The purpose of this study was to optimize the fermentation conditions of antimicrobial peptides derived from Bacillus subtilis and explore its anti-inflammatory effect on chickens.The best nitrogen source,carbon source,initial pH value,temperature and inoculation amount for Bacillus subtilis K4 fermentation were screened out by single factor method.A strain of Bacillus subtilis K4,which can produce antimicrobial peptides,was fermented in a 50 L fermentor with the best fermentation medium and conditions,and the final fermentation broth was sprayed and dried with 20%water-soluble starch.Escherichia coli O2 was used as indicator bacteria for bacteriostatic test in vitro and anti-inflammatory test in chickens.The results showed that the best nitrogen source was peptone,the best carbon source was glucose,the initial pH value of culture medium was 7.0,the fermentation temperature was 37℃,and the inoculation amount was 5%.The number of viable bacteria in spray-dried bacteria powder was 4.60×1010 CFU/g.The bacteriostatic test in vitro showed that the bacteriostatic circle of spray-dried bacteria powder to O2 was 30 mm.The results of anti-inflammatory test showed that the survival rate of chickens infected with Escherichia coli was 65%,which was 18.18%higher than that of the drug control group,indicating that Bacillus subtilis K4 had the effect of inhibiting Escherichia coli and reducing the mortality after Escherichia coli infection.
Antibacterial peptideBacillus subtilis K4Bacteriostasis in vitroAnti-inflammatory
NETL
NSTL
万方数据
