by 30%. The fermentation study on the high-yield strain found that its antimicrobial peptides possessed stable titer，wide antimicrobial spectrum for their good bactericidal activity to a variety of gram-positive and negative bacteria. The fermented product from the strain GL08 was made into powder that was treated with different temperatures，pH，proteases and organic solvent，it was found that the antimicrobial peptides had certain tolerance for different threatments，and a long-term storage at room temperature. By strain breeding and analysis of the characteristics of antibacterial peptides，the antibacterial peptides from GL08 was expected to develop into a new type of feed additive.