Extraction And Inhibitory Properties Of Microbial Antimicrobial Peptide

Antimicrobial peptide (AMP) is an antimicrobial polypeptide against or kill many pathogens, which is widely recognized as natural biopreservatives, and has the potential to replace antibiotic. In this study, extraction of the AMP by Brevibacillus laterosporus S62-9 and its inhibitory properties were researched.For microbial AMP extraction, the first work should remove the producer strains from fermentation broth, the result showed that autoclaving at 121℃could remove it fast and thoroughly. A novel method to extract AMP by activated carbon adsorption was developed, and the results showed that inbihitory activity recovery 90%, and purification 15 times of the method. Then AMP extraction was concentrated by rotary evaporation, and product was obtained by vacuum freeze drying.In this work, the antibacterial properties of the AMP were carried out. The inhibitory results showed that Brevibacillus laterosporus S62-9 AMP is active on wide range of indicator strains, such as Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, Micrococcus luteus, Lactococcus lactis, Salmonellas, Escherichia coli and Pseudomonas aeruginosa. The AMP has good thermal stability, it was treated at 121℃for 15 min, lost its activity 30%, and at 100℃for 30 min, lost its activity 20%. It has strong pH stability, when it was treated pH3-11 at 30℃for 2h, only lost its activity 20% at pH6. It was a little sensitive toα-amylase and pepsin but insensitive to protease E, trypsin, lysozyme and lipase. It was also sensitive to SDS and TCA, insensitive to carbinol, alcohol, acetone, isopropanol, Tween-20, Tween-80, glacial acetic acid, mercaptoethanol and EDTA.Develop a feed additive AMP, The result showed that the additive also had antibacterial activity against indicator strains. After vacuum packaging, these complex can storage 6-weeks at 4℃, and its antimicrobial activity has no lost.